Underestimation of adolescent obesity

Previous studies assessing the validity of adolescent self-reported height and weight for estimating obesity prevalence have not accounted for, potential bias due to nonresponse in self-reports.

The aim of this study was to assess the implications of selective nonresponse in self-reports of height and weight for estimates of adolescent obesity.

The authors analyzed 613 adolescents ages 12-17 years from the 2006-2008 Los Angeles Family and Neighborhood Survey, a longitudinal study of Los Angeles County households with an oversample of poor neighborhoods. Obesity prevalence estimates were compared based on (a) self-report, (b) measured height and weight for those who did report, and (c) measured height and weight for those who did report.

Among younger teens, measured obesity prevalence was higher for those who did not report height and weight compared with 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 nonresponse) versus 9 percentage points (when nonresponse was not accounted for). Results were robust to the choice of difference child growth references.

Adolescent obesity surveillance and prevention efforts must take into account selective nonresponse for self-reported height and weight, particularly for younger teens. Results should be replicated in a nationally representative sample.