- Internal Medicine
Chief, Division of General Medical Disciplines, Stanford University (2009 - Present)
Professor of Medicine and Public Health, Yale University (1993 - 2009)
Director, Yale Occupational and Environmental Medicine Program (1980 - 2009)
Associate Professor of Medicine and Epidemiology, Yale University (1985 - 1993)
Assistant Professor of Medicine, Yale University (1980 - 1985)
Honors & Awards
Fifth Place Winner, Westinghouse National Science Talent Search (1967)
Faculty scholar in General Internal Medicine, Henry J. Kaiser Family Foundation (1988)
Member, Elected, Institute of Medicine (National Academy of Sciences) (1997)
Member, Elected, Connecticut Academy of Science & Engineering (2002)
Board Certification: Occupational Medicine, American Board of Preventive Medicine (1986)
Residency:Yale School of Medicine Appointments (1980) CT
Residency:Hospital of Saint Raphael (1984) CT
Board Certification: Internal Medicine, American Board of Internal Medicine (1979)
Medical Education:Yale School of Medicine Appointments (1976) CT
M.D., Yale University, M.D. (1976)
A.B., Harvard College, Philosophy and Physics (1971)
Current Research and Scholarly Interests
Social and environmental determinants of health; role of workplace physical environment and work organization as causes of chronic disease and disability
- Applied Grant-Writing Skills for Community and Clinical Research
MED 253 (Win)
- Independent Studies (5)
Prior Year Courses
Acoustic neuroma: potential risk factors and audiometric surveillance in the aluminium industry.
Occupational and environmental medicine
2014; 71 (9): 624-628
To look for an association between acoustic neuroma (AN) and participation in a hearing conservation programme (HCP) and also for an association between AN and possible occupational risk factors in the aluminium industry.We conducted a case-control analysis of a population of US aluminium production workers in 8 smelters and 43 other plants. Using insurance claims data, 97 cases of AN were identified between 1996 and 2009. Each was matched with four controls. Covariates included participation in a HCP, working in an aluminium smelter, working in an electrical job and hearing loss.In the bivariate analyses, covariates associated with AN were participation in the HCP (OR=1.72; 95% CI 1.09 to 2.69) and smelter work (OR=1.88; 95% CI 1.06 to 3.36). Electrical work was not significant (OR=1.60; 95% CI 0.65 to 3.94). Owing to high participation in the HCP in smelters, multivariate subanalyses were required. In the multivariate analyses, participation in the HCP was the only statistically significant risk factor for AN. In the multivariate analysis restricted to employees not working in a smelter, the OR was 1.81 (95% CI 1.04 to 3.17). Hearing loss, an indirect measure of in-ear noise dose, was not predictive of AN.Our results suggest the incidental detection of previously undiagnosed tumours in workers who participated in the company-sponsored HCP. The increased medical surveillance among this population of workers most likely introduced detection bias, leading to the identification of AN cases that would have otherwise remained undetected.
View details for DOI 10.1136/oemed-2014-102094
View details for PubMedID 25015928
Occupational injury risk by sex in a manufacturing cohort.
Occupational and environmental medicine
2014; 71 (9): 605-610
This study expands previous research comparing injury risk for women and men in a cohort of 24 000 US aluminium manufacturing workers in 15 facilities from 2001 to 2010.We compared injury rates (all injury, first aid, medical treatment, restricted work and lost work time) by sex and by job and sex. Using a mixed effect modelling approach, we calculated ORs and 95% CIs adjusting for age, job tenure, ethnicity and year as fixed effects and person, job and plant as random effects. Additionally, we modelled the data stratified by plant type to examine potential differences in injury risk between smelter (generally recognised as more hazardous) and fabrication production environments.Risk of injury was higher for women in four out of the five injury outcomes: all injuries combined (OR: 1.58, CI 1.48 to 1.67), injuries requiring first aid (OR: 1.61, CI 1.54 to 1.70), injuries requiring medical treatment (OR: 1.18, CI 1.03 to 1.36) and injuries requiring restricted work (OR: 1.65, CI 1.46 to 1.87). No difference in the risk of lost time injury by sex was found in this cohort. Analyses stratified by plant type showed similarly elevated injury risk for women, although the risk estimates were higher in smelters than fabrication plants.To our knowledge, this is the largest single-firm study examining injury risk by sex with sufficient data to appropriately adjust for job. We show a consistently higher injury risk for women compared with men in the smelting and fabrication environments.
View details for DOI 10.1136/oemed-2014-102083
View details for PubMedID 24924313
Individual-level and plant-level predictors of acute, traumatic occupational injuries in a manufacturing cohort
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2014; 71 (7): 477-483
Workplace and contextual factors that may affect risk for worker injury are not well described. This study used results from an employee job satisfaction survey to construct aggregate indicators of the work environment and estimate the relative contribution of those factors to injury rates in a manufacturing cohort.Principal components analysis was used to construct four plant-level factors from responses to a 32 question survey of the entire workforce, administered in 2006. Multilevel Poisson regression was used to evaluate the relationship between injury rate, individual-level and plant-level risk factors, unionisation and plant type.Plant-level 'work stress' (incident rate ratio (IRR)=0.50, 95% CI 0.28 to 0.90) was significant in the multilevel model, indicating the rate of injury for an average individual in that plant was halved (conditional on plant) when job stress decreased by a tertile. 'Overall satisfaction', 'work environment' and 'perception of supervisor' showed the same trend but were not significant. Unionisation was protective (IRR=0.40, 95% CI 0.17 to 0.95) as was any plant type compared with smelter.We demonstrated utility of data from a human resources survey to construct indicators of the work environment. Our research suggests that aspects of the work environment, particularly work stress and unionisation, may have a significant effect on risk for occupational injury, emphasising the need for further multilevel studies. Our work would suggest monitoring of employee perceptions of job stress and the possible inclusion of stress management as a component of risk reduction programmes.
View details for DOI 10.1136/oemed-2013-101827
View details for Web of Science ID 000337918300005
Disparities in early exposure to book sharing within immigrant families.
2014; 134 (1): e162-8
This study examined the early developmental context of children in immigrant families (CIF), measured by the frequency with which parents share books with their children.Trends in the frequency with which parents report book sharing, defined in this analysis as reading or sharing picture books with their young children, were analyzed across immigrant and nonimmigrant households by using data from the 2005, 2007, and 2009 California Health Interview Survey. Stepwise multivariate logistic regression assessed the likelihood that CIF shared books with parents daily.In this study, 57.5% of parents in immigrant families reported daily book sharing (DBS), compared with 75.8% of native-born parents. The lowest percentage of DBS was seen in Hispanic families with 2 foreign-born parents (47.1%). When controlling for independent variables, CIF with 2 foreign-born parents had the lowest odds of sharing books daily (odds ratio [OR]: 0.61; 95% confidence interval [CI]: 0.54-0.68). When stratified by race/ethnicity, separate multivariate logistic regressions revealed CIF status to be associated with lower odds of DBS for Asian (OR: 0.56; 95% CI: 0.38-0.81) and Hispanic CIF (OR: 0.49; 95% CI: 0.42-0.58).There is an association between the lower odds of DBS and parental immigrant status, especially for Hispanic and Asian children. This relationship holds after controlling for variables thought to explain differences in literacy-related practices, such as parental education and income. Because book sharing is central to children's development of early literacy and language skills, this disparity merits further exploration with the aim of informing future interventions.
View details for DOI 10.1542/peds.2013-3710
View details for PubMedID 24918215
- Semen quality, infertility and mortality in the USA HUMAN REPRODUCTION 2014; 29 (7): 1567-1574
0223 Marginal Structural Models in Occupational Epidemiology: An Application in the US Aluminium industry.
Occupational and environmental medicine
2014; 71: A30-?
To apply Marginal Structural Models (MSM) to address healthy workers survivor effect in a cohort study of active workers when time varying variables on health status and exposure are measured.We used Cox MSMs and inverse probability weighting to assess the effect of PM-2.5 exposure on incident ischaemic heart disease (IHD) in an active cohort of 11 966 US aluminium workers. The outcome was assessed using medical claims data from 1998 to 2012. Quantitative exposure metrics of current exposure to PM2.5 were dichotomized using different cutoffs and effects were assessed separately for smelters and fabrication. Risk score based on insurance claims was available as a time varying health status variable.Defining binary PM2.5 exposure by the 10th percentile cut-off, health status was affected by past exposure and predicted subsequent exposure in smelters, but not in fabrication. A Traditional cox model was appropriate for fabricators; the hazard ratio was 1.51(95% CI: 1.12 - 2.06) and was attenuated when considering higher exposure cutoffs. In smelters, Cox MSM Hazard Ratios for IHD comparing the effect of exposure in a population had everyone always been exposed to everyone always unexposed, using the 10(th) percentile exposure cutoff was 1.83 (95% CI: 1.14 - 2.94). Higher exposure cutoffs also resulted in attenuated effects.Marginal Structural Models can be used in active employment occupational cohorts to address time varying confounding. Results from the current study suggest that occupational exposure to PM2.5 in the aluminium industry increases the risk of IHD in both smelters and fabrication.
View details for DOI 10.1136/oemed-2014-102362.94
View details for PubMedID 25018317
0060 Particle size distribution in aluminium manufacturing facilities.
Occupational and environmental medicine
2014; 71: A6-?
As part of exposure assessment for an ongoing epidemiologic study of heart disease and fine particle exposures in aluminium manufacturing, area particle samples were collected in smelters and fabrication facilities to assess instrument reliability and particle size distribution at different process areas.Personal Modular Impactors (PMI) and Minimicro-orifice uniform deposition impactors (MiniMOUDI) were used to collect samples. The coefficient of variation (CV) of collocated samples of the same type was used to evaluate the reproducibility of the impactors. PM2.5 measured by PMI was compared to PM2.5 calculated from MiniMOUDI data to assess the validity of using PMI to measure fine particles in personal sampling. Mass median aerodynamic diameter (MMAD) was calculated to characterise particle size distribution at different locations.62 MiniMOUDI and 71 PMI samples were collected at 44 production areas. Most of CVs were less than 30%. The slope of the liner regression of PMI_PM2.5 versus MiniMOUDI_PM2.5 was 1.12 mg/m(3) per mg/m(3) (± 0.05), with correlation coefficient of 0.97 (± 0.01). MMADs in fabrications were significantly smaller and less variable than those in smelters (p = 0.001). The fraction of PM10 which was PM1.0 or PM0.56 was significantly higher in fabrications than in smelters (p < 0.001).The reproducibility for impactors was moderate to high. PM2.5 measured by PMI can be a valid measure for fine particle exposure in personal sampling. The concentrations of submicron and quasi-ultrafine particles were similar in fabrications and smelters. PM2.5 is not a good surrogate for ultrafine particles in this setting.
View details for DOI 10.1136/oemed-2014-102362.18
View details for PubMedID 25018415
0122 Approaches to developing exposure estimates that reflect temporal trends in total particulate matter in aluminium smelters.
Occupational and environmental medicine
2014; 71: A14-?
To evaluate different approaches for including time trends in quantitative exposures to total particulate matter (TPM) in an aluminium smelter for use in epidemiologic evaluation of incident heart disease, we compared the use of regression modelling to discrete modelling of changes in the workplace environment.We used an industrial hygiene database containing results for sampling conducted over 30 years and information on workplace environment (e.g. personal protective equipment policy, ventilation modifications, changes to materials or work organisation). The effects of these changes were tested with an analysis of variance model using log-transformed TPM concentrations. We compared the outcome of this approach to the use of a regression model for TPM concentrations over time.Time trends in 57 jobs in an aluminium smelter were evaluated by using 1123 TPM samples collected from 1984-2012. There was an overall decline in median TPM concentrations (mg/m(3)) at the smelter (3.7% per year). The trend was not observed in the majority individual jobs. The decreasing trend was concentrated in 14% of the jobs. The majority of jobs (61%) had no change over the time period, 19% had no consistent pattern of change, and 5% increased in TPM concentrations.Applying a global trend to worker exposures would result in misclassification error in epidemiologic evaluations. When possible, process changes should be used to define changes in worker exposures rather than using a facility- or industry-wide time trend. Future work will explore regression modelling as a way to explain any remaining time trends in TPM.
View details for DOI 10.1136/oemed-2014-102362.43
View details for PubMedID 25018259
0124 PM2.5 and Heart Disease in a Cohort of Aluminium Workers: An Application of Longitudinal Targeted Maximum Likelihood-based Estimation (TMLE).
Occupational and environmental medicine
2014; 71: A14-?
We estimated the effect of cumulative exposure to PM2.5 on the incidence of ischaemic heart disease (IHD) in aluminium workers followed for 15 years, adjusting for the healthy worker survivor effect. In previous analyses, higher cumulative exposure was found to be associated with lower mortality in this population.We used longitudinal TMLE to estimate the cumulative risk of ischaemic heart disease in the cohort if constantly exposed above an exposure cut-off and compared it to the risk if constantly exposed below. We stratified all analyses by work process because exposures were an order of magnitude higher in smelters than fabrication facilities.We selected cut-offs a priori at the median and 10th percentile exposure within each sub-cohort. Among the smelter workers, we estimated an increase in IHD risk of 2.1% (p = 0.22) after 15 years, comparing the always exposed to never exposed cohort using the median cut-off of 1.77 mg/m(3). The difference was 2.9% (p = 0.01) using the 10th percentile cutoff of 0.10 mg/m(3). For the fabrication workers, the differences were 0.1% (p = 0.47) using the median cut-off of 0.20 mg/m(3) and 2.5% (p < 0.01) for the 10th percentile cut-off of 0.06 mg/m(3). Results are presented as adjusted survival curves, describing the estimated cumulative risk for each cohort under each exposure regimen.The TMLE estimator allows us to observe an association between cumulative PM2.5 exposure and heart disease that was not visible using standard analytical techniques. This work represents the first application of longitudinal TMLE to the field of occupational epidemiology.
View details for DOI 10.1136/oemed-2014-102362.44
View details for PubMedID 25018260
- Population-Level Correlates of Preterm Delivery among Black and White Women in the US PLOS ONE 2014; 9 (4)
Contribution of health status and prevalent chronic disease to individual risk for workplace injury in the manufacturing environment
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2014; 71 (3): 159-166
An 'information gap' has been identified regarding the effects of chronic disease on occupational injury risk. We investigated the association of ischaemic heart disease, hypertension, diabetes, depression and asthma with acute occupational injury in a cohort of manufacturing workers from 1 January 1997 through 31 December 2007.We used administrative data on real-time injury, medical claims, workplace characteristics and demographics to examine this association. We employed a piecewise exponential model within an Andersen-Gill framework with a frailty term at the employee level to account for inclusion of multiple injuries for each employee, random effects at the employee level due to correlation among jobs held by an employee, and experience on the job as a covariate.One-third of employees had at least one of the diseases during the study period. After adjusting for potential confounders, presence of these diseases was associated with increased hazard of injury: heart disease (HR 1.23, 95% CI 1.11 to 1.36), diabetes (HR 1.17, 95% CI 1.08 to 1.27), depression (HR 1.25, 95% CI 1.12 to 1.38) and asthma (HR 1.14, 95% CI 1.02 to 1.287). Hypertension was not significantly associated with hazard of injury. Associations of chronic disease with injury risk were less evident for more serious reportable injuries; only depression and a summary health metric derived from claims remained significantly positive in this subset.Our results suggest that chronic heart disease, diabetes and depression confer an increased risk for acute occupational injury.
View details for DOI 10.1136/oemed-2013-101653
View details for Web of Science ID 000330849700003
- High prevalence of chronic kidney disease in a community survey of urban Bangladeshis: a cross-sectional study GLOBALIZATION AND HEALTH 2014; 10
Incident ischemic heart disease and recent occupational exposure to particulate matter in an aluminum cohort
JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY
2014; 24 (1): 82-88
Fine particulate matter (PM(2.5)) in air pollution, primarily from combustion sources, is recognized as an important risk factor for cardiovascular events but studies of workplace PM(2.5) exposure are rare. We conducted a prospective study of exposure to PM(2.5) and incidence of ischemic heart disease (IHD) in a cohort of 11,966 US aluminum workers. Incident IHD was identified from medical claims data from 1998 to 2008. Quantitative metrics were developed for recent exposure (within the last year) and cumulative exposure; however, we emphasize recent exposure in the absence of interpretable work histories before follow-up. IHD was modestly associated with recent PM(2.5) overall. In analysis restricted to recent exposures estimated with the highest confidence, the hazard ratio (HR) increased to 1.78 (95% CI: 1.02, 3.11) in the second quartile and remained elevated. When the analysis was stratified by work process, the HR rose monotonically to 1.5 in both smelter and fabrication facilities, though exposure was almost an order of magnitude higher in smelters. The differential exposure-response may be due to differences in exposure composition or healthy worker survivor effect. These results are consistent with the air pollution and cigarette smoke literature; recent exposure to PM(2.5) in the workplace appears to increase the risk of IHD incidence.
View details for DOI 10.1038/jes.2013.47
View details for Web of Science ID 000328604900012
Process of care compliance is associated with fewer diabetes complications.
American journal of managed care
2014; 20 (1): 41-52
To examine the association between processes measures of diabetes care and time to progression for 4 diabetes complications: coronary artery disease (CAD), stroke, heart failure (HF), and renal disease (RD).This retrospective study followed outcomes from 2003 through 2009 in a cohort of 1797 employees with diabetes who worked for a large US manufacturer and were enrolled in the same health insurance plan.Quality of care was measured by consensus standards for testing glycated hemoglobin, lipids, and microalbuminuria. Employees with diabetes who received all 3 measures of care in the baseline year (2003) were compared with those who received less complete testing. Cox proportional hazard regression models were used to assess potential associations between diabetes care and time to complications, controlling for potential confounders.Observed differences between the 2 groups in time to event were significant for 2 of the 4 complications: HF (hazard ratio [HR] = 0.39, 95% confidence interval [CI], 0.19-0.81; P = .0117) and RD (HR = 0.48, 95% CI, 0.24-0.95; P = .0339) and any of the 4 complications (HR = 0.66, 95% CI, 0.48-0.91; P = .0101). Differences in time to complication for CAD (HR = 0.70, 95% CI, 0.49-1.02; P = .0635) and stroke (HR = 0.63, 95% CI, 0.38-1.07; P = .0891) showed the same trend but were not significant.Employees with diabetes who received all 3 quality measures experienced fewer complications, risk-adjusting for other factors. These results provide support for the importance of care quality.
View details for PubMedID 24512164
Effect of systematic ergonomic hazard identification and control implementation on musculoskeletal disorder and injury risk
SCANDINAVIAN JOURNAL OF WORK ENVIRONMENT & HEALTH
2014; 40 (1): 57-65
This study aimed to examine the effect of an ergonomic hazard control (HC) initiative, undertaken as part of a company ergonomics standard, on worker injury risk.Using the company's ergonomic hazards database to identify jobs with and without ergonomic HC implementation and linking to individual job and injury histories, injury risk among person-jobs with HC implementation (the HC group) was compared to those without HC (NoHC group) using random coefficient models. Further analysis of the HC group was conducted to determine the effect of additional ergonomic hazards controlled on injury risk.Among 123 jobs at 17 plant locations, 347 ergonomic hazards were quantitatively identified during the study period. HC were implemented for 204 quantified ergonomic hazards in 84 jobs, impacting 10 385 persons (12 967 person-jobs). No HC were implemented for quantified ergonomic hazards in the remaining 39 jobs affecting 4155 persons (5046 person-jobs). Adjusting for age, sex, plant origin, and year to control for any temporal trend in injury risk, the relative risk (RR) for musculoskeletal disorder (MSD) was 0.85 and the RR for any injury or MSD was 0.92 in the HC compared to NoHC group. Among the HC group, each ergonomic hazard controlled was associated with risk reduction for MSD and acute injury outcomes (RR 0.93).Systematic ergonomic HC through participatory ergonomics, as part of a mandatory company ergonomics standard, is associated with MSD and injury risk reduction among workers in jobs with HC implemented.
View details for DOI 10.5271/sjweh.3394
View details for Web of Science ID 000333321400006
View details for PubMedID 24142048
Process of Care Compliance Is Associated With Fewer Diabetes Complications
AMERICAN JOURNAL OF MANAGED CARE
2014; 20 (1): 41-52
View details for Web of Science ID 000330599000004
Population-level correlates of preterm delivery among black and white women in the U.S.
2014; 9 (4)
This study examined the ability of social, demographic, environmental and health-related factors to explain geographic variability in preterm delivery among black and white women in the US and whether these factors explain black-white disparities in preterm delivery.We examined county-level prevalence of preterm delivery (20-31 or 32-36 weeks gestation) among singletons born 1998-2002. We conducted multivariable linear regression analysis to estimate the association of selected variables with preterm delivery separately for each preterm/race-ethnicity group.The prevalence of preterm delivery varied two- to three-fold across U.S. counties, and the distributions were strikingly distinct for blacks and whites. Among births to blacks, regression models explained 46% of the variability in county-level risk of delivery at 20-31 weeks and 55% for delivery at 32-36 weeks (based on R-squared values). Respective percentages for whites were 67% and 71%. Models included socio-environmental/demographic and health-related variables and explained similar amounts of variability overall.Much of the geographic variability in preterm delivery in the US can be explained by socioeconomic, demographic and health-related characteristics of the population, but less so for blacks than whites.
View details for DOI 10.1371/journal.pone.0094153
View details for PubMedID 24740117
High prevalence of chronic kidney disease in a community survey of urban Bangladeshis: a cross-sectional study.
Globalization and health
2014; 10: 9-?
The burden of chronic kidney disease (CKD) will rise in parallel with the growing prevalence of type two diabetes mellitus in South Asia but is understudied. Using a cross-sectional survey of adults living in a middle-income neighborhood of Dhaka, Bangladesh, we tested the hypothesis that the prevalence of CKD in this group would approach that of the U.S. and would be strongly associated with insulin resistance.We enrolled 402 eligible adults (>30 years old) after performing a multi-stage random selection procedure. We administered a questionnaire, and collected fasting serum samples and urine samples. We used the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to estimate glomerular filtration rate, and sex-specific cut offs for albuminuria: > 1.9 mg/mmol (17 mg/g) for men, and >2.8 mg/mmol (25 mg/g) for women. We assessed health-related quality of life using the Medical Outcomes Study Short Form-12 (SF-12).A total of 357 (89%) participants with serum samples comprised the analytic cohort. Mean age of was 49.5 (± 12.7) years. Chronic kidney disease was evident in 94 (26%). Of the participants with CKD, 58 (62%) had albuminuria only. A participant with insulin resistance had a 3.6-fold increase in odds of CKD (95% confidence interval 2.1 to 6.4). Participants with stage three or more advanced CKD reported a decrement in the Physical Health Composite score of the SF-12, compared with participants without CKD.We found an alarmingly high prevalence of CKD-particularly CKD associated with insulin resistance-in middle-income, urban Bangladeshis.
View details for DOI 10.1186/1744-8603-10-9
View details for PubMedID 24555767
Development of a job-exposure matrix for exposure to total and fine particulate matter in the aluminum industry
JOURNAL OF EXPOSURE SCIENCE AND ENVIRONMENTAL EPIDEMIOLOGY
2014; 24 (1): 89-99
Increasing evidence indicates that exposure to particulate matter (PM) at environmental concentrations increases the risk of cardiovascular disease, particularly PM with an aerodynamic diameter of less than 2.5 μm (PM(2.5)). Despite this, the health impacts of higher occupational exposures to PM(2.5) have rarely been evaluated. In part, this research gap derives from the absence of information on PM(2.5) exposures in the workplace. To address this gap, we have developed a job-exposure matrix (JEM) to estimate exposure to two size fractions of PM in the aluminum industry. Measurements of total PM (TPM) and PM(2.5) were used to develop exposure metrics for an epidemiologic study. TPM exposures for distinct exposure groups (DEGs) in the JEM were calculated using 8385 personal TPM samples collected at 11 facilities (1980-2011). For eight of these facilities, simultaneous PM(2.5) and TPM personal monitoring was conducted from 2010 to 2011 to determine the percent of TPM that is composed of PM(2.5) (%PM(2.5)) in each DEG. The mean TPM from the JEM was then multiplied by %PM(2.5) to calculate PM(2.5) exposure concentrations in each DEG. Exposures in the smelters were substantially higher than in fabrication units; mean TPM concentrations in smelters and fabrication facilities were 3.86 and 0.76 mg/m(3), and the corresponding mean PM(2.5) concentrations were 2.03 and 0.40 mg/m(3). Observed occupational exposures in this study generally exceeded environmental PM(2.5) concentrations by an order of magnitude.
View details for DOI 10.1038/jes.2013.53
View details for Web of Science ID 000328604900013
Systematic evaluation of environmental and behavioural factors associated with all-cause mortality in the United States National Health and Nutrition Examination Survey
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
2013; 42 (6): 1795-1810
Environmental and behavioural factors are thought to contribute to all-cause mortality. Here, we develop a method to systematically screen and validate the potential independent contributions to all-cause mortality of 249 environmental and behavioural factors in the National Health and Nutrition Examination Survey (NHANES).We used Cox proportional hazards regression to associate 249 factors with all-cause mortality while adjusting for sociodemographic factors on data in the 1999-2000 and 2001-02 surveys (median 5.5 follow-up years). We controlled for multiple comparisons with the false discovery rate (FDR) and validated significant findings in the 2003-04 survey (median 2.8 follow-up years). We selected 249 factors from a set of all possible factors based on their presence in both the 1999-2002 and 2003-04 surveys and linkage with at least 20 deceased participants. We evaluated the correlation pattern of validated factors and built a multivariable model to identify their independent contribution to mortality.We identified seven environmental and behavioural factors associated with all-cause mortality, including serum and urinary cadmium, serum lycopene levels, smoking (3-level factor) and physical activity. In a multivariable model, only physical activity, past smoking, smoking in participant's home and lycopene were independently associated with mortality. These three factors explained 2.1% of the variance of all-cause mortality after adjusting for demographic and socio-economic factors.Our association study suggests that, of the set of 249 factors in NHANES, physical activity, smoking, serum lycopene and serum/urinary cadmium are associated with all-cause mortality as identified in previous studies and after controlling for multiple hypotheses and validation in an independent survey. Whereas other NHANES factors may be associated with mortality, they may require larger cohorts with longer time of follow-up to detect. It is possible to use a systematic association study to prioritize risk factors for further investigation.
View details for DOI 10.1093/ije/dyt208
View details for Web of Science ID 000329870400041
View details for PubMedID 24345851
Urinary Triclosan is Associated with Elevated Body Mass Index in NHANES
2013; 8 (11)
Triclosan-a ubiquitous chemical in toothpastes, soaps, and household cleaning supplies-has the potential to alter both gut microbiota and endocrine function and thereby affect body weight.We investigated the relationship between triclosan and body mass index (BMI) using National Health and Nutrition Examination Surveys (NHANES) from 2003-2008. BMI and spot urinary triclosan levels were obtained from adults. Using two different exposure measures-either presence vs. absence or quartiles of triclosan-we assessed the association between triclosan and BMI. We also screened all NHANES serum and urine biomarkers to identify correlated factors that might confound observed associations.Compared with undetectable triclosan, a detectable level was associated with a 0.9-point increase in BMI (p<0.001). In analysis by quartile, compared to the lowest quartile, the 2nd, 3rd and 4th quartiles of urinary triclosan were associated with BMI increases of 1.5 (p<0.001), 1.0 (p = 0.002), and 0.3 (p = 0.33) respectively. The one strong correlate of triclosan identified in NHANES was its metabolite, 2,4-dichlorophenol (ρ = 0.4); its association with BMI, however, was weaker than that of triclosan. No other likely confounder was identified.Triclosan exposure is associated with increased BMI. Stronger effect at moderate than high levels suggests a complex mechanism of action.
View details for DOI 10.1371/journal.pone.0080057
View details for Web of Science ID 000327539800048
View details for PubMedID 24278238
- Associations between employee and manager gender: impacts on gender-specific risk of acute occupational injury in metal manufacturing BMC PUBLIC HEALTH 2013; 13
- High prevalence of type 2 diabetes among the urban middle class in Bangladesh BMC PUBLIC HEALTH 2013; 13
- Job insecurity during recessions: effects on survivors' work stress BMC PUBLIC HEALTH 2013; 13
- Preference for wine is associated with lower hip fracture incidence in post-menopausal women BMC WOMENS HEALTH 2013; 13
Health consequences of the 'Great Recession' on the employed: Evidence from an industrial cohort in aluminum manufacturing
SOCIAL SCIENCE & MEDICINE
2013; 92: 105-113
While the negative effects of unemployment have been well studied, the consequences of layoffs and downsizing for those who remain employed are less well understood. This study uses human resources and health claims data from a large multi-site fully insured aluminum company to explore the health consequences of downsizing on the remaining workforce. We exploit the variation in the timing and intensity of layoff to categorize 30 plants as high or low layoff plants. Next, we select a stably employed cohort of workers with history of health insurance going back to 2006 to 1) describe the selection process into layoff and 2) explore the association between the severity of plant level layoffs and the incidence of four chronic conditions in the remaining workforce. We examine four health outcomes: incident hypertension, diabetes, asthma/COPD and depression for a cohort of approximately 13,000 employees. Results suggest that there was an increased risk of developing hypertension for all workers and an increased risk of developing diabetes for salaried workers that remain at the plants with the highest level of layoffs. The hypertension results were robust to a several specification tests. In addition, the study design selected only healthy workers, therefore our estimates are likely to be a lower bound and suggest that adverse health consequences of the 2007-2009 recession may have affected a broader proportion of the population than previously expected.
View details for DOI 10.1016/j.socscimed.2013.04.027
View details for Web of Science ID 000322858200012
Piecewise exponential models to assess the influence of job-specific experience on the hazard of acute injury for hourly factory workers
BMC MEDICAL RESEARCH METHODOLOGY
An inverse relationship between experience and risk of injury has been observed in many occupations. Due to statistical challenges, however, it has been difficult to characterize the role of experience on the hazard of injury. In particular, because the time observed up to injury is equivalent to the amount of experience accumulated, the baseline hazard of injury becomes the main parameter of interest, excluding Cox proportional hazards models as applicable methods for consideration.Using a data set of 81,301 hourly production workers of a global aluminum company at 207 US facilities, we compared competing parametric models for the baseline hazard to assess whether experience affected the hazard of injury at hire and after later job changes. Specific models considered included the exponential, Weibull, and two (a hypothesis-driven and a data-driven) two-piece exponential models to formally test the null hypothesis that experience does not impact the hazard of injury.We highlighted the advantages of our comparative approach and the interpretability of our selected model: a two-piece exponential model that allowed the baseline hazard of injury to change with experience. Our findings suggested a 30% increase in the hazard in the first year after job initiation and/or change.Piecewise exponential models may be particularly useful in modeling risk of injury as a function of experience and have the additional benefit of interpretability over other similarly flexible models.
View details for DOI 10.1186/1471-2288-13-89
View details for Web of Science ID 000322382600001
View details for PubMedID 23841648
- (De)Personalized Medicine SCIENCE 2013; 339 (6124): 1155-1156
- Selection on Moral Hazard in Health Insurance AMERICAN ECONOMIC REVIEW 2013; 103 (1): 178-219
Impact of daily noise exposure monitoring on occupational noise exposures in manufacturing workers
INTERNATIONAL JOURNAL OF AUDIOLOGY
2013; 52: S3-S8
Despite the use of hearing protection devices (HPDs), noise induced hearing loss (NIHL) remains one of the most prevalent occupational conditions. A new technology allows for daily monitoring of noise exposures under HPDs. We report on an intervention employing the voluntary use of this technology in a worksite setting.Volunteers were fitted with a device allowing them to monitor noise exposure under their hearing protection on a daily basis. The trends in noise exposures for individuals who completed at least six months of the intervention were analysed.Recruitment occurred at three manufacturing facilities, with 127 workers enrolling and 66 workers actively using the device during their work shifts.Among volunteers downloading regularly, the percentage of daily exposures in excess of the OSHA action level (85 dBA) decreased from 14% to 8%, while the percentage of daily exposures in excess of 90 dBA decreased from 4% to less than 2%.Initial results from this longitudinal study indicate that volunteers find daily noise exposure monitoring to be feasible, and that workers who monitor daily are able to reduce exposures. The results of subject adherence shed light on the challenges and possibilities of worksite interventions for health and safety.
View details for DOI 10.3109/14992027.2012.743047
View details for Web of Science ID 000314532400002
View details for PubMedID 23373740
Further validation that claims data are a useful tool for epidemiologic research on hypertension
BMC PUBLIC HEALTH
The practice of using medical service claims in epidemiologic research on hypertension is becoming increasingly common, and several published studies have attempted to validate the diagnostic data contained therein. However, very few of those studies have had the benefit of using actual measured blood pressure as the gold standard. The goal of this study is to assess the validity of claims data in identifying hypertension cases and thereby clarify the benefits and limitations of using those data in studies of chronic disease etiology.Disease status was assigned to 19,150 employees at a U.S. manufacturing company where regular physical examinations are performed. We compared the presence of hypertension in the occupational medical charts against diagnoses obtained from administrative claims data.After adjusting for potential confounders, those with measured blood pressure indicating stage 1 hypertension were 3.69 times more likely to have a claim than normotensives (95% CI: 3.12, 4.38) and those indicating stage 2 hypertension were 7.70 times more likely to have a claim than normotensives (95% CI: 6.36, 9.35). Comparing measured blood pressure values identified in the medical charts to the algorithms for diagnosis of hypertension from the claims data yielded sensitivity values of 43-61% and specificity values of 86-94%.The medical service claims data were found to be highly specific, while sensitivity values varied by claims algorithm suggesting the possibility of under-ascertainment. Our analysis further demonstrates that such under-ascertainment is strongly skewed toward those cases that would be considered clinically borderline or mild.
View details for DOI 10.1186/1471-2458-13-51
View details for Web of Science ID 000314764800001
View details for PubMedID 23331960
Job insecurity during recessions: effects on survivors' work stress.
BMC public health
2013; 13: 929-?
Previous studies show a variety of negative health consequences for the remaining workforce after downsizing events. This study examined self-reported work stress from 2009-2012 in the context of a large multi-site aluminum manufacturing company that underwent severe downsizing in 2009.This study examined the association between work stress and working at a work site that underwent severe downsizing. We assessed the level of downsizing across thirty plants in 2009 and categorized seven as having undergone severe downsizing. We linked plant-level downsizing information to individual workers' responses to an annual work engagement survey, which included three work stress questions. From 2009 to 2012 over 14, 000 employees were asked about their experience of work stress. Though the surveys were anonymous, the surveys captured employees' demographic and employment characteristic as well as plant location. We used hierarchical logistic regressions to compare responses of workers at severely downsized plants to workers at all other plant while controlling for demographic and plant characteristics. Responses to the work stress questions and one control question were examined.In all yearly surveys salaried workers consistently reported having more work stress than hourly workers. There was no differential in work stress for workers at severely downsized plants in 2009. In 2010 to 2012, salaried workers who remained at severely downsized plants reported significantly higher work stress than salaried workers at all other plants across multiple work stress questions. Examination of the 2006 survey confirmed that there were no pre-existing differences in work stress among salaried employees working at plants that would eventually experience severe downsizing. In addition, there was no difference in responses to the control question at severely downsized plants.Salaried workers at plants with high layoffs experienced more work stress after 2009 than their counterparts at non-high layoff plants. Increased work stress is important to monitor and may be a mediating pathway through which the external economic environment leads to adverse health outcomes.
View details for DOI 10.1186/1471-2458-13-929
View details for PubMedID 24093476
Preference for wine is associated with lower hip fracture incidence in post-menopausal women.
BMC women's health
2013; 13: 36-?
Past studies of relationships between alcohol and hip fracture have generally focused on total alcohol consumed and not type of alcohol. Different types of alcohol consist of varying components which may affect risk of hip fracture differentially. This study seeks to examine the relationship between alcohol consumption, with a focus on type of alcohol consumed (e.g. beer, wine, or hard liquor) and hip fracture risk in post-menopausal women.The longitudinal cohort consisted of U.S. post-menopausal women aged 50-79 years enrolled between 1993-1998 in the Women's Health Initiative Clinical Trials and Observational Study (N=115,655).Women were categorized as non-drinkers, past drinkers, infrequent drinkers and drinkers by preference of alcohol type (i.e. those who preferred wine, beer, hard liquor, or who had no strong preference). Mean alcohol consumption among current drinkers was 3.3 servings per week; this was similar among those who preferred wine, beer and liquor. After adjustment for potential confounders, alcohol preference was strongly correlated with hip fracture risk (p = 0.0167); in particular, women who preferred wine were at lower risk than non-drinkers (OR=0.78; 95% CI 0.64-0.95), past drinkers (OR=0.85; 95% CI 0.72-1.00), infrequent drinkers (OR=0.73; 95% CI 0.61-0.88), hard liquor drinkers (OR=0.87; 95% CI 0.71-1.06), beer drinkers (OR=0.72; 95% CI 0.55-0.95) and those with no strong preference (OR=0.89; 95% CI 0.89; 95% CI 0.73-1.10).Preference of alcohol type was associated with hip fracture; women who preferentially consumed wine had a lower risk of hip fracture compared to non-drinkers, past drinkers, and those with other alcohol preferences.
View details for DOI 10.1186/1472-6874-13-36
View details for PubMedID 24053784
Associations between employee and manager gender: impacts on gender-specific risk of acute occupational injury in metal manufacturing.
BMC public health
2013; 13: 1053-?
Prior research has shown increased risk of injury for female employees compared to male employees after controlling for job and tasks, but have not explored whether this increased risk might be moderated by manager gender. The gender of one's manager could in theory affect injury rates among male and female employees through their managers' response to an employee's psychosocial stress or through how employees differentially report injuries. Other explanations for the gender disparity in injury experience, such as ergonomic factors or differential training, are unlikely to be impacted by supervisor gender. This study seeks to explore whether an employee's manager's gender modifies the effect of employee gender with regards to risk of acute injury.A cohort of employees and managers were identified using human resources and injury management data between January 1, 2002 and December 31, 2007 for six facilities of a large US aluminum manufacturing company. Cox proportional hazards models were employed to examine the interaction between employee gender and whether the employee had female only manager(s), male only manager(s), or both male and female managers on injury risk. Manager gender category was included as a time varying covariate and reassessed for each employee at the midpoint of each year.The percentage of departments with both female and male managers increased dramatically during the study period due to corporate efforts to increase female representation in management. After adjustment for fixed effects at the facility level and shared frailty by department, manager gender category does not appear to moderate the effect of employee gender (p = 0.717). Manager category was not a significant predictor (p = 0.093) of time to first acute injury. Similarly, having at least one female manager did not modify the hazard of injury for female employees compared to males (p = 0.899) and was not a significant predictor of time to first acute injury (p = 0.601).Prior findings suggest that female manufacturing employees are at higher risk for acute injury compared to males; this analysis suggests that this relationship is not affected by the gender of the employee's manager(s).
View details for DOI 10.1186/1471-2458-13-1053
View details for PubMedID 24207014
High prevalence of type 2 diabetes among the urban middle class in Bangladesh.
BMC public health
2013; 13: 1032-?
The prevalence of type-2 diabetes and metabolic syndrome are increasing in the developing world; we assessed their prevalence among the urban middle class in Bangladesh.In this cross-sectional survey (n = 402), we randomly selected consenting adults (≥ 30 years) from a middle-income neighborhood in Dhaka. We assessed demography, lifestyle, and health status, measured physical indices and blood pressure and obtained blood samples. We evaluated two primary outcomes: (1) type-2 diabetes (fasting blood glucose ≥ 7.0 mmol/L or hemoglobin A1C ≥ 6.5% (48 mmol/mol) or diabetes medication use) and (2) insulin resistance (type-2 diabetes or metabolic syndrome using International Diabetes Federation criteria).Mean age and Quételet's (body mass) index were 49.4 ± 12.6 years and 27.0 ± 5.1 kg/m²; 83% were married, 41% had ≥12 years of education, 47% were employed, 47% had a family history of diabetes. Thirty-five percent had type-2 diabetes and 45% had metabolic syndrome. In multivariate models older age and family history of diabetes were significantly associated with type-2 diabetes. Older age, female sex, overweight or obese, high wealth index and positive family history of diabetes were significantly associated with insulin resistance. Participants with type-2 diabetes or insulin resistance had significantly poorer physical health only if they had associated cardiovascular disease.The prevalence of type-2 diabetes and metabolic syndrome among the middle class in Dhaka is alarmingly high. Screening services should be implemented while researchers focus on strategies to lessen the incidence and morbidity associated with these conditions.
View details for DOI 10.1186/1471-2458-13-1032
View details for PubMedID 24172217
- How General Are Risk Preferences? Choices under Uncertainty in Different Domains AMERICAN ECONOMIC REVIEW 2012; 102 (6): 2606-2638
Cardiovascular diseases and Type 2 Diabetes in Bangladesh: A systematic review and meta-analysis of studies between 1995 and 2010
BMC PUBLIC HEALTH
Belief is that chronic disease prevalence is rising in Bangladesh since death from them has increased. We reviewed published cardiovascular (CVD) and Type 2 Diabetes Mellitus (T2DM) studies between 1995 and 2010 and conducted a meta-analysis of disease prevalence.A systematic search of CVD and T2DM studies yielded 29 eligible studies (outcome: CVD only = 12, T2DM only = 9, both = 8). Hypertension (HTN) was the primary outcome of CVD studies. HTN and T2DM were defined with objective measures and standard cut-off values. We assessed the study quality based on sampling frame, sample size, and disease evaluation. Random effects models calculated pooled disease prevalence (95% confidence interval) in studies with general population samples (n = 22).The pooled HTN and T2DM prevalence were 13.7% (12.1%-15.3%) and 6.7% (4.9%-8.6%), respectively. Both diseases exhibited a secular trend by 5-year intervals between 1995 and 2010 (HTN = 11.0%, 12.8%, 15.3%, T2DM = 3.8%, 5.3%, 9.0%). HTN was higher in females (M vs. F: 12.8% vs.16.1%) but T2DM was higher in males (M vs. F: 7.0% vs. 6.2%) (non-significant). Both HTN and T2DM were higher in urban areas (urban vs. rural: 22.2% vs. 14.3% and 10.2% vs. 5.1% respectively) (non-significant). HTN was higher among elderly and among working professionals. Both HTN and T2DM were higher in 'high- quality' studies.There is evidence of a rising secular trend of HTN and T2DM prevalence in Bangladesh. Future research should focus on the evolving root causes, incidence, and prognosis of HTN and T2DM.
View details for DOI 10.1186/1471-2458-12-434
View details for Web of Science ID 000311081700001
View details for PubMedID 22694854
Systematic evaluation of environmental factors: persistent pollutants and nutrients correlated with serum lipid levels
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
2012; 41 (3): 828-843
Both genetic and environmental factors contribute to triglyceride, low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) levels. Although genome-wide association studies are currently testing the genetic factors systematically, testing and reporting one or a few factors at a time can lead to fragmented literature for environmental chemical factors. We screened for correlation between environmental factors and lipid levels, utilizing four independent surveys with information on 188 environmental factors from the Centers of Disease Control, National Health and Nutrition Examination Survey, collected between 1999 and 2006.We used linear regression to correlate each environmental chemical factor to triglycerides, LDL-C and HDL-C adjusting for age, age(2), sex, ethnicity, socio-economic status and body mass index. Final estimates were adjusted for waist circumference, diabetes status, blood pressure and survey. Multiple comparisons were controlled for by estimating the false discovery rate and significant findings were tentatively validated in an independent survey.We identified and validated 29, 9 and 17 environmental factors correlated with triglycerides, LDL-C and HDL-C levels, respectively. Findings include hydrocarbons and nicotine associated with lower HDL-C and vitamin E (?-tocopherol) associated with unfavourable lipid levels. Higher triglycerides and lower HDL-C were correlated with higher levels of fat-soluble contaminants (e.g. polychlorinated biphenyls and dibenzofurans). Nutrients and vitamin markers (e.g. vitamins B, D and carotenes), were associated with favourable triglyceride and HDL-C levels.Our systematic association study has enabled us to postulate about broad environmental correlation to lipid levels. Although subject to confounding and reverse causality bias, these findings merit evaluation in additional cohorts.
View details for DOI 10.1093/ije/dys003
View details for Web of Science ID 000306417300030
View details for PubMedID 22421054
Geographic and Racial Variation in Premature Mortality in the US: Analyzing the Disparities
2012; 7 (4)
Life expectancy at birth, estimated from United States period life tables, has been shown to vary systematically and widely by region and race. We use the same tables to estimate the probability of survival from birth to age 70 (S(70)), a measure of mortality more sensitive to disparities and more reliably calculated for small populations, to describe the variation and identify its sources in greater detail to assess the patterns of this variation. Examination of the unadjusted probability of S(70) for each US county with a sufficient population of whites and blacks reveals large geographic differences for each race-sex group. For example, white males born in the ten percent healthiest counties have a 77 percent probability of survival to age 70, but only a 61 percent chance if born in the ten percent least healthy counties. Similar geographical disparities face white women and blacks of each sex. Moreover, within each county, large differences in S(70) prevail between blacks and whites, on average 17 percentage points for men and 12 percentage points for women. In linear regressions for each race-sex group, nearly all of the geographic variation is accounted for by a common set of 22 socio-economic and environmental variables, selected for previously suspected impact on mortality; R(2) ranges from 0.86 for white males to 0.72 for black females. Analysis of black-white survival chances within each county reveals that the same variables account for most of the race gap in S(70) as well. When actual white male values for each explanatory variable are substituted for black in the black male prediction equation to assess the role explanatory variables play in the black-white survival difference, residual black-white differences at the county level shrink markedly to a mean of -2.4% (+/-2.4); for women the mean difference is -3.7% (+/-2.3).
View details for DOI 10.1371/journal.pone.0032930
View details for Web of Science ID 000305347400001
View details for PubMedID 22529892
Hearing effects from intermittent and continuous noise exposure in a study of Korean factory workers and firefighters
BMC PUBLIC HEALTH
South Korea and surrounding countries in East Asia are believed to have the highest proportion in the world of high frequency hearing loss due to occupational noise exposure, yet there has been limited information published in international journals, and limited information for control of noise in local workplaces beyond strategies from western countries. We exploit medical surveillance information from two worker groups to enhance local knowledge about noise-induced hearing loss and explore the possible importance of shift work to risk.Four-years of hearing data were evaluated for 81 male farm machine factory workers and 371 male firefighters who had successfully completed a health examination and questionnaires for the duration of the study period. The averages of hearing thresholds at 2, 3, and 4 kHz were used as the primary end-point for comparison. Repeat measure analysis adjusted for age, exposure duration and smoking status was used to measure the difference in hearing threshold between the two groups.Noise levels were measured in the factory at a mean of 82 dBA, with a range of 66-97. No concurrent measurements were taken for the firefighters, but historic comparison values showed a wider range but a similar mean of 76-79 dBA. Although losses during follow-up were negligible, the factory workers had significantly (P < 0.0001) more hearing loss at the baseline of the study than the firefighters in both ears at 2, 3, and 4 kHz, adjusted for age, duration of employment and smoking status. Among those with 10 years of employment, mean losses at these frequencies among the factory workers fell into the impairment range (> 25 dB loss). Firefighters also showed increased losses associated with longer exposure duration, but these were significantly less marked. Losses at lower frequencies (< or = 1 kHz) were negligible in both groups.Korean work environments with continuous noise exposure in the measured range should consider implementation of a hearing conservation program. Further evaluation of hearing loss in workers exposed to irregular or intermittent high noise levels, such as firefighters, is also warranted.
View details for DOI 10.1186/1471-2458-12-87
View details for Web of Science ID 000300291500001
View details for PubMedID 22284753
Genetic variability in molecular responses to chemical exposure.
2012; 101: 437-457
Individuals differ in their response to environmental exposures. In the following, we describe examples and paradigms of studying heritable differences in response to exposure-commonly known as "gene-environment interaction" or "ecogenetics"-and their relation to disease etiology and susceptibility. Our discussion is framed in three parts. In the first, we describe replicated examples of studies that have typified the field, single genetic variant, and exposure associations to disease. Second, we describe how studies have scaled up search for interaction using genome-wide measurement modalities, bioinformatics, and model organisms. Finally, we discuss a more comprehensive representation of chemical exposures as the "envirome" and how we may use the envirome to examine interplay between genetics and the environment.
View details for DOI 10.1007/978-3-7643-8340-4_15
View details for PubMedID 22945578
Effect of daily noise exposure monitoring on annual rates of hearing loss in industrial workers
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2011; 68 (6): 414-418
Occupational noise-induced hearing loss (NIHL) is prevalent, yet evidence on the effectiveness of preventive interventions is lacking. The effectiveness of a new technology allowing workers to monitor daily at-ear noise exposure was analysed.Workers in the hearing conservation program of an aluminium smelter were recruited because of accelerated rates of hearing loss. The intervention consisted of daily monitoring of at-ear noise exposure and regular feedback on exposures from supervisors. The annual rate of change in high frequency hearing average at 2, 3 and 4 KHz before intervention (2000-2004) and 4 years after intervention (2006-2009) was determined. Annual rates of loss were compared between 78 intervention subjects and 234 controls in other company smelters matched for age, gender and high frequency hearing threshold level in 2005.Individuals monitoring daily noise exposure experienced on average no further worsening of high frequency hearing (average rate of hearing change at 2, 3 and 4 KHz = -0.5 dB/year). Matched controls also showed decelerating hearing loss, the difference in rates between the two groups being significant (p < 0.0001). Analysis of a subset of intervention subjects matched to controls for initial rate of hearing loss showed a similar trend but the difference was not statistically significant (p = 0.06).Monitoring daily occupational noise exposure inside hearing protection with ongoing administrative feedback apparently reduces the risk of occupational NIHL in industrial workers. Longer follow-up of these workers will help determine the significance of the intervention effect. Intervention studies for the prevention of NIHL need to include appropriate control groups.
View details for DOI 10.1136/oem.2010.055905
View details for Web of Science ID 000290516600007
View details for PubMedID 21193566
Aging, Transition, and Estimating the Global Burden of Disease
2011; 6 (5)
The World Health Organization's Global Burden of Disease (GBD) reports are an important tool for global health policy makers, however the accuracy of estimates for countries undergoing an epidemiologic transition is unclear. We attempted to validate the life table model used to generate estimates for all-cause mortality in developing countries.Data were obtained for males and females from the Human Mortality Database for all countries with available data every ten years from 1900 to 2000. These provided inputs for the GBD life table model and served as comparison observed data. Above age sixty model estimates of survival for both sexes differed substantially from those observed. Prior to the year 1960 for males and 1930 for females, estimated survival tended to be greater than observed; following 1960 for both males and females estimated survival tended to be less than observed. Viewing observed and estimated survival separately, observed survival past sixty increased over the years considered. For males, the increase was from a mean (sd) probability of 0.22 (0.06) to 0.46 (0.1). For females, the increase was from 0.26 (0.06) to 0.65 (0.08). By contrast, estimated survival past sixty decreased over the same period. Among males, estimated survival probability declined from 0.54 (0.2) to 0.09 (0.06). Among females, the decline was from 0.36 (0.12) to 0.15 (0.08).These results show that the GBD mortality model did not accurately estimate survival at older ages as developed countries transitioned in the twentieth century and may be similarly flawed in developing countries now undergoing transition. Estimates of the size of older-age populations and their attributable disease burden should be reconsidered.
View details for DOI 10.1371/journal.pone.0020264
View details for Web of Science ID 000291005800039
View details for PubMedID 21629652
Gender and sex differences in job status and hypertension
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2011; 68 (1): 16-23
Studies have shown greater health risks associated with blue-collar manufacturing employment for women than men. It remains challenging, however, to distinguish gendered job status (affected by family composition and other personal characteristics) from sex-linked biological differences influencing physiological response to workplace physical hazards.We examined the effects of hourly (blue-collar) status on incident hypertension among men and women, using health claims data for 14, 618 white- and blue-collar aluminium manufacturing employees in eight US states. To explore gender differences in job status, we developed sex-stratified propensity score models identifying key socioeconomic predictors of hourly status for men and women. To examine the effects of hourly employment on hypertension risk, after adjusting for gender differences in job status, we applied time-weighted logistic regression models, stratified by propensity score, with additional adjustment for socioeconomic confounders.Family structure (partnership, parity) influenced job status for both sexes; single mothers were more likely to hold hourly jobs (OR 2.02; 95% CI 1.37 to 2.97) and partnered men with children less likely (OR 0.68; 95% CI 0.56 to 0.83). Education, age at hire and race influenced job status for both sexes. The effect of hourly status on hypertension was significant only among women predicted to be hourly (OR 1.78; 95% CI 1.34 to 2.35).Our results indicate significant risks of hypertension associated with hourly status for women, possibly exacerbated by sociodemographic factors predicting hourly status (eg, single parenthood, low education). Greater attention to gender differences in job status, and finer exploration of sex-linked biological differences influencing responsivity to workplace exposures, is warranted.
View details for DOI 10.1136/oem.2009.049908
View details for Web of Science ID 000285182900005
View details for PubMedID 20864467
Prevalence of beryllium sensitization among aluminium smelter workers
2010; 60 (7): 569-571
Beryllium exposure occurs in aluminium smelters from natural contamination of bauxite, the principal source of aluminium.To characterize beryllium exposure in aluminium smelters and determine the prevalence rate of beryllium sensitization (BeS) among aluminium smelter workers.A population of 3185 workers from nine aluminium smelters owned by four different aluminium-producing companies were determined to have significant beryllium exposure. Of these, 1932 workers participated in medical surveillance programmes that included the serum beryllium lymphocyte proliferation test (BeLPT), confirmation of sensitization by at least two abnormal BeLPT test results and further evaluation for chronic beryllium disease in workers with BeS.Personal beryllium samples obtained from the nine aluminium smelters showed a range of <0.01-13.00 ?g/m(3) time-weighted average with an arithmetic mean of 0.25 ?g/m(3) and geometric mean of 0.06 ?g/m(3). Nine workers were diagnosed with BeS (prevalence rate of 0.47%, 95% confidence interval = 0.21-0.88%).BeS can occur in aluminium smelter workers through natural beryllium contamination of the bauxite and further concentration during the refining and smelting processes. Exposure levels to beryllium observed in aluminium smelters are similar to those seen in other industries that utilize beryllium. However, compared with beryllium-exposed workers in other industries, the rate of BeS among aluminium smelter workers appears lower. This lower observed rate may be related to a more soluble form of beryllium found in the aluminium smelting work environment as well as the consistent use of respiratory protection.
View details for DOI 10.1093/occmed/kqq097
View details for Web of Science ID 000282329000013
View details for PubMedID 20610489
ESTIMATING WELFARE IN INSURANCE MARKETS USING VARIATION IN PRICES
QUARTERLY JOURNAL OF ECONOMICS
2010; 125 (3): 877-921
We provide a graphical illustration of how standard consumer and producer theory can be used to quantify the welfare loss associated with inefficient pricing in insurance markets with selection. We then show how this welfare loss can be estimated empirically using identifying variation in the price of insurance. Such variation, together with quantity data, allows us to estimate the demand for insurance. The same variation, together with cost data, allows us to estimate how insurer's costs vary as market participants endogenously respond to price. The slope of this estimated cost curve provides a direct test for both the existence and nature of selection, and the combination of demand and cost curves can be used to estimate welfare. We illustrate our approach by applying it to data on employer-provided health insurance from one specific company. We detect adverse selection but estimate that the quantitative welfare implications associated with inefficient pricing in our particular application are small, in both absolute and relative terms.
View details for Web of Science ID 000281353500001
View details for PubMedID 21218182
Childhood Lead Exposure After the Phaseout of Leaded Gasoline: An Ecological Study of School-Age Children in Kampala, Uganda
ENVIRONMENTAL HEALTH PERSPECTIVES
2010; 118 (6): 884-889
Tetraethyl lead was phased out of gasoline in Uganda in 2005. Recent mitigation of an important source of lead exposure suggests examination and re-evaluation of the prevalence of childhood lead poisoning in this country. Ongoing concerns persist about exposure from the Kiteezi landfill in Kampala, the country's capital.We determined blood lead distributions among Kampala schoolchildren and identified risk factors for elevated blood lead levels (EBLLs; >or= 10 microg/dL). Analytical approach: Using a stratified, cross-sectional design, we obtained blood samples, questionnaire data, and soil and dust samples from the homes and schools of 163 4- to 8-year-old children representing communities with different risks of exposure.The mean blood lead level (BLL) was 7.15 microg/dL; 20.5% of the children were found to have EBLL. Multivariable analysis found participants whose families owned fewer household items, ate canned food, or used the community water supply as their primary water source to have higher BLLs and likelihood of EBLLs. Distance < 0.5 mi from the landfill was the factor most strongly associated with increments in BLL (5.51 microg/dL, p < 0.0001) and likelihood of EBLL (OR = 4.71, p = 0.0093). Dust/soil lead was not significantly predictive of BLL/EBLL.Lead poisoning remains highly prevalent among school-age children in Kampala. Confirmatory studies are needed, but further efforts are indicated to limit lead exposure from the landfill, whether through water contamination or through another mechanism. Although African nations are to be lauded for the removal of lead from gasoline, this study serves as a reminder that other sources of exposure to this potent neurotoxicant merit ongoing attention.
View details for DOI 10.1289/ehp.0901768
View details for Web of Science ID 000278591300036
View details for PubMedID 20194080
- Effects of Externally Rated Job Demand and Control on Depression Diagnosis Claims in an Industrial Cohort AMERICAN JOURNAL OF EPIDEMIOLOGY 2010; 171 (3): 303-311
Effects of externally rated job demand and control on depression diagnosis claims in an industrial cohort.
American journal of epidemiology
2010; 171 (3): 303-311
This study examined whether externally rated job demand and control were associated with depression diagnosis claims in a heavy industrial cohort. The retrospective cohort sample consisted of 7,566 hourly workers aged 18-64 years who were actively employed at 11 US plants between January 1, 1996, and December 31, 2003, and free of depression diagnosis claims during an initial 2-year run-in period. Logistic regression analysis was used to model the effect of tertiles of demand and control exposure on depression diagnosis claims. Demand had a significant positive association with depression diagnosis claims in bivariate models and models adjusted for demographic (age, gender, race, education, job grade, tenure) and lifestyle (smoking status, body mass index, cholesterol level) variables (high demand odds ratio = 1.39, 95% confidence interval: 1.04, 1.86). Control was associated with greater risk of depression diagnosis at moderate levels in unadjusted models only (odds ratio = 1.47, 95% confidence interval: 1.12, 1.93), while low control, contrary to expectation, was not associated with depression. The effects of the externally rated demand exposure were lost with adjustment for location. This may reflect differences in measurement or classification of exposure, differences in depression diagnosis by location, or other location-specific factors.
View details for DOI 10.1093/aje/kwp359
View details for PubMedID 20035011
Reproductive Outcomes Among Male and Female Workers at an Aluminum Smelter
JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2010; 52 (2): 137-143
Several adverse pregnancy outcomes were reported among female laboratory workers in a North American aluminum smelter. To determine whether these outcomes were associated with any occupational exposure at the plant, a cross-sectional survey was undertaken.Rates of miscarriage, premature singleton birth, and major congenital anomaly occurring during employment were compared with a reference group comprised of all pregnancies that occurred before employment.Among female workers, the excess of congenital anomalies among female laboratory workers that defined the initial cluster was observed, but no specific pattern was found.On the basis of these analyses, the increase in congenital anomalies could not be attributed to occupational exposures at the smelter nor could potential exposure likely explain the diverse anomalies described.
View details for DOI 10.1097/JOM.0b013e3181cb59bc
View details for Web of Science ID 000274491600004
View details for PubMedID 20134342
Long-term follow-up of beryllium sensitized workers from a single employer
BMC PUBLIC HEALTH
Up to 12% of beryllium-exposed American workers would test positive on beryllium lymphocyte proliferation test (BeLPT) screening, but the implications of sensitization remain uncertain.Seventy two current and former employees of a beryllium manufacturer, including 22 with pathologic changes of chronic beryllium disease (CBD), and 50 without, with a confirmed positive test were followed-up for 7.4 +/-3.1 years.Beyond predicted effects of aging, flow rates and lung volumes changed little from baseline, while DLCO dropped 17.4% of predicted on average. Despite this group decline, only 8 subjects (11.1%) demonstrated physiologic or radiologic abnormalities typical of CBD. Other than baseline status, no clinical or laboratory feature distinguished those who clinically manifested CBD at follow-up from those who did not.The clinical outlook remains favorable for beryllium-sensitized individuals over the first 5-12 years. However, declines in DLCO may presage further and more serious clinical manifestations in the future. These conclusions are tempered by the possibility of selection bias and other study limitations.
View details for DOI 10.1186/1471-2458-10-5
View details for Web of Science ID 000274831600003
View details for PubMedID 20047684
Work and its role in shaping the social gradient in health
BIOLOGY OF DISADVANTAGE: SOCIOECONOMIC STATUS AND HEALTH
2010; 1186: 102-124
Adults with better jobs enjoy better health: job title was, in fact, the social gradient metric first used to study the relationship between social class and chronic disease etiology, a core finding now replicated in most developed countries. What has been less well proved is whether this correlation is causal, and if so, through what mechanisms. During the past decade, much research has been directed at these issues. Best evidence in 2009 suggests that occupation does affect health. Most recent research on the relationship has been directed at disentangling the pathways through which lower-status work leads to adverse health outcomes. This review focuses on six areas of recent progress: (1) the role of status in a hierarchical occupational system; (2) the roles of psychosocial job stressors; (3) effects of workplace physical and chemical hazard exposures; (4) evidence that work organization matters as a contextual factor; (5) implications for the gradient of new forms of nonstandard or "precarious" employment such as contract and shift work; and (6) emerging evidence that women may be impacted differently by adverse working conditions, and possibly more strongly, than men.
View details for DOI 10.1111/j.1749-6632.2009.05338.x
View details for Web of Science ID 000277908000007
View details for PubMedID 20201870
- Heart disease & the workplace INDIAN JOURNAL OF MEDICAL RESEARCH 2009; 130 (4): 351-353
Invited Commentary: The Search for Preventable Causes of Cardiovascular Disease-Whither Work?
AMERICAN JOURNAL OF EPIDEMIOLOGY
2009; 169 (12): 1422-1425
The incidence and mortality of the major cardiovascular disorders vary sharply by occupation, but this is usually attributed to broad socioeconomic factors; the contributions of physical and psychosocial stressors at work remain obscure or controversial. Review of the ongoing studies of cardiovascular disease in the United States in this issue of the Journal demonstrates that few have either collected sufficient occupational data or used these data in published analyses to address this issue. There are compelling reasons to study this issue, starting with the sheer magnitude of the occupational gradient and disease prevalence. If only 5%-15% prove causally linked to preventable factors, an enormous disease-control opportunity would present itself. Moreover, the most suspect work factors-job stress, fine particulate dust, heat, noise, and shiftwork-are highly prevalent in the US workforce. Thankfully, there is evidence that many of the large ongoing studies are moving toward enhancing their occupational data and using what they have already collected. However, because of the complexity of studying these relations, the better solution is not retrofitting but designing studies in the future that combine de novo the conceptual frameworks and technical skills of occupational and social epidemiologists with those of more biologically focused investigators.
View details for DOI 10.1093/aje/kwp078
View details for Web of Science ID 000266953700002
View details for PubMedID 19429877
Healthcare for Obstructive Lung Disease in an Industrial Spirometry Surveillance Program
JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2009; 51 (3): 336-342
The efficacy of workplace spirometry surveillance programs is unclear. We examine whether aluminum industry workers with airflow obstruction (AO) received health care for obstructive lung disease.We performed a cross sectional analysis over 7 years of 6821 aluminum production workers. The primary outcome was the association between obstructive lung disease insurance claims and the presence of AO. We also examined whether the presence of claims was associated with increasing AO severity.Although workers with AO more frequently had claims, 60% of workers with AO, most frequently those with mild and borderline obstruction, had no claim.Workers with AO, particularly borderline and mild obstruction, frequently do not receive health care despite respiratory surveillance. Further investigation is needed to determine if workers with undiagnosed AO are symptomatic or have accelerated losses in lung function over time.
View details for DOI 10.1097/JOM.0b013e3181954ae6
View details for Web of Science ID 000264140300007
View details for PubMedID 19225419
Sex Differences in Injury Patterns Among Workers in Heavy Manufacturing
AMERICAN JOURNAL OF EPIDEMIOLOGY
2009; 169 (2): 161-166
The objective of the study was to determine if female workers in a heavy manufacturing environment have a higher risk of injury compared with males when performing the same job and to evaluate sex differences in type or severity of injury. By use of human resources and incident surveillance data for the hourly population at 6 US aluminum smelters, injuries that occurred from January 1, 1996, through December 21, 2005, were analyzed. Multivariate logistic regression, adjusted for job, tenure, and age category, was used to calculate odds ratios and 95% confidence intervals for female versus male injury risk for all injuries, recordable injuries, and lost work time injuries. The analysis was repeated for acute injuries and musculoskeletal disorder-related injuries separately. Female workers in this industry have a greater risk for sustaining all forms of injury after adjustment for age, tenure, and standardized job category (odds ratio = 1.365, 95% confidence interval: 1.290, 1.445). This excess risk for female workers persisted when injuries were dichotomized into acute injuries (odds ratio = 1.2) and musculoskeletal disorder-related injuries (odds ratio = 1.1). This study provides evidence of a sex disparity in occupational injury with female workers at higher risk compared with their male counterparts in a heavy manufacturing environment.
View details for DOI 10.1093/aje/kwn304
View details for Web of Science ID 000262518200006
View details for PubMedID 18996885
Workplace status and risk of hypertension among hourly and salaried aluminum manufacturing employees
SOCIAL SCIENCE & MEDICINE
2009; 68 (2): 304-313
An inverse relationship between workplace status and morbidity is well established; higher job status has been associated with reduced risks of heart disease, hypertension, and injury. Most research on job status, however, has focused on salaried populations, and it remains unclear whether job status operates similarly among hourly workers. Our objectives were to examine whether hourly status itself influences risk of hypertension after adjustment for socioeconomic confounders, and to explore the role of fine-scale job grade on hypertension incidence within hourly and salaried groups. We examined data for 14,999 aluminum manufacturing employees in 11 plants across the U.S., using logistic regression with adjustment for age, sex, race/ethnicity and other individual characteristics. Propensity score restriction was used to identify comparable groups of hourly and salaried employees, reducing confounding by sociodemographic characteristics. Job grade (coded 1 through 30, within hourly and salaried groups) was examined as a more refined measure of job status. Hourly status was associated with an increased risk of hypertension, after propensity restriction and adjustment for confounders. The observed effect of hourly status was stronger among women, although the propensity-restricted cohort was disproportionately male (96%). Among salaried workers, higher job grade was not consistently associated with decreased risk; among hourly employees, however, there was a significant trend, with higher job grades more protective against hypertension. Increasing the stringency of hypertension case criteria also increased the risk of severe or persistent hypertension for hourly employees.
View details for DOI 10.1016/j.socscimed.2008.10.014
View details for Web of Science ID 000263204900014
View details for PubMedID 19027215
- MARKETWATCH Who Chooses A Consumer-Directed Health Plan? HEALTH AFFAIRS 2008; 27 (6): 1671-1679
Who chooses a consumer-directed health plan?
2008; 27 (6): 1671-1679
Consumer-directed health plans (CDHPs) hold the promise of reining in health spending by giving consumers a greater stake in health care purchasing, yet little is known about employers' experience with these products. In examining the characteristics of those selecting a CDHP offered by one large employer, we found stronger evidence of selection than has been identified in prior research. Our findings suggest that in the context of plan choice, CDHPs may offer little opportunity to greatly lower employers' cost burden, and they highlight concerns about the potential for risk segmentation and the value of conferring preferential tax treatment to CDHPs.
View details for DOI 10.1377/hlthaff.27.6.1671
View details for PubMedID 18997225
The relationships between lost work time and duration of absence spells: Proposal for a payroll driven measure of absenteeism
JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2008; 50 (7): 840-851
To propose a standard measure of absenteeism (the work lost rate [WLR]) be included in future research to facilitate understanding and allow for translation of findings between scientific disciplines.Hourly payroll data derived from "punch clock" reports was used to compare various measures of absenteeism used in the literature and the application of the proposed metric (N = 4000 workers).Unpaid hours and full absent days were highly correlated with the WLR (r = 0.896 to 0.898). The highest percentage of unpaid hours (lost work time) is captured by absence spells of 1 and 2 days duration.The proposed WLR metric captures: 1) The range and distribution of the individual WLRs, 2) the percentage of subjects with no unpaid hours, and 3) the population WLR and should be included whenever payroll data is used to measure absenteeism.
View details for DOI 10.1097/JOM.0b013e31816b44dd
View details for Web of Science ID 000257723700015
View details for PubMedID 18617841
Organic solvent exposure and hearing loss in a cohort of aluminium workers
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2008; 65 (4): 230-235
Organic solvent exposure has been shown to cause hearing loss in animals and humans. Less is known about the risk of hearing loss due to solvent exposures typically found in US industry. The authors performed a retrospective cohort study to examine the relationship between solvent exposure and hearing loss in US aluminium industry workers.A cohort of 1319 workers aged 35 years or less at inception was followed for 5 years. Linkage of employment, industrial hygiene and audiometric surveillance records allowed for estimation of noise and solvent exposures and hearing loss rates over the study period. Study subjects were classified as "solvent exposed" or not, on the basis of industrial hygiene records linked with individual job histories. High frequency hearing loss was modelled as both a continuous and a dichotomous outcome.Typical solvent exposures involved mixtures of xylene, toluene and/or methyl ethyl ketone (MEK). Recorded solvent exposure levels varied widely both within and between jobs. In a multivariate logistic model, risk factors for high frequency hearing loss included age (OR = 1.06, p = 0.004), hunting or shooting (OR = 1.35, p = 0.049), noisy hobbies (OR = 1.74, p = 0.01), baseline hearing level (OR = 1.04, p<0.001) and solvent exposure (OR = 1.87, p = 0.004). A multivariate linear regression analysis similarly found significant associations between high frequency hearing loss and age (p<0.001), hunting or shooting (p<0.001), noisy hobbies (p = 0.03), solvent exposure (p<0.001) and baseline hearing (p = 0.03).These results suggest that occupational exposure to organic solvent mixtures is a risk factor for high frequency hearing loss, although the data do not allow conclusions about dose-response relationships. Industries with solvent-exposed workers should include such workers in hearing conservation programs.
View details for DOI 10.1136/oem.2006.031047
View details for Web of Science ID 000254121000005
View details for PubMedID 17567727
Beryllium sensitization in aluminum smelter workers
JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2008; 50 (2): 157-162
To determine whether beryllium-related disease exists among aluminum smelter workers.A total of 1278 employees from four aluminum smelters determined to have significant beryllium exposure based on 5 years of sampling were invited to participate in medical surveillance that included a respiratory symptoms questionnaire, spirometry, and blood beryllium lymphocyte proliferation test.Of these, 734 employees participated in the program. Beryllium exposure from 965 personal samples ranged from 0.002 to 13.00 microg/m time-weighted average, with a median of 0.05 microg/m, geometric mean of 0.05 microg/m, and arithmetic mean of 0.22 microg/m. Only two employees had confirmed beryllium sensitization (0.27%).There is evidence of beryllium sensitization among aluminum smelter workers. When compared with beryllium-exposed workers in other industries, aluminum smelter workers had lower rates of sensitization. The low beryllium sensitization rate observed may be related to work practices and the properties of the beryllium found in this work environment.
View details for DOI 10.1097/JOM.0b013e318161783f
View details for Web of Science ID 000253217100008
View details for PubMedID 18301172
Use of employer administrative Databases to identify systematic causes of injury in aluminum manufacturing
AMERICAN JOURNAL OF INDUSTRIAL MEDICINE
2007; 50 (9): 676-686
Employer administrative files are an underutilized source of data in epidemiologic studies of occupational injuries.Personnel files, occupational health surveillance data, industrial hygiene data, and a real-time incident and injury management system from a large multi-site aluminum manufacturer were linked deterministically. An ecological-level measure of physical job demand was also linked. This method successfully created a database containing over 100 variables for 9,101 hourly employees from eight geographically dispersed U.S. plants.Between 2002 and 2004, there were 3,563 traumatic injuries to 2,495 employees. The most common injuries were sprain/strains (32%), contusions (24%), and lacerations (14%). A multivariable logistic regression model revealed that physical job demand was the strongest predictor of injury risk, in a dose dependent fashion. Other strong predictors of injury included female gender, young age, short company tenure and short time on current job.Employer administrative files are a useful source of data, as they permit the exploration of risk factors and potential confounders that are not included in many population-based surveys. The ability to link employer administrative files with injury surveillance data is a valuable analysis strategy for comprehensively studying workplace injuries, identifying salient risk factors, and targeting workforce populations disproportionately affected.
View details for DOI 10.1002/ajim.20493
View details for Web of Science ID 000249250700005
View details for PubMedID 17676586
Extended work hours and risk of acute occupational injury: A case-crossover study of workers in manufacturing
AMERICAN JOURNAL OF INDUSTRIAL MEDICINE
2007; 50 (8): 597-603
This study was designed to determine whether injury risk among manufacturing workers was related to hours worked during the previous week.A case-crossover design was utilized to contrast hours worked prior to an injury shift with those worked prior to a non-injury shift for hourly workers. Paired t-tests were used to determine significance of the difference. Conditional logistic regression was used to assess dose-response.Hours worked prior to injury significantly exceeded hours during the control week. Workers who worked more than 64 hr in the week before the shift had an 88% excess risk compared to those who worked 40 hr or fewer, P < 0.05.The study provides evidence that injury risk is related to time worked during the previous week. Control of overtime in manufacturing may reduce risk of worker injury.
View details for DOI 10.1002/ajim.20486
View details for Web of Science ID 000248519300006
View details for PubMedID 17594716
Do ambient noise exposure levels predict hearing loss in a modern industrial cohort?
OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2007; 64 (1): 53-59
Much of what is known about the exposure-response relationship between occupational noise exposures and hearing loss comes from cross-sectional studies conducted before the widespread implementation of workplace hearing conservation programmes. Little is known about the current relationship of ambient noise exposure measurements to hearing loss risk.To examine the relationship between rates of high frequency hearing loss and measured levels of noise exposure in a modern industrial workforce.Ten-year hearing loss rates were determined for 6217 employees of an aluminium manufacturing company. Industrial hygiene and human resources records allowed for reconstruction of individual noise exposures. Hearing loss rates were compared to ANSI 3.44 predictions based on age and noise exposure. Associations between hearing loss, noise exposure, and covariate risk factors were assessed using multivariate regression.Workers in higher ambient noise jobs tended to experience less high frequency hearing loss than co-workers exposed at lower noise levels. This trend was also seen in stratified analyses of white males and non-hunters. At higher noise exposure levels, the magnitude of hearing loss was less than predicted by ANSI 3.44 formulae. There was no indication that a healthy worker effect could explain these findings. The majority of 10 dB standard threshold shifts (STS) occurred in workers whose calculated ambient noise exposures were less than or equal to 85 dBA.In this modern industrial cohort, hearing conservation efforts appear to be reducing hearing loss rates, especially at higher ambient noise levels. This could be related to differential use of hearing protection. The greatest burden of preventable occupational hearing loss was found in workers whose noise exposure averaged 85 dBA or less. To further reduce rates of occupational hearing loss, hearing conservation programmes may require innovative approaches targeting workers with noise exposures close to 85 dBA.
View details for DOI 10.1136/oem.2005.025924
View details for Web of Science ID 000243043100012
View details for PubMedID 16973736
Use of medical insurance claims data for occupational health research
JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2006; 48 (10): 1054-1061
The objective of this study was to demonstrate that health claims data, widely available due to the unique nature of the U.S. healthcare system, can be linked to other relevant databases such as personnel files and exposure data maintained by large employers. These data offer great potential for occupational health research.In this article, we describe the process for linking claims data to industrial hygiene exposure data and personnel files of a single large employer to conduct epidemiologic research.Our results demonstrate the ability to replicate previously published findings using commonly maintained data sets and illustrate methodological issues that may arise as newer hypotheses are tested in this way.Health claims files offer potential for epidemiologic research in the United States, although the full extent and guidelines for successful application await further clarification through empiric research.
View details for DOI 10.1097/01.jom.0000241049.23093.a4
View details for Web of Science ID 000241301100014
View details for PubMedID 17033505
Trends in the prevalence of hearing loss among young adults entering an industrial workforce 1985 to 2004
EAR AND HEARING
2006; 27 (4): 369-375
Studies have suggested that hearing loss due to recreational noise exposure may be on the rise among adolescents and young adults. This study examines whether the hearing status of young US adults entering an industrial workforce has worsened over the past 20 yr.The baseline audiograms of 2526 individuals ages 17 to 25 beginning employment at a multisite US corporation between 1985 and 2004 were analyzed to determine the yearly prevalence of hearing loss.Approximately 16% of the young adults in the sample had high frequency hearing loss (defined as hearing thresholds greater than 15 dB in either ear at 3,4, or 6 kHz). In a linear regression model, this prevalence decreased over the 20-yr period (odds ratio (OR) = 0.96, 95% confidence interval (CI): 0.94, 0.99). Almost 20% of subjects had audiometric "notches" consistent with noise exposure; this rate remained constant over the 20 yr, as did the prevalence (5%) of low frequency hearing loss.These results indicate that despite concern about widespread recreational noise exposures, the prevalence of hearing loss among a group of young US adults has not significantly increased over the past two decades.
View details for Web of Science ID 000238933500005
View details for PubMedID 16825886
Impact of OSHA final rule - Recording hearing loss: An analysis of an industrial audiometric dataset
JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE
2003; 45 (12): 1274-1280
The 2003 Occupational Safety and Health Administration (OSHA) Occupational Injury and Illness Recording and Reporting Final Rule changed the definition of recordable work-related hearing loss. We performed a study of the Alcoa Inc. audiometric database to evaluate the impact of this new rule. The 2003 rule increased the rate of potentially recordable hearing loss events from 0.2% to 1.6% per year. A total of 68.6% of potentially recordable cases had American Academy of Audiology/American Medical Association (AAO/AMA) hearing impairment at the time of recordability. On average, recordable loss occurred after onset of impairment, whereas the non-age-corrected 10-dB standard threshold shift (STS) usually preceded impairment. The OSHA Final Rule will significantly increase recordable cases of occupational hearing loss. The new case definition is usually accompanied by AAO/AMA hearing impairment. Other, more sensitive metrics should therefore be used for early detection and prevention of hearing loss.
View details for DOI 10.1097/01.jom.0000100040.45929.42
View details for Web of Science ID 000187227300008
View details for PubMedID 14665813