Shorter reproductive life span is associated with increased cardiovascular risk and total mortality in Swedish women from an observational, population-based study

Objectives: Reproductive history of women is of importance to estimate cardiovascular disease (CVD) risk. One aspect of that history is the reproductive life span (RLS), the period between onset of menarche and menopause. Previous studies have indicated an increased risk associated with shorter RLS, but this has never previously been tested in Scandinavian women. Our aim was to investigate such associations in Swedish women. Study design: We used observational data from the Malmo Diet Cancer Study (MDCS), which included 12,101 middle-aged women (mean age 60 years at baseline) born between 1923 and 1945 from Malmo, Sweden. Data on reproductive history was obtained from a questionnaire. Main outcome measures: Cox regression was used to estimate the association between quintiles (Q1-Q5) of RLS and incident fatal or non-fatal CVD events and total mortality during follow-up, adjusted for co-variates. Results: During a maximum of 28 years of follow-up, there were 2678 non-fatal CVD events and 5697 deaths. A shorter RLS was associated with an increased CVD risk (hazard ratio (HR) 1.19, 95 % confidence interval (CI) 1.06-1.34, p = 0.004) when comparing Q1 (RLS = 32 years) with Q5 (RLS = 40 years). The association remained significant when specifically controlling for history of hysterectomy and/or oophorectomy (HR 1.20, 95% CI 1.07-1.35, p = 0.002, for Q1 vs. Q5). A shorter RLS was also associated with a higher mortality risk (HR 1.21, 95% CI 1.11-1.31, p = 0.001, for Q1 vs. Q5, and HR 1.10, 95% CI 1.02-1.20, p = 0.02, for Q2 vs. Q5). Conclusion: A shorter RLS was associated with increased risk of cardiovascular events and total mortality in Swedish women.