Pregnancy-related factors and the risk of isolated systolic hypertension

Background. Isolated systolic hypertension (ISH) is known to be a strong predictor of cerebrovascular and cardiac events, especially in women. Metabolic and hormonal changes associated with reproductive history may contribute to the development of cardiovascular diseases. The aim of this study was to identify associations between pregnancy-related factors and ISH. Methods. A cross-sectional study based on a random sample of 3937 Finnish women aged 30-99 was carried out. Associations between pregnancy-related factors and ISH were analyzed using multivariate analyses. Results. Of 3470 subjects, 26% had ISH. Younger age at first delivery predicted a higher risk of ISH (odds ratio after adjustment for age, education, smoking, height and weight=1.31, 95% CI 1.07-1.61). Age at first and last delivery was significantly associated with age, education, marital status and use at any time of hormone replacement therapy (HRT); age at first delivery was also associated with toxemia in any pregnancy, weight and body mass index (BMI). In the univariate analyses, ISH was significantly associated with age, height, weight, BMI, education, marital status, oral contraceptive pills use at any time and HRT use at any time. Conclusion. This population-based study showed that early age at first delivery increased the risk of ISH, which may in turn increase cerebrovascular and cardiac events after menopause. Age at first delivery is heavily dependent on education, which may be linked to the risk of developing of cardiovascular disease throughout adulthood. The other plausible mechanism may be adiposity due to pregnancy.