Underestimation of Adolescent Obesity

Abstract

Background— Previous studies assessing the validity of adolescent self-reported height and weight for estimating obesity prevalence have not accounted for potential bias due to non-response in self-reports. Objectives— The purpose of this study was to assess the implications of selective non-response in self-reports of height and weight for estimates of adolescent obesity. Methods— The authors analyzed 613 adolescents ages 12-17 from the 2006-08 Los Angeles Family and Neighborhood Survey, a longitudinal study of Los Angeles County households with an oversample of poor neighborhoods. Obesity prevalence estimates based on (1) self-report, (2) measured height and weight for those who did report, and (3) measured height and weight for those who did not report were compared. Results— Among younger teens, measured obesity prevalence was higher for those who did not report height and weight compared to those who did (40% vs. 30). Consequently, obesity prevalence based on self-reported height and weight underestimated measured prevalence by 12 percentage points (when accounting for non-response) vs. 9 percentage points (when non-response was not accounted for). Results were robust to the choice of difference child growth references (i.e,, CDC vs. International Obesity Task Force). Discussion— Adolescent obesity surveillance and prevention efforts must take into account selective non-response for self-reported height and weight, particularly for younger teens. Results should be replicated in a nationally-representative sample.