Errors in body mass index from self-reported data by sex and across waves of Add Health

Abstract

PurposeBody mass index (BMI) derived from self-reported height and weight is often used to study adiposity and its health implications. However, misestimates of BMI from self-reported data have been observed. This study adds to the literature by demonstrating how anthropometric misreporting patterns differed by sex and changed across time in a nationally representative cohort, as well as examining behavioral/psychological correlates of biases in BMI. MethodsMisreporting of height and weight (and thus BMI) from adolescence to adulthood in the United States was studied using the National Longitudinal Study of Adolescent to Adult Health (1996–2008). Behavioral/psychological characteristics possibly associated with errors in BMI were analyzed with fixed-effects models. ResultsDifferent patterns of anthropometric misreporting resulted in larger underestimation of BMI among females than males at the beginning waves, but females saw a reduction by the last wave. Males did not see such a decrease, and their error, at 0.75 BMI units by 2008, was comparable to that of females. For both sexes, body image perception was a significant predictor of biases in BMI. ConclusionsFrom adolescence to adulthood, anthropometric reporting patterns changed, and its variation differed by sex. Nevertheless, errors in BMI were similarly associated with behavioral/psychological characteristics.