Reliability of self-reported weight at age of 18 and self-reported age at menarche and menopause

Background: In population-based studies, weight and height are often self-reported. The self-report of these anthropometrics is known to be biased (1). The aim of our study is to evaluate the reliability of self-reported weight at age of 18 and self-reported age at menarche and menopause, and to determine to what extent the reliability was affected by age and education. Methods: A total of 354 women (20–83 years, mean age 54.8+11.5) reported their weight and age in a questionnaire at baseline and at follow-up (mean difference: 30 month). Bland Altman plots were used for the reliability analyses, while linear regression analyses were performed to assess the factors that were independently associated with the reliability (measured by absolute differences). Results: Weight at age of 18 and age at menarche and menopause were reported on average with small bias (mean weight difference: 0.1kg; mean age difference at menarche: 0.02 years, and at menopause: 0.05 years).However, some subgroups showed considerable differences. The differences in self-reported weight and age by menarche and menopause were greater in women with lower education. Furthermore self-reported weights were related to age – the difference increased with increasing age (0.5kg per 10 year increment; 95% KI: 0.11–0.89kg). Discussion: On average, women in this study were generally quite capable to report their weight at age of 18 and age at menarche and menopause with good reliability. However, in subgroups of elderly women and women with lower education, we found greater differences. The level of education was inversely related to the reliability of weight information. These findings are consistent with former studies. BMBF-Förderkennzeichen: 01ZP0507