Social and environmental conditions across the life course and age at menopause in a British birth cohort study

Objective To assess whether socio-economic status, environmental stress and hardship throughout the life course are associated with age at menopause. Design Birth cohort study. Setting England, Scotland, Wales. Sample A total of 1515 women from a stratified sample of all births in one week in 1946. Methods Age at menopause was collected using annual postal questionnaires from age 47 to 53 years. Information on socio-economic conditions and hardship were collected at contacts throughout life from age 2 to 43 years. Socio-economic indicator variables were defined to represent cumulative exposure to hardship in childhood and in adulthood. Main outcome measures Age at menopause. Results Cox's proportional hazard models indicated that women whose fathers were in a manual social class occupation at three time points during her childhood had an earlier age at menopause than those whose fathers were in non-manual occupations at all three (HR: 1.51; 95% CI: 0.93 - 2.47). Similar findings were seen for household crowding. These socio-economic gradients could not be explained by adult socioeconomic status, behaviour and lifestyle or by psychological health and stress, but were attenuated by other early life factors. Women who experienced parental divorce early in life (before five years of age) had double the rate of menopause of those whose parents did not divorce (HR: 2.14; 95% CI: 1.33 - 3.42). There were no consistent findings with adult socio-economic indicators. Conclusions There is some evidence of a cumulative effect of socio-economic circumstances in childhood, but not in adulthood, on age at menopause. Childhood nutrition, cognition and emotional stress possibly underlie the social gradient.