Body size estimation and other psychosocial risk factors for obesity onset among US adolescents: findings from a longitudinal population level study.

Abstract

The purpose of this study was to examine the longitudinal effects of body size over- and underestimation and other psychosocial factors on the risk for onset of overweight (OW) or obesity (OB) 1 year later among US adolescents. Participants with non-missing height and weight were drawn from the first two waves of the National Longitudinal Study of Adolescent to Adult Health (n=13,568). Multinomial logistic regressions were conducted to assess longitudinal risk factors for OW and OB onset, controlling for baseline weight status, age, race/ethnicity, parent education and family structure. Analyses were stratified by sex. Compared with accurate body size perception, body size overestimation increased the relative risk (RR) of OW onset among women and men (RR=3.34, confidence interval (CI)=2.39-4.68; RR=6.01, CI=4.09-8.83, respectively, P<0.001) in fully adjusted models including body mass index z-scores. Body size underestimation decreased the RR of OW onset among women and men (RR= 0.08, CI=0.03-0.20; RR=0.13, CI=0.06-0.27, respectively) and OB onset (RR=0.05, CI=0.02-0.14; RR=0.19, CI=0.08-0.47, respectively, P<0.001 for all) in fully adjusted models. Dieting, extreme weight loss behaviors and skipping breakfast at Wave 1 increased the risk of OB onset by Wave 2. Contrary to a common assumption, body size underestimation did not increase, but in fact decreased, the RR for the onset of OW and of OB among adolescents using a prospective longitudinal design. However, body size overestimation predicted onset of OW 1 year later. Body size self-concept and other psychosocial factors have an important role in risk for OW and for OB among both males and females during adolescence.