Association of lifespan reproductive duration with depression in Swedish twins: The role of hormone replacement therapy

ObjectiveTo examine the association between reproductive duration and postmenopausal depression (taking the use of hormone replacement therapy [HRT] into account). MethodsIn this population-based cohort study, 11 320 postmenopausal women (mean age 63.6 years) were followed for up to 18 years. Reproductive duration was categorized into three groups: short (<= 34 years), average (35-39 years), and long (>= 40 years). Depression was ascertained from the Sweden National Patient Registry. ResultsDuring the follow up, 593 (5.24%) women developed depression. In the multi-adjusted generalized estimating equation model, the odds ratios (ORs) of depression were 1.28 (95% confidence interval [CI] 1.05-1.55) and 1.25 (95% CI 1.01-1.55) for women with short and long reproductive durations, respectively, compared with those women with average reproductive duration. Women with a non-typical reproductive duration (<= 34 or >= 40 years) who received HRT were at a higher risk of depression (OR 1.82, 95% CI 1.42-2.33). There was a significant additive interaction between non-typical reproductive duration and the use of HRT on depression (attributable proportion 0.26, 95% CI 0.03-0.50). ConclusionWomen with a short or long reproductive duration, especially those with a history of HRT use, have a higher risk of depression after menopause compared with those with an average reproductive duration.