Objective-To identify predictors of becoming eating disordered among adolescents. Design-Prospective cohort study. Setting-Self-report questionnaires.Subjects-Girls (n=6916) and boys (n=5618), aged 9 to 15 years at baseline, in the ongoing Growing Up Today Study (GUTS).Main Exposures-Parent, peer, and media influences.Main Outcome Measures-Onset of starting to binge eat or purge (ie, vomiting or using laxatives) at least weekly.Results-During 7 years of follow-up, 4.3% of female subjects and 2.3% of male subjects (hereafter referred to as "females" and "males") started to binge eat and 5.3% of females and 0.8% of males started to purge to control their weight. Few participants started to both binge eat and purge. Rates and risk factors varied by sex and age group (<14 vs ≥14 years). Females younger than 14 years whose mothers had a history of an eating disorder were nearly 3 times more likely than their peers to start purging at least weekly (odds ratio, 2.8; 95% confidence interval, 1.3-5.9); however, maternal history of an eating disorder was unrelated to risk of starting to binge eat or purge in older adolescent females. Frequent dieting and trying to look like persons in the media were independent predictors of binge eating in females of all ages. In males, negative comments about weight by fathers was predictive of starting to binge at least weekly. Additional Contributions: S. Bryn Austin, ScD, and Ruth Streigel-Moore, PhD, provided comments on preliminary analyses.Author Contributions: Dr Field had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Field, Camargo, and Laird. Acquisition of data: Field and Camargo. Analysis and interpretation of data: Field, Javaras, Aneja, Kitos, and Taylor. Drafting of the manuscript: Field, Kitos, and Taylor. Critical revision of the manuscript for important intellectual content: Field, Javaras, Aneja, Kitos, Camargo, Taylor, and Laird. Conclusions-Risk factors for the development of binge eating and purging differ by sex and by age group in females. Maternal history of an eating disorder is a risk factor only in younger adolescent females.Concerns about weight and body shape are common in preadolescents and adolescents 1,2 and are probably related to the development of unhealthy weight control behaviors and binge eating. However, because of the lack of large prospective studies of non-treatmentseeking samples, little is known with certainty about the development of disordered eating (eg, engaging in bulimic behaviors) or eating disorders.Although there have not been many large prospective studies of disordered eating (ie, engaging in binge eating or purging) or full-criteria eating disorders 3 among non-treatmentseeking samples, a variety of risk factors for disordered eating and eating disorders have been proposed. The support for some of these purported risk factors is stronger than for others. 4 The risk factors with the strongest support, which a...

FIELD, ALISON E., PARUL ANEJA, AND BERNARD ROSNER. The validity of self-reported weight change among adolescents and young adults. Obesity. 2007;15: 2357-2364. Objective: To assess the association of weight change based on serial self-reported vs. measured weights. Research Methods and Procedures: Two thousand two hundred eighty-four male and 2476 female participants in the National Longitudinal Study of Adolescent Health who provided information on weight at Waves II and III and were at least 16 years of age were studied. Linear regression was used to assess predictors of the discrepancy between weight change based on self-reported vs. measured weights. Logistic regression was used to identify predictors of selfreport correctly classifying participants in terms of weight change category. Results: Self-reported weight was slightly lower than measured weight at Waves II and III, but weight change based on self-reported weights underestimated true weight change by only 2.1 (female participants) to 2.8 (male participants) pounds. Overweight and obese female participants were consistent in their under-reporting of their weight more than their leaner peers; thus, the discrepancy between weight change from Wave II to Wave III based on serial selfreports vs. measured weights was significantly smaller among the obese female vs. healthy-weight female participants (0.3-vs. 2.3-pound underestimation, p Ͻ 0.05). Among the male participants, the same pattern was evident.African-American ethnicity, Hispanic ethnicity, the level of physical activity, the hours per week watching television, and weight change efforts were not related to the discrepancy between weight change based on self-reported vs. measured weights. Discussion: The discrepancy between weight change based on self-report vs. measured weights was minor and not related to race, weight change efforts, activity, or inactivity, thus suggesting that much of the error is random.

FIELD, ALISON E., PARUL ANEJA, S. BRYN AUSTIN, LYDIA A. SHRIER, CARL DE MOOR, AND PENNY GORDON-LARSEN. Race and gender differences in the association of dieting and gains in BMI among young adults. Obesity. 2007;15:456 -464. Objective: To assess the relationship between dieting and subsequent weight change and whether the association varies by gender or race/ethnicity. Research Methods and Procedures: Male (n ϭ 4100) and female (n ϭ 4302) participants in the National Longitudinal Study of Adolescent Health who provided information on weight and height at baseline and two follow-up assessments and were not missing information on weight control strategies or race were studied. Generalized estimating equations were used to assess whether dieting to lose or maintain weight at Wave I or II predicted BMI (kg/m 2 ) change between adolescence and young adulthood (Wave II to III). Analyses were stratified by gender and took sampling weights and clustering into account. Results: At Wave I, the mean age of the participants was 14.9 years. Approximately 29.3% of female participants and 9.8% of male participants reported dieting in Wave I or II. Fewer African Americans than whites (6.2% vs. 10.0% and 25.5% vs. 31.2%, p ϭ 0.007 and p ϭ 0.02, among males and females, respectively) reported dieting. Between Waves II and III, participants gained on average 3.3 kg/m 2 . Independent of BMI gain during adolescence (Waves I to II), female participants who dieted to lose or maintain weight during adolescence made larger gains in BMI during the 5 years between Waves II and III (mean additional gain, 0.39 kg/m 2 ; 95% confidence interval, 0.08 to 0

This study examined trajectories of positive and negative affect surrounding penile-vaginal sexual intercourse (sex) in adolescents and explored the influence of companionship on these trajectories. Using a handheld computer, sexually active adolescents (N = 67) reported momentary affect and sex events in response to several random signals each day for 1 week (1,777 reports, 266 sex events). Cubic spline regression analyses showed that positive affect began to increase before sex, peaked at the time sex was reported, and then returned to baseline. Negative affect did not differ from baseline before sex, but decreased following sex. Improvement in affect before and after sex varied according to companionship. Understanding the complex associations of affect, companionship, and sex has implications for interpreting and intervening on adolescent sexual behavior in social context.