Self-reported weight and height: Implications for obesity research

Background: Self-reported weight and height are under- and over-reported, respectively, in epidemiologic studies. This tendency, which may adversely affect study operations, has not been evaluated among subjects being enrolled into a weight-loss program. Methods: Self-reported weight, height, and body mass index (BMI) were compared to measured values in 97 overweight or obese (BMI>27.3) women being enrolled into a randomized, controlled trial of two behavioral interventions for weight loss. The effects of demographic factors, baseline weight, baseline height, and baseline BMI on weight and height reporting were assessed. Results: There was a significant difference between measured and reported weight (mean DIFFERENCE=−3.75 lb, p=0.0001) and height (mean DIFFERENCE=+0.35 in., p=0.0007). The mean difference between measured and reported BMI was −1.14 kg/m2 (p=0.0001). Unemployed, retired, or disabled women were more likely to under-report their BMI than employed women (p=0.001). Six percent of subjects who were initially considered eligible for the study on the basis of the self-report were eventually excluded from the study because they did not meet the inclusion criterion for BMI. Conclusion: Obese women who seek weight-loss assistance tend to under-report their weight and over-report their height, suggesting that self-reported data are likely to be inaccurate. Misreporting is apparently influenced by employment and disability and has the potential to complicate recruitment of subjects for research studies.