Clinical Focus

  • Pediatrics, General
  • Pediatrics

Academic Appointments

Administrative Appointments

  • Chief, Division of General Pediatrics, Department of Pediatrics (1985 - 1995)
  • Medical Director, Ambulatory Services, Lucile Packard Children's Hospital (1991 - 2012)

Honors & Awards

  • Kaiser Award for Excellence in Clinical Teaching, Stanford University School of Medicine (1986)

Professional Education

  • Residency: Stanford University School of Medicine (1979) CA
  • Fellowship: Childrens Hospital of Philadelphia Pediatric Pathology (1982) PA
  • Internship: Stanford University School of Medicine CA
  • Board Certification: American Board of Pediatrics, Pediatrics (1980)
  • Medical Education: Johns Hopkins University School of Medicine (1976) MD
  • M. D., Johns Hopkins University (1976)

Current Research and Scholarly Interests

Dr Hammer has had a longstanding interest in factors influencing the development of childhood obesity. In particular, his studies have focused on early determinants of eating behavior, physical activity, and parenting behavior in relation to early feeding decisions and parental influences on diet and eating. With the current epidemic of child obesity and it's comorbidities, he is currently involved in the development of obesity toolkits for pediatric providers at the state and local level and in the development and evaluation of protocols for use of bariatric surgery in the treatment of morbidly obese adolescents.

2023-24 Courses

All Publications

  • Improving Substance Use Prevention, Assessment, and Treatment Financing to Enhance Equity and Improve Outcomes Among Children, Adolescents, and Young Adults. Pediatrics Camenga, D. R., Hammer, L. D. 2022


    Access to timely prevention and treatment services remains challenging for many children, adolescents, young adults, and families affected by substance use. The American Academy of Pediatrics recognizes the scope and urgency of this problem and has developed this policy statement for consideration by Congress, federal and state policy makers, and public and private payers. This policy statement updates the 2001 policy statement "Improving Substance Abuse Prevention, Assessment, and Treatment Financing for Children and Adolescents" and provides recommendations for financing substance use prevention, assessment, and treatment of children, adolescents, and young adults.

    View details for DOI 10.1542/peds.2022-057992

    View details for PubMedID 35757960

  • The impact of reducing the frequency of night feeding on infant BMI. Pediatric research O'Shea, K. J., Ferguson, M. C., Esposito, L., Hammer, L. D., Avelis, C., Hertenstein, D., Gonzales, M. S., Bartsch, S. M., Wedlock, P. T., Siegmund, S. S., Lee, B. Y. 2021


    BACKGROUND: Teaching caregivers to respond to normal infant night awakenings in ways other than feeding is a common obesity prevention effort. Models can simulate caregiver feeding behavior while controlling for variables that are difficult to manipulate or measure in real life.METHODS: We developed a virtual infant model representing an infant with an embedded metabolism and his/her daily sleep, awakenings, and feeds from their caregiver each day as the infant aged from 6 to 12 months (recommended age to introduce solids). We then simulated different night feeding interventions and their impact on infant body mass index (BMI).RESULTS: Reducing the likelihood of feeding during normal night wakings from 79% to 50% to 10% lowered infant BMI from the 84th to the 75th to the 62nd percentile by 12 months, respectively, among caregivers who did not adaptively feed (e.g., adjust portion sizes of solid foods with infant growth). Among caregivers who adaptively feed, all scenarios resulted in relatively stable BMI percentiles, and progressively reducing feeding probability by 10% each month showed the least fluctuations.CONCLUSIONS: Reducing night feeding has the potential to impact infant BMI, (e.g., 10% lower probability can reduce BMI by 20 percentile points) especially among caregivers who do not adaptively feed.IMPACT: Teaching caregivers to respond to infant night waking with other soothing behaviors besides feeding has the potential to reduce infant BMI. When reducing the likelihood of feeding during night wakings from 79% to 50% to 10%, infants dropped from the 84th BMI percentile to the 75th to the 62nd by 12 months, respectively, among caregivers who do not adaptively feed. Night-feeding interventions have a greater impact when caregivers do not adaptively feed their infant based on their growth compared to caregivers who do adaptively feed. Night-feeding interventions should be one of the several tools in a multi-component intervention for childhood obesity prevention.

    View details for DOI 10.1038/s41390-021-01397-7

    View details for PubMedID 33664477

  • Can following formula-feeding recommendations still result in infants who are overweight or have obesity? Pediatric research Ferguson, M. C., O'Shea, K. J., Hammer, L. D., Hertenstein, D. L., Syed, R. M., Nyathi, S., Gonzales, M. S., Domino, M., Siegmund, S., Randall, S., Wedlock, P., Adam, A., Lee, B. Y. 2020


    BACKGROUND: Studies show that by 3 months, over half of US infants receive formula, and guidelines play a key role in formula feeding. The question then is, what might happen if caregivers follow guidelines and, more specifically, are there situations where following guidelines can result in infants who are overweight/have obesity?METHODS: We used our "Virtual Infant" agent-based model representing infant-caregiver pairs that allowed caregivers to feed infants each day according to guidelines put forth by Johns Hopkins Medicine (JHM), Children's Hospital of Philadelphia (CHOP), Children's Hospital of the King's Daughters (CHKD), and Women, Infants, and Children (WIC). The model simulated the resulting development of the infants from birth to 6 months. The two sets of guidelines vary in their recommendations, and do not provide studies that support amounts at given ages.RESULTS: Simulations identified several scenarios where caregivers followed JHM/CHOP/CHKD and WIC guidelines, but infants still became overweight/with obesity by 6 months. For JHM/CHOP/CHKD guidelines, this occurred even when caregivers adjusted feeding based on infant's weight. For WIC guidelines, when caregivers adjusted formula amounts, infants maintained healthy weight.CONCLUSIONS: WIC guidelines may be a good starting point for caregivers who adjust as their infant grows, but the minimum amounts for JHM/CHKD/CHOP recommendations may be too high.IMPACT: Our virtual infant simulation study answers the question: can caregivers follow current formula-feeding guidelines and still end up with an infant who is overweight or has obesity?Our study identified several situations in which unhealthy weight gain and/or weight loss could result from following established formula-feeding recommendations.Our study also suggests that the minimum recommended amount of daily formula feeding should be lower for JHM/CHOP/CHKD guidelines to give caregivers more flexibility in adjusting daily feeding levels in response to infant weight.WIC guidelines may be a good starting point for caregivers who adjust as their infant grows.In order to understand how to adjust guidelines, we can use computational simulation models, which serve as "virtual laboratories" to help overcome the logistical and ethical issues of clinical trials.

    View details for DOI 10.1038/s41390-020-0844-3

    View details for PubMedID 32179869

  • The Impact of Following Solid Food Feeding Guides on BMI Among Infants: A Simulation Study. American journal of preventive medicine Ferguson, M. C., O'Shea, K. J., Hammer, L. D., Hertenstein, D. L., Schwartz, N. J., Winch, L. E., Siegmund, S. S., Lee, B. Y. 2019


    INTRODUCTION: There are several recommendations advising caregivers when and how to introduce solid food to infants. These complementary feeding guides vary in terms of the recommendations for timing and portions. The objective of this study is to determine the impact of following different guidelines on weight trajectories of infants.METHODS: In 2018, the study team developed a computational simulation model to capture feeding behaviors, activity levels, metabolism, and body size of infants from 6 months to 1 year. Daily food intake of virtual infants based on feeding recommendations translated to changes in body weight. Next, simulations tested the impact of the following complementary feeding recommendations that provided amount, type, and timing of foods: Children's Hospital of Philadelphia, Johns Hopkins Medicine, Enfamil, and Similac.RESULTS: When virtual caregivers fed infants according to the four different guides, none of the simulated situations resulted in normal weight at 12 months when infants were also being breastfed along average observed patterns. Reducing breast milk portions in half while caregivers fed infants according to complementary feeding guidelines resulted in overweight BMIs between 9 and 11 months for Children's Hospital of Philadelphia, Johns Hopkins Medicine, and Enfamil guidelines. Cutting breast milk portions in half also led to infants reaching unhealthy underweight BMI percentiles between 7 and 11 months for female and male infants when caregivers followed Children's Hospital of Philadelphia, Johns Hopkins Medicine, and Similac guidelines.CONCLUSIONS: This study identified situations in which infants could reach unhealthy weights, even while following complementary feeding guidelines, suggesting that current recommended portion sizes should be tightened.

    View details for DOI 10.1016/j.amepre.2019.04.011

    View details for PubMedID 31353163

  • Targeted Reforms in Health Care Financing to Improve the Care of Adolescents and Young Adults PEDIATRICS Marcell, A. V., Breuner, C. C., Hammer, L., Hudak, M. L., Comm Adolescence, Comm Child Hlth Financing 2018; 142 (6)


    Significant changes have occurred in the commercial and government insurance marketplace after the passage of 2 federal legislation acts, the Patient Protection and Affordable Care Act of 2010 and the Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008. Despite the potential these 2 acts held to improve the health care of adolescents and young adults (AYAs), including the financing of care, there are barriers to achieving this goal. In the first quarter of 2016, 13.7% of individuals 18 to 24 years of age still lacked health insurance. Limitations in the scope of benefits coverage and inadequate provider payment can curtail access to health care for AYAs, particularly care related to sexual and reproductive health and mental and behavioral health. Some health plans impose financial barriers to access because they require families to absorb high cost-sharing expenses (eg, deductibles, copayments, and coinsurance). Finally, challenges of confidentiality inherent in the billing and insurance claim practices of some health insurance plans can discourage access to health care in the absence of other obstacles and interfere with provision of confidential care. This policy statement summarizes the current state of impediments that AYA, including those with special health care needs, face in accessing timely and appropriate health care and that providers face in serving these patients. These impediments include limited scope of benefits, high cost sharing, inadequate provider payment, and insufficient confidentiality protections. With this statement, we aim to improve both access to health care by AYAs and providers' delivery of developmentally appropriate health care for these patients through the presentation of an overview of the issues, specific recommendations for reform of health care financing for AYAs, and practical actions that pediatricians and other providers can take to advocate for appropriate payments for providing health care to AYAs.

    View details for DOI 10.1542/peds.2018-2998

    View details for Web of Science ID 000451372200049

    View details for PubMedID 30455343

  • A multidisciplinary approach to laparoscopic sleeve gastrectomy among multiethnic adolescents in the United States. Journal of pediatric surgery Jaramillo, J. D., Snyder, E. n., Farrales, S. n., Stevens, M. n., Wall, J. K., Chao, S. n., Morton, J. n., Pratt, J. S., Hammer, L. n., Shepard, W. E., Bruzoni, M. n. 2017


    Childhood obesity has become a serious public health problem in our country with a prevalence that is disproportionately higher among minority groups. Laparoscopic sleeve gastrectomy (LSG) is gaining attention as a safe bariatric alternative for severely obese adolescents.A retrospective study on morbidly obese adolescents that underwent LSG at our institution from 2009 to 2017. Primary outcomes were weight loss as measured by change in BMI and percent excess weight loss (%EWL) at 1 year after surgery, resolution of comorbidities and occurrence of complications.Thirty-eight patients, of whom 71% were female and 74% were ethnic minorities, underwent LSG between 2009 and 2016. Mean age was 16.8years, mean weight was 132.0kg and mean BMI was 46.7. There were no surgical complications. Mean %EWL was 19.4%, 27.9%, 37.4%, 44.9%, and 47.7% at 1.5, 3, 6, 9, and 12month follow up visits, respectively. Comorbidity resolution rates were 100% for hypertension and nonalcoholic fatty liver disease, 91% for diabetes, 44% for prediabetes, 82% for dyslipidemia and 89% for OSA.LSG is an effective and safe method of treatment of morbid obesity in adolescents as it can significantly decrease excess body weight and resolve comorbid conditions. Further studies are needed to investigate the long-term effects of LSG in adolescents.Descriptive case series with prospective database.IV.

    View details for PubMedID 28697852

  • Improving Healthy Eating in Families With a Toddler at Risk for Overweight: A Cluster Randomized Controlled Trial JOURNAL OF DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS Agras, W. S., Hammer, L. D., Huffman, L. C., Mascola, A., Bryson, S. W., Danaher, C. 2012; 33 (7): 529-534


    To ascertain whether a parent education program based on Satter's division of responsibility in feeding children (DOR) is effective in enhancing parent/child feeding interactions for children with an overweight/obese parent. The primary hypothesis was that the intervention would decrease parental pressure to eat.Sixty-two families with a child between 2 and 4 years with at least 1 overweight/obese parent were randomly allocated using a cluster design to either the DOR intervention or a control group. The control group focused on increasing family consumption of healthy foods and activity levels and enhancing child sleep duration. The primary outcome was parent pressure on their child to eat.The DOR intervention was superior to the control group in reducing the pressure to eat. Two moderators of pressure to eat were found: disinhibition of eating and hunger. The parents in the DOR group, irrespective of disinhibition levels, lowered the pressure to eat, whereas those in the control group with low disinhibition increased the pressure to eat. There were similar findings for hunger. Gender moderated restrictive feeding with DOR parents lowering restriction more than parents of the control group in girls only.The DOR intervention was more effective in reducing the parent pressure to eat and food restriction (in girls only) than the control group.

    View details for DOI 10.1097/DBP.0b013e3182618e1f

    View details for PubMedID 22947882

  • Puberty and gender interact to predict social anxiety symptoms in early adolescence JOURNAL OF ADOLESCENT HEALTH Deardorff, J., Hayward, C., Wilson, K. A., Bryson, S., Hammer, L. D., Agras, S. 2007; 41 (1): 102-104


    This study examines direct and interactive effects of puberty and gender on social anxiety symptoms in early adolescence. One hundred-six participants were assessed at ages 9.5 and 11 years. Results suggest that gender and puberty interact to predict social anxiety symptoms. Advanced puberty was associated with increased symptoms for girls only.

    View details for DOI 10.1016/j.jadohealth.2007.02.013

    View details for Web of Science ID 000247616200015

    View details for PubMedID 17577541

    View details for PubMedCentralID PMC2710300

  • Childhood risk factors for thin body preoccupation and social pressure to be thin JOURNAL OF THE AMERICAN ACADEMY OF CHILD AND ADOLESCENT PSYCHIATRY Agras, W. S., Bryson, S., Hammer, L. D., Kraemer, H. C. 2007; 46 (2): 171-178


    Thin body preoccupation and social pressure to be thin (TBPSP) in adolescence are risk factors for the development of full and partial bulimia nervosa and binge eating disorder. This study examined precursors of these potent risk factors.A prospective study followed 134 children from birth to 11.0 years and their parents. Recruitment began in January 1990 and ended in March 1991. The study was completed in December 2002.Two moderators identified different groups at risk for the development of TBPSP. A father with high body dissatisfaction characterized the largest group in which TBPSP was elevated for girls who were concerned about and attempted to modify their weight and for children with fathers who had a high drive for thinness. A child at risk for overweight characterized the second smaller group. Parental behaviors such as overcontrol of their child's eating, together with later pressure from parents and peers to be thin, were related to higher levels of TBPSP.Different pathways lead to the development of eating disorder psychopathology. These results suggest that prevention programs for eating disorders should begin in early childhood, possibly involving parental education and behavior change, and that different prevention programs may be required for different pathways.

    View details for DOI 10.1097/chi.0b01361802bd997

    View details for Web of Science ID 000243737900004

    View details for PubMedID 17242620

  • Methamphetamine use following bariatric surgery in an adolescent OBESITY SURGERY Dutta, S., Morton, J., Shepard, E., Peebles, R., Farrales-Nguyen, S., Hammer, L. D., Albanese, C. T. 2006; 16 (6): 780-782


    Bariatric surgery is increasingly popular as a therapeutic strategy for morbidly obese adolescents. Adolescence represents a sensitive period of psychosocial development, and children with considerable weight loss may experience greater peer acceptance, accompanied by both positive and negative influences. Substance abuse exists as one of these negative influences. We present the case of an adolescent bariatric surgical patient who abused methamphetamines in the postoperative period, with consequent nutritional instability. A concerted effort must be made in the preoperative assessment of adolescent bariatric patients to delineate a history of illicit drug use, including abuse of diet pills and stimulants. Excessive postoperative weight loss or micronutrient supplementation non-compliance should raise a suspicion of stimulant use and appropriate screening tests should be performed. The consequent appetite suppression may manifest with signs of malnutrition such as bradycardia, hypotension, and weakness. Inpatient nutritional rehabilitation and psychiatric assessment should be considered.

    View details for Web of Science ID 000238156200019

    View details for PubMedID 16756743

  • The relationship between parental factors at infancy and parent-reported control over children's eating at age 7 APPETITE Duke, R. E., Bryson, S., Hammer, L. D., Agras, W. S. 2004; 43 (3): 247-252


    The objective of this study was to determine predictors of parental control over children's eating. Data were obtained from 135 children and their parents from the Stanford Infant Growth Study. Assessments were obtained from parents at their child's birth and age 7. Parental body dissatisfaction at their child's birth predicted pressure to eat for both sons and daughters. In addition, minority status, parent being born outside of the United States, and a mother's early return to work predicted parental pressure to eat for sons. For daughters, an early maternal pushy feeding style also predicted parental pressure to eat. Parental hunger, a parental history of eating disorders and parent being born outside of the United States predicted food restriction for daughters. There were no predictors of food restriction for sons. We concluded that parental control appears not always to be simply a reaction to a child's lack of self-control or overweight, but may be present before such issues arise, particularly with the presence of certain cultural factors.

    View details for DOI 10.1016/j.appet.2004.05.006

    View details for Web of Science ID 000225236800003

    View details for PubMedID 15527926

  • Risk factors for childhood overweight: A prospective study from birth to 9.5 years JOURNAL OF PEDIATRICS Agras, W. S., Hammer, L. D., McNicholas, F., Kraemer, H. C. 2004; 145 (1): 20-25


    To ascertain risk factors for the development of overweight in children at 9.5 years of age.This was a prospective study of 150 children from birth to 9.5 years of age, with assessment of multiple hypothesized risk factors drawn from research reports.Five independent risk factors for childhood overweight were found. The strongest was parent overweight, which was mediated by child temperament. The remaining risk factors were low parent concerns about their child's thinness, persistent child tantrums over food, and less sleep time in childhood. Possible mechanisms by which each of these factors influence weight gain are outlined. Two different pathways to childhood overweight/obesity were found, depending on degree of parental overweight.There is evidence of considerable interaction between parent and child characteristics in the development of overweight. Several of the identified risk factors are amenable to intervention possibly leading to the development of early prevention programs.

    View details for DOI 10.1016/j.jpeds.2004.03.023

    View details for Web of Science ID 000222738500018

    View details for PubMedID 15238901

  • Bariatric surgery for severely overweight adolescents: Concerns and recommendations PEDIATRICS Inge, T. H., Krebs, N. F., Garcia, V. F., Skelton, J. A., Guice, K. S., Strauss, R. S., Albanese, C. T., Brandt, M. L., Hammer, L. D., Harmon, C. M., Kane, T. D., Klish, W. J., Oldham, K. T., Rudolph, C. D., Helmrath, M. A., Donovan, E., Daniels, S. R. 2004; 114 (1): 217-223


    As the prevalence of obesity and obesity-related disease among adolescents in the United States continues to increase, physicians are increasingly faced with the dilemma of determining the best treatment strategies for affected patients. This report offers an approach for the evaluation of adolescent patients' candidacy for bariatric surgery. In addition to anthropometric measurements and comorbidity assessments, a number of unique factors must be critically assessed among overweight youths. In an effort to reduce the risk of adverse medical and psychosocial outcomes and increase compliance and follow-up monitoring after bariatric surgery, principles of adolescent growth and development, the decisional capacity of the patient, family structure, and barriers to adherence must be considered. Consideration for bariatric surgery is generally warranted only when adolescents have experienced failure of 6 months of organized weight loss attempts and have met certain anthropometric, medical, and psychologic criteria. Adolescent candidates for bariatric surgery should be very severely obese (defined by the World Health Organization as a body mass index of > or =40), have attained a majority of skeletal maturity (generally > or =13 years of age for girls and > or =15 years of age for boys), and have comorbidities related to obesity that might be remedied with durable weight loss. Potential candidates for bariatric surgery should be referred to centers with multidisciplinary weight management teams that have expertise in meeting the unique needs of overweight adolescents. Surgery should be performed in institutions that are equipped to meet the tertiary care needs of severely obese patients and to collect long-term data on the clinical outcomes of these patients.

    View details for Web of Science ID 000222439200053

    View details for PubMedID 15231931

  • Behavioral validation, precursors, and concomitants of picky eating in childhood JOURNAL OF THE AMERICAN ACADEMY OF CHILD AND ADOLESCENT PSYCHIATRY Jacobi, C., Agras, W. S., Bryson, S., Hammer, L. D. 2003; 42 (1): 76-84


    To validate the concept of parent-reported picky eating using objective, laboratory-based measures and to identify both child and parental precursors and concomitants of picky eating.One hundred thirty-five infants were monitored from birth to 5.5 years. Behavioral measures of picky eating were obtained from standardized feedings at ages 3.5 and 5.5 years in the laboratory and at home. Child precursors were measures of infant sucking behavior; parental precursors were disinhibition of eating, restrained eating, body dissatisfaction, and body mass index. Parentally reported attitudes and behaviors thought to be related to pickiness and parental concomitants were taken from the Stanford Feeding Questionnaire. Child Temperament was assessed by the Children's Behavior Questionnaire.Picky eaters ate fewer foods and were especially more likely to avoid vegetables. Picky girls decreased their caloric intake between ages 3.5 and 5.5, whereas all other children increased their caloric intake. None of the included parental precursors was significantly related to pickiness. Picky eaters demonstrated a different sucking pattern with fewer sucks per feeding session at weeks 2 and 4. Finally, picky children displayed more parent-reported negative affect than nonpicky children.Parentally reported picky eating is associated with a consistent pattern of inhibited and selective eating beginning in infancy.

    View details for DOI 10.1097/01.CHI.0000024900.60748.2F

    View details for Web of Science ID 000180030000013

    View details for PubMedID 12500079

  • Early body mass index and other anthropometric relationships between parents and children INTERNATIONAL JOURNAL OF OBESITY Safer, D. L., Agras, W. S., Bryson, S., Hammer, L. D. 2001; 25 (10): 1532-1536


    To assess longitudinally the relationship between measures of adiposity in children over the first 8 y of life with that of their parents and to explore the role of parental adiposity in the development of childhood adiposity.Longitudinal study of measures of adiposity in children.A community sample from three health service systems including 114 children followed annually from infancy to age 8 and their 228 biological parents.Measurements were assessed at baseline for parents (6 months post-partum for mothers) and at regular intervals for children beginning at age 2 months. Measurements included weight, height, triceps skinfold, subscapular skinfold, midarm circumference, waist and hip.The major findings were: (1) significant correlations between parental body mass index (BMI), both maternal and paternal, and their biological offspring first emerged at age 7; (2) children with two overweight parents had consistently elevated BMI compared to children with either no overweight parents or one overweight parent. These differences became significant beginning at age 7.This study supports the hypothesis that familial factors (biological and/or environmental) affecting the development of adiposity emerge at specific ages and are related to the adiposity of both parents.

    View details for Web of Science ID 000171515800021

    View details for PubMedID 11673777

  • Prolonged bottle feeding in a cohort of children: Does it affect caloric intake and dietary composition? CLINICAL PEDIATRICS Safer, D. L., Bryson, S., Agras, W. S., Hammer, L. D. 2001; 40 (9): 481-487


    Little is known about the consequences to children of bottle feeding prolonged beyond age 1 year on caloric intake and overall dietary composition. To obtain these data, 165 children, followed up from infancy, were assessed in these respects for a 24-hour period at age 3 1/2 years. Bottle-fed children (n = 14) consumed more milk than their weaned counterparts (p < 0.001), had a higher mean daily calcium intake (p < 0.05), received fewer calories from carbohydrates (p = 0.034), and received a greater percentage of calories from protein (p = 0.033). There were no significant differences between the groups in total caloric intake, total iron intake, total volume ofjuice, or calories from fat. Pediatricians questioned about the effects of continuing to offer children nutritive liquids from bottles as well as cups (versus offering cups alone) may inform parents that this feeding practice is associated with significantly greater milk consumption and daily calcium intake. However, this study could not find evidence that prolonged bottle feeding at age 3 1/2 years is associated with a significantly decreased total daily iron intake or an increased risk for factors associated with adiposity such as a greater daily calorie intake, a higher body mass index, or greater percentage of total calories derived from fat.

    View details for Web of Science ID 000171030600002

    View details for PubMedID 11583046

  • Predicting children's reported eating disturbances at 8 years of age JOURNAL OF THE AMERICAN ACADEMY OF CHILD AND ADOLESCENT PSYCHIATRY Jacobi, C., Agras, W. S., Hammer, L. 2001; 40 (3): 364-372


    To examine differential parental influences on eating attitudes and behaviors of 8-year-old children with a specific focus on gender effects and to assess the specificity of this relationship.One hundred eight infants were monitored from birth and interviewed at age 8 for eating disturbances and negative affect with an adaptation of the McKnight Risk Factor Survey. Parental measures included the Three Factor Eating Questionnaire subscales Disinhibition and Restraint as well as body mass index, assessed at study entry.No gender differences were found for frequencies of children's self-reported eating disturbances. Higher maternal restraint scores predicted worries about being too fat in girls but not in boys. Higher maternal disinhibition scores also differentially predicted weight control behaviors in their daughters. Negative affect in the child was (weakly) predicted by higher maternal body mass index. No association between paternal predictors of disturbed eating and the child's eating disturbances and negative emotionality was found.The impact of maternal eating disorders and disturbances is much stronger than that of fathers and is specifically directed at their daughters. The clinical importance of these disturbances in terms of precursors of adolescent eating disorders has to be determined by monitoring the sample through puberty.

    View details for Web of Science ID 000167200000017

    View details for PubMedID 11288779

  • Risk factors for the emergence of childhood eating disturbances: A five-year prospective study INTERNATIONAL JOURNAL OF EATING DISORDERS Stice, E., Agras, W. S., Hammer, L. D. 1999; 25 (4): 375-387


    Research suggests that eating problems are often present by preadolescence, yet little is known about the age of emergence of these early eating disturbances or risk factors for these behaviors. Thus, we investigated the timing of onset of disturbed eating during childhood and the predictors of these behaviors.These aims were addressed by following a sample of children and their parents (N = 216) for the first 5 years of the children's lives.Data suggested that the risk for emergence of inhibited eating, secretive eating, overeating, and vomiting increased annually through age 5. Maternal body dissatisfaction, internalization of the thin-ideal, dieting, bulimic symptoms, and maternal and paternal body mass prospectively predicted the emergence of childhood eating disturbances. Infant feeding behavior and body mass during the first month of life also predicted the emergence of these behaviors.Results suggest that eating disturbances emerge during childhood and may be a function of certain parental and child characteristics.

    View details for Web of Science ID 000079497800002

    View details for PubMedID 10202648

  • Can mothers influence their child's eating behavior? JOURNAL OF DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS Drucker, R. R., Hammer, L. D., Agras, W. S., Bryson, S. 1999; 20 (2): 88-92


    This study examined the relationship between general maternal parenting style, maternal eating cues, and a child's eating behavior during mealtime. We expected that the general style would relate to the number of specific eating cues and that mothers who used more eating prompts would have children that ate more and at a faster rate. Seventy-seven children (39 girls, 38 boys), aged 3.5 years, visited the laboratory with their mothers for a videotaped lunch. Videotapes of each laboratory visit were coded for the child's eating rate and maternal parenting style, which was measured as the level of maternal control and support and the number and type of eating prompts given during a meal. Caloric intake was also calculated. The number and rate of verbal and physical encouragements and discouragements were significantly related to measures of general maternal parenting style and meal duration. The rates of food offers, food presentations, and total prompts were all significantly related to the child's rate of calorie intake. However, a mother's level of support or control was not related to the child's eating behavior. Although general maternal parenting style did not predict the child's eating behavior, these behaviors were related to the frequency of maternal eating prompts, which in turn were significantly related to the number of calories eaten and the time spent eating by the child. Children who ate the fastest had mothers who delivered eating prompts at a higher frequency. These findings may have implications for the development of obesity later in childhood, as a function of rapid eating or of poor self-regulation.

    View details for Web of Science ID 000079667500003

    View details for PubMedID 10219686

  • A prospective study of the influence of eating-disordered mothers on their children INTERNATIONAL JOURNAL OF EATING DISORDERS Agras, S., Hammer, L., McNicholas, F. 1999; 25 (3): 253-262


    This study examined the effects of eating disordered mothers on their children.Women with a past or present eating disorder (ED; N = 41) and non-eating disordered women (NED); N = 153) and their offspring were followed prospectively.Female infants of ED mothers sucked significantly faster and were weaned 9 months later than offspring of NED mothers. ED mothers fed their children on a less regular schedule, used food for nonnutritive purposes, and demonstrated significantly higher concern about their daughters' weight than NED mothers from 2 years of age onward. At 5 years, the offspring of ED mothers were reported to demonstrate greater negative affect than the offspring of NED mothers.The female offspring of ED mothers demonstrate a high avidity for feeding early in life which, combined with increased maternal concern over their daughters weight and the use of food for nonnutritive purposes, may pose a serious risk for the later development of an eating disorder.

    View details for Web of Science ID 000079349300002

    View details for PubMedID 10191989

  • Development of feeding practices during the first 5 years of life ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE Hammer, L. D., Bryson, S., Agras, W. S. 1999; 153 (2): 189-194


    To understand the transition from breast-and bottle-feeding to solid-feeding and factors that might affect the duration of breast- and bottle-feeding.Cohort followed up from birth with relatively well-educated, middle-class parents.Community sample recruited from 3 suburban newborn nurseries (a teaching hospital, community hospital, and large health maintenance organization).One hundred ninety-one healthy full-term infants.Assessment of feeding practices through the ages of complete weaning from breast- and bottle-feeding.More than 90% of participants breast-fed for at least 2 weeks. Infants of older mothers were weaned from the breast later than infants of younger mothers. First-born infants were weaned from the breast earlier than later-born infants. Eighty-four percent of infants bottle-fed at some time during the first year of life. More than 40% of the cohort was still receiving bottles at 24 months of age, 16% at 36 months, and 8% at 48 months. The duration of breast- and bottle-feeding was related to maternal work status; mothers who returned to work during the first 3 months postpartum weaned sooner from the breast and later from the bottle than women who returned to work after 3 months postpartum.The frequency of late bottle-weaning in this well-educated, middle-class cohort was unexpected and was related to the timing of the mother's return to work. The impact of prolonged bottle-feeding on later growth and adiposity deserves further investigation.

    View details for Web of Science ID 000078473900012

    View details for PubMedID 9988250

  • Prospective study of risk factors for the initiation of cigarette smoking JOURNAL OF CONSULTING AND CLINICAL PSYCHOLOGY Killen, J. D., Robinson, T. N., Haydel, K. F., Hayward, C., Wilson, D. M., Hammer, L. D., Litt, I. F., Taylor, C. B. 1997; 65 (6): 1011-1016


    Risk factors for the initiation of cigarette smoking were examined in 2 consecutive cohorts of teenagers (N = 1,901). Students in Cohort 1 were followed over 4 years from 9th to 12th grade; those in Cohort 2 were followed over 3 years from 9th to 11th grade. Among girls with no history of smoking at baseline, those with more friends who smoked at baseline (p < .001) and those with higher sociability scores (p < .05) were significantly more likely to have tried smoking over the study interval. Among boys with no history of smoking at baseline, those with more friends who smoked at baseline (p < .05) and those with higher depression symptoms scores (p < .01) were significantly more likely to have tried smoking over the study interval. The data suggest that future research is needed to examine potential gender differences that may have implications for the next generation of smoking-prevention programs.

    View details for PubMedID 9420362

  • Psychiatric risk associated with early puberty in adolescent girls JOURNAL OF THE AMERICAN ACADEMY OF CHILD AND ADOLESCENT PSYCHIATRY Hayward, C., Killen, J. D., Wilson, D. M., Hammer, L. D., Litt, I. F., Kraemer, H. C., Haydel, F., Varady, A., Taylor, C. B. 1997; 36 (2): 255-262


    This study prospectively evaluated the relationship between early puberty and the onset of internalizing symptoms and disorders in adolescent girls.The sample was drawn from 1,463 sixth-, seventh-, and eighth-grade girls who participated in a longitudinal school-based study of growth and development. Pubertal stage was determined by self-assessment of Tanner stage. Psychiatric assessments included self-report instruments and structured diagnostic interviews. Survival methods were utilized for data analysis.Girls with onset of internalizing symptoms were on average 5 months earlier in pubertal development than those who were asymptomatic (p < .001). In addition, girls with earlier maturation (earliest quartile) were more likely to develop internalizing symptoms than were nonearly matures (hazard ratio = 1.8, confidence interval = 1.2, 2.7). In a subsample of girls followed into high school, early-maturing girls were at marginally higher risk (p < .10) for developing internalizing disorders by the study's end. The highest risk for internalizing disorders was for those girls with both early puberty and prior internalizing symptoms (odds ratio = 3.3).Early puberty increases the risk of internalizing symptoms and perhaps internalizing disorders in adolescent girls.

    View details for PubMedID 9031579

  • Ethnicity and body dissatisfaction: Are Hispanic and Asian girls at increased risk for eating disorders? JOURNAL OF ADOLESCENT HEALTH Robinson, T. N., Killen, J. D., Litt, I. F., Hammer, L. D., Wilson, D. M., Haydel, K. F., Hayward, C., Taylor, C. B. 1996; 19 (6): 384-393


    To compare prevalences and correlates of body dissatisfaction among white, Hispanic, and Asian girls.A total of 939 6th and 7th grade girls (mean age 12.4 years) attending four middle schools in northern California completed self-administered assessments of age, ethnicity, desired body shape, parent education levels, mother's and father's body shapes, pubertal stage, and body dissatisfaction. Body dissatisfaction was assessed with the Body Dissatisfaction scale of the Eating Disorder Inventory. Height, weight, triceps skinfold thickness, and waist and hip circumferences were measured by trained examiners.Hispanic girls reported significantly greater body dissatisfaction than white girls, with Asian girls in-between. After adjustment for body mass index (weight/height), normal and overweight white, Hispanic, and Asian girls reported similar levels of body dissatisfaction. However, among the leanest 25% of girls, Hispanics and Asians reported significantly more body dissatisfaction than white girls. Body mass index was the strongest independent predictor of increased body dissatisfaction in all three ethnic groups. Shorter height among white girls and taller height among Asian girls also made significant independent contributions. Parent education level, a measure of socioeconomic status, was not significantly associated with body dissatisfaction.Body dissatisfaction is not limited to white girls in middle and upper socioeconomic strata. These findings suggest Hispanic and Asian girls may be at greater risk for adopting eating disorder behaviors than previously recognized.

    View details for PubMedID 8969369

  • Weight concerns influence the development of eating disorders: A 4-year prospective study JOURNAL OF CONSULTING AND CLINICAL PSYCHOLOGY Killen, J. D., Taylor, C. B., Hayward, C., Haydel, K. F., Wilson, D. M., Hammer, L., Kraemer, H., BLAIRGREINER, A., Strachowski, D. 1996; 64 (5): 936-940


    The authors examined factors prospectively associated with age of onset of partial syndrome eating disorders over a 4-year interval in a community sample (N = 877) of high school-age adolescent girls. Four percent developed a partial syndrome eating disorder over the interval. A measure of weight concerns was significantly associated with onset in a multivariate Cox proportional hazard analysis (p < .001). Girls scoring in the highest quartile on the measure of weight concerns had the highest incidence (10%) of partial syndrome onset, whereas none of the girls in the lowest quartile developed eating disorder symptoms. This finding is consistent with both theoretical and clinical perspectives and may represent a useful step toward the establishment of a rational basis for the choice of a prevention intervention target.

    View details for PubMedID 8916622

  • Predicting onset of drinking in a community sample of adolescents: The role of expectancy and temperament ADDICTIVE BEHAVIORS Killen, J. D., Hayward, C., Wilson, D. M., Haydel, K. F., Robinson, T. N., Taylor, C. B., Hammer, L. D., Varady, A. 1996; 21 (4): 473-480


    We report results of a prospective examination of the influence of outcome expectancy variables and inherited temperaments on the onset of drinking over a 12-month period in a sample of 1,164 high school students. While univariate prospective analysis indicated that drinkers and nondrinkers were different both on measures of outcome expectancy and temperament, multivariate analysis supported, most strongly, a social learning account of the processes influencing the onset and maintenance of drinking behavior in this sample. The multivariate analysis revealed that only expectancies for enhanced social behavior were consistently associated with the onset of drinking from baseline to 12-month follow-up (p < .001). Among all nondrinkers at baseline, those entertaining higher expectancies about the positive effects of alcohol on social interaction were more likely to begin drinking between baseline and follow-up. At present, few, if any, alcohol abuse prevention studies with adolescents have explicitly attempted to alter alcohol expectancies or to establish a link between expectancy and behavior change. Our results suggest that it may be useful to do so.

    View details for PubMedID 8830905

  • SCHOOL REFUSAL IN YOUNG ADOLESCENT GIRLS WITH NONCLINICAL PANIC ATTACKS JOURNAL OF ANXIETY DISORDERS Hayward, C., Taylor, C. B., BLAIRGREINER, A., Strachowski, D., Killen, J. D., Wilson, D. M., Hammer, L. D. 1995; 9 (4): 329-338


    A 15-minute questionnaire was administered to the pediatric housestaff in an academic training program to assess their breastfeeding attitudes, knowledge, and confidence to manage breastfeeding problems. Questionnaires were self-administered and anonymous. The participation rate was 53% (n = 29). Overall, the study participants indicated a supportive attitude toward breastfeeding (2.6 on a 6-point scale where 1 = most supportive and 6 = least supportive). Women agreed more strongly than men that pediatricians should strongly encourage mothers to breastfeed and disagreed more strongly than men that breastfeeding is instinctive. Although supportive of breastfeeding, the housestaff in this study were not knowledgeable regarding breastfeeding management, answering only 53% of the questions correctly. Their self-confidence in this area was appropriately low, with only 14% of the total sample describing themselves as "confident" or "very confident" to manage common breastfeeding problems. Pediatricians-in-training have extremely limited knowledge of breastfeeding management. To be truly supportive of breastfeeding, pediatricians should receive didactic and clinical training in breastfeeding management.

    View details for Web of Science ID A1995QF83000004

    View details for PubMedID 7748583

  • Pursuit of thinness and onset of eating disorder symptoms in a community sample of adolescent girls: a three-year prospective analysis. International journal of eating disorders Killen, J. D., Taylor, C. B., Hayward, C., Wilson, D. M., Haydel, K. F., Hammer, L. D., SIMMONDS, B., Robinson, T. N., Litt, I., Varady, A. 1994; 16 (3): 227-238


    Community-based prospective studies are needed to shed light on mechanisms that may influence development of eating disorders and identify variables that could serve as potential targets for prevention efforts. In this paper we examine level of weight preoccupation and other variables prospectively associated with age of onset of eating disorder symptoms over a 3-year interval in a community sample (N = 939) of young adolescent girls. 3.6% (32/887) experienced onset of symptoms over the interval. Only one factor, a measure of Weight Concerns, was significantly associated with onset (p < .001). Girls scoring in the highest quartile on the measure of Weight Concerns had the shortest survival time (12% incidence by age 14.5) and those scoring in the lowest quartile had the highest survival time (2% incidence by age 14.5; p < .001). This finding is consistent with both theoretical and clinical perspectives and represents one of the first prospective demonstrations of a linkage between weight and body shape concerns and later onset of eating disorder symptoms. An understanding of the independent variables that predispose girls to development of symptoms is a useful step towards the establishment of a rational basis for the choice of a prevention intervention target.

    View details for PubMedID 7833956

  • TIMING AND RATE OF SEXUAL-MATURATION AND THE ONSET OF CIGARETTE AND ALCOHOL-USE AMONG TEENAGE GIRLS ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE Wilson, D. M., Killen, J. D., Hayward, C., Robinson, T. N., Hammer, L. D., Kraemer, H. C., Varady, A., Taylor, C. B. 1994; 148 (8): 789-795


    To test the hypothesis that the patterns of pubertal progression, early vs late puberty and fast vs slow, are associated with the age at which girls start to drink alcohol and smoke cigarettes.The study included 1463 female students, 10.7 to 18.2 years of age, who were assessed five times during the 2.7-year study. Data regarding pubertal stage, alcohol use, and cigarette use were obtained at each assessment. These data were used to calculate two indexes of pubertal development, the age at which the midpoint of puberty was achieved and the rate of progression through puberty, and the ages when each subject first drank, first drank moderate amounts of alcohol, and first smoked.Girls with earlier puberty (midpoint < 12.2 years) first reported drinking any alcohol at a median age of 12.5 years, 0.7 years younger than girls whose puberty was later. Similarly, girls with earlier puberty reported drinking moderate amounts of alcohol at a median age of 13.7 years, 0.9 years younger than girls with later puberty. Girls with earlier puberty further reported first smoking cigarettes at a median age of 12.8 years, 0.6 years younger than girls with later puberty. The rate of pubertal progression was significantly associated only with the age when girls first drank moderate amounts of alcohol.Earlier puberty is associated with a younger age of onset for both drinking and smoking among adolescent girls.

    View details for Web of Science ID A1994PB26400003

    View details for PubMedID 8044254



    Nine hundred thirty-nine 6th and 7th grade girls participated in the baseline phase of a prospective study designed to examine a set of potential risk factors for the development of eating disorders. Of the 939,839 girls (89%) completed the bulimia nervosa section of the Structured Clinical Interview for DSM-III-R disorders. One girl received the diagnosis of bulimia nervosa, another 35 were classified as a symptomatic group. Using analysis of covariance (ANCOVA), controlling for age and stage of sexual maturation, symptomatic and asymptomatic groups were compared on the following measures: Eating Disorders Inventory (EDI), BMI, triceps skinfold thickness, waist-to-hip ratio, depression symptoms (CES-D and DSRS), Restraint Scale, and a measure of family adaptability and cohesion (FACES). Symptomatic girls were more developmentally mature, significantly heavier, reported greater fear of weight gain, experienced greater dysphoria, indicated increased body dissatisfaction, and reported greater feelings of inadequacy and personal worthlessness. Their status on these dimensions may indicate potential vulnerability to eating disorders and, ultimately, suggest the choice of targets for intervention. Our future goal is to conduct the prospective analyses needed to confirm the hypothesized linkages.

    View details for PubMedID 8032350



    This is the first long-term, controlled study evaluating the effectiveness of a prevention curriculum designed to modify the eating attitudes and unhealthful weight regulation practices of young adolescent girls. Nine hundred sixty-seven sixth and seventh-grade girls were randomized to experimental healthy weight regulation curriculum or no-treatment control classes. A prevention intervention was developed around three principal components: (1) Instruction on the harmful effects of unhealthful weight regulation; (2) promotion of healthful weight regulation through the practice of sound nutrition and dietary principles and regular aerobic physical activity; (3) development of coping skills for resisting the diverse sociocultural influences that appear linked to the current popular obsessions with thinness and dieting. The intervention failed to achieve the hoped-for impact. We did observe a significant increase in knowledge among girls receiving the intervention and among high-risk students only, there was a small albeit statistically significant effect on body mass index. These findings question the wisdom of providing a curriculum directed at all young adolescents, most of whom are not at risk to develop an eating disorder. Rather than targeting the entire population, a healthy weight curriculum designed to modify the eating attitudes and unhealthful weight regulation practices of young adolescent girls might better focus on "at risk" students.

    View details for Web of Science ID A1993KZ50300004

    View details for PubMedID 8490639



    To examine the relationships between hours of television viewing and adiposity and physical activity among female adolescents, a cohort study with follow-up assessments 7, 14, and 24 months after baseline was conducted. All sixth- and seventh-grade girls (N = 971) attending four northern California middle schools were eligible to participate. Six hundred seventy-one students had sufficient data for baseline cross-sectional analyses, and 279 students in a no-intervention cohort had sufficient data for longitudinal analyses. The baseline sample had a mean age of 12.4 years and was 43% white, 22% Asian, 21% Latino, 6% Pacific Islander, 4% black, 2% American Indian, and 2% other. Hours of after-school television viewing, level of physical activity, and stage of sexual maturation were assessed with self-report instruments. Height, weight, and triceps skinfold thickness were measured and body mass index (ratio of weight [in kilograms] to height [in meters] squared) and triceps skinfold thickness were adjusted by level of sexual maturity for the analyses. Baseline hours of after-school television viewing was not significantly associated with either baseline or longitudinal change in body mass index or triceps skinfold thickness. Baseline hours of after-school television viewing was weakly negatively associated with level of physical activity in cross-sectional analyses but not significantly associated with change in level of physical activity over time. All results were essentially unchanged when adjusted for age, race, parent education, and parent fatness. Among adolescent girls, television viewing time appears to have only weak, if any, meaningful associations with adiposity, physical activity, or change in either over time.

    View details for PubMedID 8424000



    Although the incidence of first panic attacks appears to peak during adolescence, little is known about which features of adolescence contribute to the risk of a first panic episode. The purpose of this study was to compare the relative importance of age and pubertal stage in explaining the occurrence of panic attacks in adolescents.From a school-based sample of sixth- and seventh-grade girls, 754 subjects completed both a structured clinical interview determining history of one or more panic episodes and a self-assessment of Tanner stages of pubertal development. A multiple logistic regression analysis was performed with panic attack history as the dependent variable and pubertal stage, age, and their interaction as the independent variables.A history of one or more four-symptom panic attacks was found in 5.3% of the girls (N = 40). After age was controlled for, pubertal stage was significantly related to panic attack history. At each age, higher rates of panic attacks were found in the more physically mature girls.Pubertal stage, after adjustment for the effects of age, appears to predict panic attack occurrence in young adolescent girls. Understanding the link between puberty and panic may offer clues regarding the onset and etiology of panic attacks.

    View details for PubMedID 1503139



    Eating behavior must be viewed as a complex phenomenon involving the coordination of motor, cognitive, social and emotional development, all under the regulation of both central and peripheral factors. Eating provides not only the necessary biologic substrate for human growth and normal physiologic function but is strongly involved in the full range of social interaction from the formation of the mother-infant relationship to later social interaction. Eating is associated with a variety of pleasurable and painful affective experiences. The pediatrician, working closely with the parents, can facilitate the development of healthy attitudes toward eating and healthy eating behaviors.

    View details for Web of Science ID A1992HU00400003

    View details for PubMedID 1574350

  • INSULIN-LIKE GROWTH-FACTOR BINDING PROTEIN-3 IN NORMAL PUBERTAL GIRLS ACTA ENDOCRINOLOGICA Wilson, D. M., STENE, M. A., Killen, J. D., Hammer, L. D., Litt, I. F., Hayward, C., Taylor, C. B. 1992; 126 (5): 381-386


    IGFBP-3 concentrations rise in the second decade of life. To test the hypothesis that the stage of pubertal development, independent of chronological age, was associated with these increases we measured serum IGFBP-3 concentrations by radioimmunoassay in 324 sixth and seventh grade girls (12.3 +/- 0.7 years) at the beginning of a multisite school-based health curriculum. The mean (+/- SD) serum IGFBP-3 among the 242 girls with complete data was 4.0 +/- 0.7 mg/l. Pubertal stage was significantly associated with IGFBP-3 (p less than 0.0001, ANOVA). Mean concentrations rose from 3.5 +/- 0.7 mg/l among those with the earliest pubertal stages to 4.2 +/- 0.7 mg/l among the mature girls. IGF-I and IGFBP-3 concentrations were significantly correlated (Spearman's r = 0.43, p less than 0.0001). After controlling for the association between pubertal development and IGFBP-3 concentrations, only the waist/hip ratio, among the various measures of body composition, was significantly associated with IGFBP-3 concentration (Spearman's r = -0.23, p = 0.0002). Likewise, none of the measures of nutrition: intake of total calories, protein, fat and carbohydrate; serum iron; red cell mean corpuscular volume; or cholesterol; were significantly associated with IGFBP-3 concentrations. There was, however, a small, but significant association between IGFBP-3 concentrations and both serum transferrin and blood hemoglobin concentrations. Pubertal stage has a significant impact on IGFBP-3 concentrations and those attempting to utilize IGFBP-3 concentrations during adolescence should be cognizant of the subject's pubertal stage.

    View details for PubMedID 1377853

  • IS PUBERTY A RISK FACTOR FOR EATING DISORDERS AMERICAN JOURNAL OF DISEASES OF CHILDREN Killen, J. D., Hayward, C., Litt, I., Hammer, L. D., Wilson, D. M., Miner, B., Taylor, B., Varady, A., Shisslak, C. 1992; 146 (3): 323-325


    To examine the association between stage of sexual maturation and eating disorder symptoms in a community-based sample of adolescent girls.All sixth- and seventh-grade girls (N = 971) enrolled in four northern California middle schools. MAIN VARIABLES EXAMINED: Pubertal development measured using self-reported Tanner stage and body mass index (kg/m2). The section of the Structured Clinical Interview for DSM-III-R Disorders (SCID) discussing bulimia nervosa was used to evaluate symptoms of bulimia nervosa.Girls manifesting eating disorder symptoms, while not significantly older than their peers without such symptoms, were more developmentally advanced as determined with Tanner self-staging. The odds ratio for the association between sexual maturity and symptoms was 1.8 (95% confidence interval, 1.2 to 2.8); ie, at each age, an increase in sexual maturity of a single point was associated with a 1.8-fold increase in the odds of presenting symptoms. The odds ratio for the association between body mass index (adjusted for sexual maturity) and symptoms was 1.02 (95% confidence interval, 1.0 to 1.05). There was no independent effect of age or of the interaction between age and the sexual maturity index.These results suggest that (1) puberty may be a risk factor for the development of eating disorders, and (2) prevention efforts might best be directed at prepubertal and peripubertal adolescents.

    View details for Web of Science ID A1992HG92400016

    View details for PubMedID 1543180

  • Advances in behavioral pediatrics Current opinion in Psychiatry Hammer, L. 1992; 5 (6): 840-844


    Large variations in nutritional intake have profound effects on the GH-insulin-like growth factor-I (IGF-I) axis in children and adults, but the effect of normal variations in nutrition on IGF-I concentrations is largely unstudied, particularly during puberty. We measured serum IGF-I concentrations in 325 sixth and seventh grade girls (12.4 +/- 0.7 yr) at the beginning of a multisite school-based health curriculum. The mean serum IGF-I level among the 243 girls with complete data was 573 +/- 244 micrograms/L. Pubertal stage was significantly associated with IGF-I (P less than 0.0001, by analysis of variance). Mean concentrations rose from 427 +/- 198 micrograms/L among those at the earliest pubertal stages to 639 +/- 219 micrograms/L among the mature girls. After adjusting for the association with the stage of pubertal development, serum IGF-I was not significantly associated with measures of body composition (body mass index, triceps skin fold thickness, waist/hip ratio, height, and weight). Additionally, IGF-I concentrations were not associated with nutritional intake (total calories, total protein, total fat, and total carbohydrate) or such measures of nutrition as serum iron, hemoglobin, red cell mean corpuscular volume, white cell count, and cholesterol. IGF-I concentrations, however, were significantly correlated with transferrin concentrations, another possible index of nutritional status (r = 0.29; P less than 0.0001). IGF-I is not a clinically useful index of nutritional status among normal pubertal girls.

    View details for PubMedID 1890162



    Variation in the waist/hip ratio (WHR) may be related to changes in hormonal secretion associated with pubertal maturation. We therefore studied the effects of race, pubertal development, and body fatness on WHR during adolescence in a multiethnic population. A total of 688 white, Asian, and Hispanic female adolescents (mean (+/- SD) 12.4 +/- 0.7 years), participating in the evaluation of a multisite school-based health education program, were included in these analyses. Self-assessed stage of puberty and measurements of height, weight, waist circumference, and hip circumference were obtained from each participant. The WHR and age-adjusted body mass index were calculated. Analysis of covariance demonstrated that puberty significantly affects hip circumference and WHR but not waist circumference among female adolescents. Age and fatness, as reflected by age-adjusted body mass index, contributed significantly to both circumferences and to the WHR. There was a significant effect of ethnicity on hip circumference but not on waist circumference or the WHR. These results confirm that pubertal stage exerts a significant effect on the hip circumference and WHR in female adolescents, even after the effects of fatness and age are controlled. Studies of body fat distribution during late childhood and adolescence should include assessments of pubertal maturation.

    View details for PubMedID 2040937



    Weight-for-height indexes are often used in the clinical assessment of obesity in children and adolescents. The direct measurement of adiposity, using hydrostatic weighing and other techniques, is not feasible in studies involving young children or with large numbers of older subjects. Ratios of weight relative to height, such as the body-mass index (weight/height), may be used as indirect measures of obesity and correlate with more direct measures of adiposity. Using data from the First National Health and Nutrition Examination Study, 1971 to 1974, standardized percentile curves of body-mass index for white children and adolescents were developed. These curves may be used to monitor the body-mass index of white children and adolescents longitudinally and for comparing an individual with others of the same sex and age.

    View details for PubMedID 1750869

  • INFLUENCE OF EARLY FEEDING STYLE ON ADIPOSITY AT 6 YEARS OF AGE JOURNAL OF PEDIATRICS Agras, W. S., Kraemer, H. C., Berkowitz, R. I., Hammer, L. D. 1990; 116 (5): 805-809


    In a previous study we found that a vigorous infant feeding style measured in the laboratory at 2 and 4 weeks of age predicted the degree of adiposity at 1 and 2 years of age. A follow-up of this cohort of infants at 3 and 6 years of age is now reported. Factors predicting adiposity, measured by body mass index at 3 years of age, were pressure of suckling, with high-pressure sucking (denoting a vigorous feeding style) associated with greater adiposity, and time of introduction of solid food, with delayed introduction of solid food or breast-feeding longer than 5 months, or both, being associated with greater adiposity. Predictive factors at 6 years of age were adiposity at birth, with greater adiposity at birth predicting greater fatness at 6 years, parental education, with less education associated with fatness, and a prolonged period of breast-feeding with delayed introduction of solid food. These factors accounted for 40.4% of the variance in adiposity at 3 years of age and 31.2% at 6 years. The effects of social learning on body mass index, indicated by parental educational level, appear to strengthen over time, whereas the effects of the vigorous feeding style wane.

    View details for Web of Science ID A1990DC16500028

    View details for PubMedID 2329430

  • EFFECTS OF PUBERTAL DEVELOPMENT ON WAIST-HIP RATIO (WHR) Wilson, D. M., Hammer, L. D., Litt, I. F., Killen, J. D., Taylor, C. B., Hayward, C., Miner, B., VOSTI, C. NATURE PUBLISHING GROUP. 1990: A8–A8
  • EFFECTS OF PUBERTAL DEVELOPMENT ON WAIST-HIP RATIO (WHR) Hammer, L. D., Wilson, D. M., Litt, I. F., Killen, J. D., Taylor, C. B., Hayward, C., Miner, B., VOSTI, C. SLACK INC. 1990: A163–A163


    Alcohol is a frequently abused drug among adolescents. In adults, alcohol alters iron metabolism, predisposing to excess hepatic iron storage and, possibly, liver damage. The purpose of this study was to determine whether alcohol is associated with an elevated serum iron concentration and transferrin saturation in adolescents, and to determine the contribution of oral contraceptive use to these abnormalities. Adolescents (591 male and 614 female) aged 16 to 19 years, who participated in the first National Health and Nutrition Examination Survey from 1971 to 1973, were grouped according to their reported frequency of alcohol intake. Drinking frequency was associated with serum iron concentrations in boys and girls, and with total iron-binding capacity, transferrin saturation, and hemoglobin concentration in boys. Alcohol use was associated with an elevated serum iron concentration only in oral contraceptive nonusers. Adolescents who use alcohol have an elevated serum iron concentration, and male alcohol users have an increased transferrin saturation as well. These abnormalities may be precursors of hepatic iron overload and chronic liver damage.

    View details for Web of Science ID A1988L894300024

    View details for PubMedID 3341315



    Using data from the large number of adolescents studied in cycle III of the National Health Examination Survey, we utilized a sexual maturity index to develop a set of growth curves that reduce the distortion caused by commingling height data from adolescents maturing at different rates. We also created a set of correction tables to be used with these curves to permit the calculation of an adjusted height percentile that compensates for the effects of the differing rates of pubertal maturation. These adjusted height percentiles should remain more constant throughout puberty than height percentiles obtained from traditional growth curves; they may thus be used to estimate final adult height with only data obtained during routine physical examinations, by assuming that subjects maintain their adjusted height percentile through adolescence to adulthood. Height predictions made in this manner compare favorably with predictions made using two clinically tested algorithms.

    View details for Web of Science ID A1987H069200039

    View details for PubMedID 3578172

  • DOES A VIGOROUS FEEDING STYLE INFLUENCE EARLY DEVELOPMENT OF ADIPOSITY JOURNAL OF PEDIATRICS Agras, W. S., Kraemer, H. C., Berkowitz, R. I., Korner, A. F., Hammer, L. D. 1987; 110 (5): 799-804


    A prospective study of a cohort of healthy infants observed from birth to 2 years of age was carried out to investigate factors influencing the development of early adiposity. Infant suckling was measured in the laboratory twice during the first month of life. Multiple regression analyses revealed that parental educational level and a measure of feeding behavior, the interval between bursts of suckling, accounted for 18% of the variance in triceps skinfold measures at 1 year of age. A lower level of education and shorter interburst interval were associated with increased adiposity. Two feeding variables, pressure of suckling and the number of reported feeds per day, accounted for 21% of the variance in skinfold thickness at 2 years of age. Fewer, but larger, feeds and a higher sucking pressure were associated with a greater degree of adiposity. It seems that a vigorous infant feeding style, consisting of sucking more rapidly, at higher pressure, with a longer suck and burst duration, and a shorter interval between bursts of sucking, is associated with higher caloric intake and greater adiposity. The early development of this feeding style suggests that it may be a genetically endowed behavior. Breast-feeding protected against early adiposity only to the age of 6 months in this cohort of infants.

    View details for Web of Science ID A1987H158300029

    View details for PubMedID 3572635

  • GROWTH AND INTELLECTUAL-DEVELOPMENT PEDIATRICS Wilson, D. M., Hammer, L. D., Duncan, P. M., DORNBUSCH, S. M., Ritter, P. L., Hintz, R. L., Gross, R. T., Rosenfeld, R. G. 1986; 78 (4): 646-650


    Data from the National Health Examination Survey (cycles II and III) provided a representative sample of 13,887 US youths (6 to 17 years of age) with which to examine the relationship between height (normalized for age and sex) and measures of intellectual development (Wechsler Intelligence Scale for Children) and academic achievement (Wide Range Achievement Test). Additionally, 2,177 subjects were studied first in cycle II and 2 to 5 years later in cycle III, forming a well-selected longitudinal study group in which to examine any association between linear growth and change in IQ scores. Wechsler Intelligence Scale for Children and Wide Range Achievement Test scores were significantly correlated with height in both cycle II and cycle III. However, no significant association between change in relative height and change in IQ scores could be detected in the longitudinal group. These data suggest that therapies designed to increase height are unlikely to alter measures of intellectual development or academic achievement.

    View details for Web of Science ID A1986E252900018

    View details for PubMedID 3763275

  • ADIPOSE-TISSUE THYMIDINE KINASE-ACTIVITY IN MAN PEDIATRIC RESEARCH Baum, D., BECK, R. Q., Hammer, L. D., Brasel, J. A., Greenwood, M. R. 1986; 20 (2): 118-121


    Thymidine kinase activity was studied during human adipose tissue development. Adipose tissue was obtained from the groin in 81 persons, aged 7 wk through 60 yr. None had a metabolic or growth disorder. Adipose tissue thymidine kinase activity was highest in infants and lowest in adults. Peak thymidine kinase activity was seen in the early postnatal period and a lesser elevation was found in the preadolescent years, coinciding with hypothesized periods of proliferation of preadipocytes in man. In contrast, during adulthood, a time of stable lipid-laden cell number, thymidine kinase activity was lower. Although these adipose tissue samples include both stromal and fat cells, the data support the hypothesis that adipose tissue growth in early infancy is primarily the result of cellular proliferation, and that little cellular proliferation occurs after infancy, except possibly for a brief period prior to adolescence.

    View details for Web of Science ID A1986AYE4700004

    View details for PubMedID 3945522

  • GROWTH-CURVES FOR ADOLESCENTS WITH EARLY OR LATE MATURATION Wilson, D. M., Ritter, P. L., Kraemer, H. C., Hammer, L. D. SLACK INC. 1986: A2–A2


    Children with accidental ingestions exhibit excessive hand-to-mouth behavior. In a lead-burdened environment, hand-to-mouth behavior contributes to increased lead absorption. To test the hypothesis that accidental-ingestion patients experience greater lead absorption than other urban children, 95 children under 6 years of age with recent ingestions of nonlead-containing materials and a matched control group were compared. Ingestors had higher mean blood lead levels than controls (25.0 micrograms/dl versus 22.2 micrograms/dl, P = 0.036) and higher mean erythrocyte protoporphyrin levels (40.6 micrograms/dl versus 28.6 micrograms/dl, P = 0.006). Ingestion victims were more than three times as likely as controls to be classified as having increased lead absorption. Thumb-sucking was twice as common among ingestors as controls (37% versus 19%). These findings indicate that children with accidental ingestions are at greater risk of increased lead absorption than other urban children.

    View details for Web of Science ID A1985ALX9200004

    View details for PubMedID 4004998