Comparison of self-reported and measured height and weight in eighth-grade students

The goal of this study was to evaluate the relationships between self-reported and measured height, weight, and body mass index (BMI) in a sample of eighth-grade students. The study population consisted of eighth-grade students in eastern North Carolina who completed a cross-sectional survey, self-reported their height and weight, and had their height and weight measured (N = 416). Fifty-nine percent of the sample was male; 42% African American, 46% white, and 12% other races. Mean self-reported weight (62.9 kg) was significantly lower than mean measured weight (64.4 kg). Mean self-reported BMI (22.8 kg/m2) was significantly lower than mean measured BMI (23.3 kg/m2). Race and BMI category were significantly associated with reporting errors. Specifically, African American and white students were significantly less likely to under-report their height compared to other race students. African American students were more likely to underestimate their weight compared to other race students. BMI was more likely to be underestimated in African American and white students compared to other race students. Students who were at risk for overweight and those that were overweight were more likely to underestimate their weight and BMI than students who were normal weight. Approximately 17% of students were misclassified in BMI categories when self-reported data were used. The results indicate that eighth-grade students significantly underestimate their weight, but on average provide valid estimates of their height. Race and measured BMI category influence this discrepancy. School-based research that addresses the prevalence of obesity in adolescents should utilize measured height and weight when feasible.