Female reproductive factors and the likelihood of reaching the age of 90 years. The Netherlands Cohort Study

Objectives The aim of this study was to prospectively assess the relationship between several reproductive factors in women and the likelihood of reaching the age of 90 years (achieving longevity). Study design For this study, data from the oldest birth cohort (1916-17) of the prospective Netherlands Cohort Study (NLCS) were used. These participants filled in a baseline questionnaire in 1986 (at age 68-70 years). Follow-up for vital status information until the age of 90 years (2006-07) was >99.9% complete. Main outcome measures Multivariable-adjusted Cox regression analyses with a fixed follow-up time were based on 2,697 women with complete exposure and co-variable data to calculate risk ratios (RR) of reaching age 90. Results No associations were observed between the likelihood of reaching the age of 90 years, and age at menarche, age at menopause, parity, menstrual lifespan, and oral contraceptive use after adjustment for potential confounders. A later age at first childbirth pointed towards a higher chance of achieving longevity (age ≥30 vs. 20-24; RR,1.17; 95%CI,0.98-1.39). Ever-use of hormone replacement therapy (HRT) was significantly associated with a higher chance of achieving longevity compared with never HRT-users, but only in women who had had an early menopause (<50 years)(RR,1.32; 95% CI, 1.07-1.61). Conclusion Age at first childbirth, and ever-use of HRT in women with an early menopause (<50 years) were associated with the likelihood of reaching the age of 90 years.