Validity of self-reported weight, height, and body mass index among African American breast cancer survivors

Self-reported weight, height, and body mass index (bmi) are commonly used in cancer epidemiology studies, but information on the validity of self-reports among cancer survivors is lacking. this study aimed to evaluate the validity of these self-reported measures among african american (aa) breast cancer survivors, known to have high obesity prevalence. we compared the self-reported and measured values among 243 participants from the women’s circle of health follow-up study (wchfs), a population-based longitudinal study of aa breast cancer survivors. multivariable-adjusted linear regressions were used to identify factors associated with reporting errors. we also examined the associations of self-reported and measured bmi with obesity-related health outcomes using multivariable logistic regressions, with hypertension as an example, to evaluate the impact of misreporting. we found that self-reported and measured values were highly correlated among all and when stratified by participants’ characteristics (intraclass correlation coefficients ≥ 0.99, 0.84, and 0.96 for weight, height, and bmi, respectively). the agreement between bmi categories (normal, overweight and obese) based on self-reported and measured data was excellent (kappa = 0.81). women who were older, never smoked, had higher grade tumors, or had greater bmi tended to have overestimated bmi calculated from self-reported weight and height. the bmi-hypertension association was similar using self-reported (or per 5 kg/m2 increase 1.63; 95% ci 1.27–2.10) and measured bmi (1.58; 95% ci 1.23–2.03). self-reported weight, height, and bmi were reasonably accurate in the wchfs. our study supports the use of these self-reported values among cancer survivors when direct measurements are not possible.