Reliability of reported age at menopause.

Age at menopause is an important epidemiologic characteristic whose reliability of reporting in the US population is not known. The authors examined four hypotheses about the reliability of reported age at menopause in the United States: 1) women with hysterectomy-induced menopause more reliably report their age at menopause than women who have undergone natural menopause; 2) reliability declines with time since menopause; 3) reliability declines with age; and 4) women with higher educational levels report their age at menopause more reliably than women with less education. The authors used linear regression models among 2,545 women in the First National Health and Nutrition Examination Survey and Followup Study (1971-1984) and compared responses at first and follow-up interviews. Among women who had undergone a natural menopause, 44% reported their age at menopause within one year from the first to second interviews; among women who had undergone a hysterectomy-induced menopause, 59% reported their age at menopause within one year from first to follow-up interviews. Only hysterectomy status and years from menopause to follow-up interview were significantly associated with the absolute difference between age at menopause reported at first and follow-up interviews. The authors conclude that caution in studies involving age at menopause may enhance our understanding of this critical event in the lives of women.