Validity and reproducibility of self-reported age at menopause in women participating in the DOM-project

Objectives: To study validity and reproducibility of self reported age al menopause. Methods: Subjects were 1003 and 4892 Dutch women respectively aged 58-73, who participated in a population-based breast cancer screening project. The median time since menopause was 7 years for the validity study. The time span between the two questionnaires in the reproducibility study was 7-9 years. Results: Of the women with a natural menopause, 70% recalled their age at menopause correctly to within one year. For women with a surgical menopause this percentage was 80%. The validity decreased with increasing number of years since menopause. Reproducibility to within one pear was 71% for women with a natural menopause and 79% for women with a surgical menopause; 95% of the women were consistent in reporting whether they had had a natural or a surgical menopause. Conclusions: As a consequence of this misclassification, the effect of age at menopause may be underestimated in studies relating self reported age at menopause to disease occurrence or mortality. (C) 1997 Elsevier Science Ireland Ltd.