Hypertensive disorders in pregnancy and later dementia: a Swedish National Register Study

Introduction: Our aim was to investigate the rate of vascular dementia and dementia in women with previous hypertensive disorders in pregnancy, since white matter lesions of the brain and cardiovascular disease are linked both to dementia and hypertensive disorders in pregnancy. Material and methods: Prospective population-based registry study on all women giving birth in Sweden between 1973 and 1975 (284 598). Women with and without hypertensive disorders in pregnancy were identified by means of the Swedish Medical Birth Register and linked to the National Patient Register, where data on somatic disease later in life were obtained. International classification of disease was used. The Cox proportional hazard model was used to calculate hazard ratios for both groups and adjusted for possible confounders. Main outcome measures were in-hospital diagnosis of cardiovascular disease, vascular dementia and dementia. Results: No increased risks were seen for vascular dementia or dementia after any hypertensive disorders in pregnancy. If broken down in specific diagnoses for hypertensive disease in pregnancy, adjusted risks for vascular dementia after hypertension and proteinuria during pregnancy the hazard ratio was 6.27 (95% CI 1.65–27.44). Higher risks for cardiovascular disease were confirmed. Conclusions: Because of the very low absolute risk, the wide confidence interval and risk of misclassification, our results on vascular dementia could be questioned. Considering the pathophysiology of preeclampsia, the findings of brain lesions and the increased risk for cardiovascular disease, the possibly increased risk for all kinds of dementia must be investigated in larger and more well-defined cohorts.