Dr. Jacqueline Ferguson is a postdoctoral research fellow working with Dr. David Rehkopf at the Center for Population Health Sciences at Stanford and Dr. Donna Zulman through the Big Data-Scientist Training Enhancement Program (BD-STEP) at the Palo Alto VA.
She specializes in using secondary data sources such as occupational records, insurance claims, and electronic health records to study the relationship between environmental and social exposures and population health. Her research interests are widespread, but all center around methodology to handle time-varying exposures affected by prior exposure and methodology to account for multiple co-exposures or exposure mixtures.
Jacqueline’s doctoral research examined the impact of specific components of shift work on worker health, and identified night and rotational work as risk factors for hypertension and Type II diabetes. As a postdoc and BD-STEP fellow, Jacqueline is applying methodology, primarily developed for assessing chemical mixtures in environmental epidemiology, to examine co-occurring social determinants of health. Her research seeks to understand how multiple social determinants of health can simultaneously influence veteran care and health within the Veterans Health Administration.
Doctor of Philosophy, University of California Berkeley, Environmental Health (2019)
Master of Health Science, Johns Hopkins Bloomberg School of Public Health, Environmental Health Sciences (2013)
Bachelor of Arts, Johns Hopkins University, Public Health Studies (2012)
Virtual Care Expansion in the Veterans Health Administration During the COVID-19 Pandemic: Clinical Services and Patient Characteristics Associated with Utilization.
Journal of the American Medical Informatics Association : JAMIA
To describe the shift from in-person to virtual care within Veterans Affairs (VA) during the early phase of the COVID-19 pandemic, and to identify at-risk patient populations who require greater resources to overcome access barriers to virtual care.Outpatient encounters (N = 42,916,349) were categorized by care type (e.g. primary, mental health, etc.) and delivery method (e.g., in-person, video). For 5,400,878 Veterans, we used Generalized Linear models to identify patient sociodemographic and clinical characteristics associated with: 1) use of virtual (phone or video) care versus no virtual care and 2) use of video care versus no video care; between 3/11/2020 and 6/6/2020.By June, 58% of VA care was provided virtually compared to only 14% prior. Patients with lower income, higher disability, and more chronic conditions were more likely to receive virtual care during the pandemic. Yet, Veterans aged 45-64 and 65+ were less likely to use video care compared to those aged 18-44 (aRR 0.80 [95%CI 0.79, 0.82] and 0.50 [0.48, 0.52], respectively). Rural and homeless Veterans were 12% and 11% less likely to use video care compared to urban (0.88 [0.86, 0.90]) and non-homeless Veterans (0.89 [0.86, 0.92]).Veterans with high clinical or social need had higher likelihood of virtual service use early in the COVID-19 pandemic, however, older, homeless, and rural Veterans were less likely to have video visits, raising concerns for access barriers.While virtual care may expand access, access barriers must be addressed to avoid exacerbating disparities.
View details for DOI 10.1093/jamia/ocaa284
View details for PubMedID 33125032
Expanding Access through Virtual Care: The VA’s Early Experience with Covid-19
NEJM Catalyst Innovations in Care Delivery
View details for DOI 10.1056/CAT.20.0327
Night and rotational work exposure within the last 12 months and risk of incident hypertension
SCANDINAVIAN JOURNAL WORK ENVIRONMENT & HEALTH. 2019: 256–66
Objectives Shift work, such as alternating day and nights, causes chronobiologic disruptions which may cause an increase in hypertension risk. However, the relative contributions of the components of shift work ‒ such as shift type (eg, night work) and rotations (ie, switching of shift times; day to night) ‒ on this association are not clear. To address this question, we constructed novel definitions of night work and rotational work and assessed their associations with risk of incident hypertension. Methods A cohort of 2151 workers at eight aluminum manufacturing facilities previously studied for cardiovascular disease was followed from 2003 through 2013 for incident hypertension, as defined by ICD-9 insurance claims codes. Detailed time-registry data was used to classify each worker's history of rotational and night work. The associations between recent rotational work and night work in the last 12 months and incident hypertension were estimated using adjusted Cox proportional hazards models. Results Elevated hazard ratios (HR) were observed for all levels of recent night work (>0-5, >5-50, >50-95, >95-100%) compared with non-night workers, and among all levels of rotational work (<1, 1-10, >10-20, >20-30, and >30%) compared with those working <1% rotational work. In models for considering the combination of night and rotational work, workers with mostly night work and frequent rotations (≥50% night and ≥10% rotation) had the highest risk of hypertension compared to non-night workers [HR 4.00, 95% confidence interval (CI )1.69-9.52]. Conclusions Our results suggest recent night and rotational work may both be associated with higher rates of incident hypertension.
View details for DOI 10.5271/sjweh.3788
View details for Web of Science ID 000473172400006
View details for PubMedID 30614503
View details for PubMedCentralID PMC6494694
The Healthy Worker Survivor Effect: Target Parameters and Target Populations.
Current environmental health reports
2017; 4 (3): 364–72
We offer an in-depth discussion of the time-varying confounding and selection bias mechanisms that give rise to the healthy worker survivor effect (HWSE).In this update of an earlier review, we distinguish between the mechanisms collectively known as the HWSE and the statistical bias that can result. This discussion highlights the importance of identifying both the target parameter and the target population for any research question in occupational epidemiology. Target parameters can correspond to hypothetical workplace interventions; we explore whether these target parameters' true values reflect the etiologic effect of an exposure on an outcome or the potential impact of enforcing an exposure limit in a more realistic setting. If a cohort includes workers hired before the start of follow-up, HWSE mechanisms can limit the transportability of the estimates to other target populations. We summarize recent publications that applied g-methods to control for the HWSE, focusing on their target parameters, target populations, and hypothetical interventions.
View details for DOI 10.1007/s40572-017-0156-x
View details for PubMedID 28712046
View details for PubMedCentralID PMC5693751
Chronic obstructive pulmonary disease mortality: The Diesel Exhaust in Miners Study (DEMS).
BACKGROUND: Miners are highly exposed to diesel exhaust emissions from powered equipment. Although biologically plausible, there is little evidence based on quantitative exposure assessment, that long-term diesel exposure increases risk of chronic obstructive pulmonary disease (COPD). To fill this gap, we examined COPD mortality and diesel exhaust exposure in the Diesel Exhaust in Miners Study (DEMS).METHODS: We fit Cox models to estimate hazard ratios (HRs) for COPD mortality and cumulative exposure (mug/m3-years) to respirable elemental carbon (REC), a key metric for diesel exhaust exposure. Separate models were fit for ever-underground and surface-only miners to allow for effect modification. Exposure was lagged by 0, 10 and 15 years. In a secondary analysis, we addressed the healthy worker survivor effect by applying the parametric g-formula to handle time-varying confounding affected by prior exposure among ever-underground workers.RESULTS: Based on 140 cases, the HRs for COPD mortality increased as categories of lagged REC exposure increased for all workers. Among surface-only workers, those in the middle exposure category (0 lag) had a significantly elevated hazard ratio of 2.34 (95% CI: 1.11-4.61) relative to those in the lowest category. Among the ever-underground, that ratio was 1.35, with wide confidence intervals. Using the g-formula, we estimated that the lifetime cumulative risk of COPD mortality would have been reduced from the observed 5.0%-3.1% under a hypothetical intervention where all ever-underground workers were always unexposed.CONCLUSIONS: Our results suggest long term exposure to diesel exhaust may increase risk of COPD in miners, though power was limited.
View details for DOI 10.1016/j.envres.2019.108876
View details for PubMedID 31711661
Biomarkers of Secondhand Smoke Exposure in Waterpipe Tobacco Venue Employees in Istanbul, Moscow, and Cairo.
Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco
2018; 20 (4): 482–91
Most smoke-free legislation to reduce secondhand smoke (SHS) exposure exempts waterpipe (hookah) smoking venues. Few studies have examined SHS exposure in waterpipe venues and their employees.We surveyed 276 employees of 46 waterpipe tobacco venues in Istanbul, Moscow, and Cairo. We interviewed venue managers and employees and collected biological samples from employees to measure exhaled carbon monoxide (CO), hair nicotine, saliva cotinine, urine cotinine, urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and urine 1-hydroxypyrene glucuronide (1-OHPG). We estimated adjusted geometric mean ratios (GMR) of each SHS biomarker by employee characteristics and indoor air SHS measures.There were 73 nonsmoking employees and 203 current smokers of cigarettes or waterpipe. In nonsmokers, the median (interquartile) range concentrations of SHS biomarkers were 1.1 (0.2, 40.9) µg/g creatinine urine cotinine, 5.5 (2, 15) ng/mL saliva cotinine, 0.95 (0.36, 5.02) ng/mg hair nicotine, 1.48 (0.98, 3.97) pg/mg creatinine urine NNAL, 0.54 (0.25, 0.97) pmol/mg creatinine urine 1-OHPG, and 1.67 (1.33, 2.33) ppm exhaled CO. An 8-hour increase in work hours was associated with higher urine cotinine (GMR: 1.68, 95% CI: 1.20, 2.37) and hair nicotine (GMR: 1.22, 95% CI: 1.05, 1.43). Lighting waterpipes was associated with higher saliva cotinine (GMR: 2.83, 95% CI: 1.05, 7.62).Nonsmoking employees of waterpipe tobacco venues were exposed to high levels of SHS, including measurable levels of carcinogenic biomarkers (tobacco-specific nitrosamines and PAHs).Smoke-free regulation should be extended to waterpipe venues to protect nonsmoking employees and patrons from the adverse health effects of SHS.
View details for DOI 10.1093/ntr/ntx125
View details for PubMedID 28582531
View details for PubMedCentralID PMC6350617
An analysis of purchase price of legal and illicit cigarettes in urban retail environments in 14 low- and middle-income countries.
Addiction (Abingdon, England)
2017; 112 (10): 1854–60
To estimate and compare price differences between legal and illicit cigarettes in 14 low- and middle-income countries (LMIC).A cross-sectional census of all packs available on the market was purchased.Cigarette packs were purchased in formal retail settings in three major cities in each of 14 LMIC: Bangladesh, Brazil, China, Egypt, India, Indonesia, Mexico, Pakistan, the Philippines, Russia, Thailand, Turkey, Ukraine and Vietnam.A total of 3240 packs were purchased (range = 58 packs in Egypt to 505 in Russia). Packs were categorized as 'legal' or 'illicit' based on the presence of a health warning label from the country of purchase and existence of a tax stamp; 2468 legal and 772 illicit packs were in the analysis.Descriptive statistics stratified by country, city and neighborhood socio-economic status were used to explore the association between price and legal status of cigarettes.The number of illicit cigarettes in the sample setting was small (n < 5) in five countries (Brazil, Egypt, Indonesia, Mexico, Russia) and excluded from analysis. In the remaining nine countries, the median purchase price of legal cigarettes ranged from US$0.32 in Pakistan (n = 72) to US$3.24 in Turkey (n = 242); median purchase price of illicit cigarettes ranged from US$0.80 in Ukraine (n = 14) to US$3.08 in India (n = 41). The difference in median price between legal and illicit packs as a percentage of the price of legal packs ranged from 32% in Philippines to 455% in Bangladesh. Median purchase price of illicit cigarette packs was higher than that of legal cigarette packs in six countries (Bangladesh, India, Pakistan, Philippines, Thailand, Vietnam). Median purchase price of illicit packs was lower than that of legal packs in Turkey, Ukraine and China.The median purchase price of illicit cigarettes is higher than that of legal cigarette packs in Bangladesh, India, Pakistan, Philippines, Thailand, and Vietnam, Brazil, Egypt, Indonesia, Mexico, Russia appear to have few or no illicit cigarettes for purchase from formal, urban retailers.
View details for DOI 10.1111/add.13881
View details for PubMedID 28556313
View details for PubMedCentralID PMC5600117
Do cigarette health warning labels comply with requirements: A 14-country study.
2016; 93: 128–34
The Framework Convention on Tobacco Control, a global health treaty ratified by over 175 countries, calls on countries to ensure that tobacco packages carry health warning labels (HWLs) describing the harmful effects of tobacco use. We assessed the extent of compliance with 14 countries' HWL requirements. Unique cigarette packs were purchased in 2013 using a systematic protocol in 12 distinct neighborhoods within three of the ten most populous cities in the 14 low- and middle-income countries with the greatest number (count) of smokers. HWL compliance codebooks were developed for each country based on the details of country-specific HWL requirements, with up to four common compliance indicators assessed for each country (location, size, label elements, text size). Packs (n=1859) were double coded for compliance. Compliance was examined by country and pack characteristics, including parent company and brand family. Overall, 72% of coded cigarette packs were compliant with all relevant compliance indicators, ranging from 17% in the Philippines to 94% in Mexico. Compliance was highest for location of the warning (ranging from 75%-100%) and lowest for warning size (ranging from 46%-99%). Compliance was higher for packs bought in high SES neighborhoods, and varied by parent company and brand family. This multi-country study found at least one pack in every country - and many packs in some countries - that were not compliant with key requirements for health warning labels in the country of purchase. Non-compliance may be exacerbating health disparities. Tobacco companies should be held accountable for complying with country HWL requirements.
View details for DOI 10.1016/j.ypmed.2016.10.006
View details for PubMedID 27713100
Comparison of Culture-Based Methods for Identification of Colonization with Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus in the Context of Cocolonization.
Journal of clinical microbiology
2016; 54 (7): 1907–11
Two screening methods to detect staphylococcal colonization in humans were compared. Direct plating to CHROMagar (BD Diagnostics) was compared to a broth preenrichment followed by plating to Baird-Parker agar. The broth-enrichment method was comparable to CHROMagar for methicillin-resistant Staphylococcus aureas (MRSA) detection, but the enrichment method was optimum for recovery of coagulase-positive Staphylococcus spp.
View details for DOI 10.1128/JCM.00132-16
View details for PubMedID 27122377
View details for PubMedCentralID PMC4922128
A closer look at 'Cheap White' cigarettes.
2016; 25 (5): 527–31
Given the prominence of Cheap Whites in illicit tobacco discussions, we examined various definitions, market presence, brand proliferation, manufacturers, production locations, trademark ownership, prices and compliance with tax stamp and warning labels.Data from peer-reviewed and grey literature, newspapers, trademark registries, governments/international organisation reports, and the tobacco industry were contrasted with two visual legal requirements (tax stamps and warning labels) and prices from the Tobacco Pack Surveillance System (TPackSS).Multiple sources identified 82 Cheap White brands and 53 manufacturers operating at least 82 production facilities. One-third of these manufacturers are in the free zones of Russia, Cyprus and the UAE. Two-thirds of the 37 Cheap White brands in the TPackSS had neither the correct health warning nor the required tax stamp in at least one country where they were purchased. Cheap Whites are on average less expensive than all other brands, but the price gap is often not as large as anecdotally reported. The cheapest Cheap White cigarettes purchased in one of the TPackSS countries irrespective of the presence of legal signs were still more expensive than the least expensive other brands satisfying both legal requirements.We confirmed that many Cheap White brands do not comply with the legal requirements in countries where they are sold, but also found that some of these cigarettes appear to be sold legally even outside their country of origin. The presence of untaxed Cheap Whites undermines tobacco tax policies, while the availability of legal cheap cigarettes is a public health concern.
View details for DOI 10.1136/tobaccocontrol-2015-052540
View details for PubMedID 26418617
View details for PubMedCentralID PMC5036225
The Tobacco Pack Surveillance System: A Protocol for Assessing Health Warning Compliance, Design Features, and Appeals of Tobacco Packs Sold in Low- and Middle-Income Countries.
JMIR public health and surveillance
2015; 1 (2): e8
Tobacco remains the world's leading preventable cause of death, with the majority of tobacco-caused deaths occurring in low- and middle-income countries. The first global health treaty, the Framework Convention on Tobacco Control (FCTC), outlines a set of policy initiatives that have been demonstrated as effective in reducing tobacco use. Article 11 of the FCTC focuses on using the tobacco package to communicate tobacco-caused harms; it also seeks to restrict the delivery of misleading information about the product on the pack.The objective of this study was to establish a surveillance system for tobacco packs in the 14 low- and middle-income countries with the greatest number of smokers. The Tobacco Pack Surveillance System (TPackSS) monitors whether required health warnings on tobacco packages are being implemented as intended, and identifies pack designs and appeals that might violate or detract from the communication of harm-related information and undermine the impact of a country's tobacco packaging laws. The protocol outlined is intended to be applicable or adaptable for surveillance efforts in other countries.Tobacco packs were collected in 14 countries during 2013. The intention was, to the extent possible, to construct a census of "unique" pack presentations available for purchase in each country. The TPackSS team partnered with in-country field staff to implement a standardized protocol for acquiring packs from 36 diverse neighborhoods across three cities in each country. At the time of purchase, data on price and place of acquisition of each pack was recorded. The field staff, according to a standardized protocol, then photographed packs before they were shipped to the United States for coding and archiving.Each pack was coded for compliance with the country-specific health warning label laws, as well as for key design features of the pack and appeals of the branding elements. The coding protocols were developed based upon prior research, expert opinion, and communication theories. Each pack was coded by two independent coders, with consistency of personnel across the project. We routinely measured intercoder reliability, and only retained variables for which a good level of reliability was achieved. Variables where reliability was too low were not included in final analyses, and any inconsistencies in coding were resolved on a daily basis.Across the 14 countries, the TPackSS team collected 3307 tobacco packs. We have established a publicly accessible, Internet archive of these packs that is intended for use by the tobacco control policy advocacy and research community.
View details for DOI 10.2196/publichealth.4616
View details for PubMedID 27227142
View details for PubMedCentralID PMC4869212
Secondhand smoke in waterpipe tobacco venues in Istanbul, Moscow, and Cairo.
2015; 142: 568–74
The prevalence of waterpipe tobacco smoking has risen in recent decades. Controlled studies suggest that waterpipe secondhand smoke (SHS) contains similar or greater quantities of toxicants than cigarette SHS, which causes significant morbidity and mortality. Few studies have examined SHS from waterpipe tobacco in real-world settings. The purpose of this study was to quantify SHS exposure levels and describe the characteristics of waterpipe tobacco venues.In 2012-2014, we conducted cross-sectional surveys of 46 waterpipe tobacco venues (9 in Istanbul, 17 in Moscow, and 20 in Cairo). We administered venue questionnaires, conducted venue observations, and sampled indoor air particulate matter (PM2.5) (N=35), carbon monoxide (CO) (N=23), particle-bound polycyclic aromatic hydrocarbons (p-PAHs) (N=31), 4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (N=43), and air nicotine (N=46).Venue characteristics and SHS concentrations were highly variable within and between cities. Overall, we observed a mean (standard deviation (SD)) of 5 (5) waterpipe smokers and 5 (3) cigarette smokers per venue. The overall median (25th percentile, 75th percentile) of venue mean air concentrations was 136 (82, 213) µg/m(3) for PM2.5, 3.9 (1.7, 22) ppm for CO, 68 (33, 121) ng/m(3) for p-PAHs, 1.0 (0.5, 1.9) ng/m(3) for NNK, and 5.3 (0.7, 14) µg/m(3) for nicotine. PM2.5, CO, and p-PAHs concentrations were generally higher in venues with more waterpipe smokers and cigarette smokers, although associations were not statistically significant.High concentrations of SHS constituents known to cause health effects indicate that indoor air quality in waterpipe tobacco venues may adversely affect the health of employees and customers.
View details for DOI 10.1016/j.envres.2015.08.012
View details for PubMedID 26298558
View details for PubMedCentralID PMC4609287
Anatomical patterns of colonization of pets with staphylococcal species in homes of people with methicillin-resistant Staphylococcus aureus (MRSA) skin or soft tissue infection (SSTI).
2015; 176 (1-2): 202–8
Methicillin-resistant strains of Staphylococcus aureus (MRSA), Staphylococcus pseudintermedius (MRSP), and other pathogenic staphylococci can cause infections in companion animals and humans. Identification of colonized animals is fundamental to research and practice needs, but harmonized methods have not yet been established. To establish the optimal anatomic site for the recovery of methicillin-resistant coagulase positive staphylococci (CPS), survey data and swabs were collected from 196 pets (dogs, cats, reptiles, birds, fish and pocket pets) that lived in households with an MRSA-infected person. Using broth-enrichment culture and PCR for speciation, S. aureus was identified in 27 of 179 (15%) pets sampled at baseline and 19 of 125 (15%) pets sampled at a three-month follow-up home visit. S. pseudintermedius was isolated from 33 of 179 (18%) pets sampled at baseline and 21 of 125 (17%) of pets sampled at follow-up. The baseline MRSA and MRSP prevalence was 8% and 1% respectively from 145 mammalian pets. The follow-up MRSA and MRSP prevalence was 7% and <1% respectively from 95 mammalian pets. The mouth was the most sensitive single site sampled for isolation of S. aureus and S. pseudintermedius in mammals. In a subset of pets, from which all available isolates were identified, dual carriage of S. aureus and S. pseudintermedius was 22% at baseline and 11% at follow-up. These results identify the mouth as the most sensitive site to screen for pathogenic staphylococci and suggest that it should be included in sampling protocols.
View details for DOI 10.1016/j.vetmic.2015.01.003
View details for PubMedID 25623014