Relationships between family histories of stroke and of hypertension and stroke mortality: NIPPON DATA80, 1980-1999

A family history of stroke seems to be related with increased risk of stroke although the relationship is not always significant. Increased risk of stroke is strongly associated with hypertension, which might be also associated with family history. However, investigations into the relationship between family history of hypertension and stroke mortality are scarce. We investigated whether a family history of stroke and that of hypertension evaluated using a simple questionnaire could predict stroke mortality in Japanese. We obtained parental histories of stroke and of hypertension from 8,037 randomly selected general Japanese without history of cardiovascular disease and followed them for 19 years. The multivariate adjusted hazard ratios (HRs) for total stroke mortality, intra-cerebral hemorrhage mortality and for cerebral infarction mortality according to family history were estimated using the Cox proportional hazards model. The prevalences of family histories of stroke and of hypertension were 20.6% and 31.1%, respectively. A family history of stroke was not related to total stroke mortality, intra-cerebral hemorrhage mortality or to cerebral infarction mortality. Meanwhile, a family history of hypertension was positively related to total stroke mortality among women aged less than 60 years and men aged 60 or more years (women: HR=3.41, 95% confidence interval [CI]: 1.49-7.81; men: HR=1.50, 95% CI: 1.00-2.24) even after adjustment for systolic blood pressure. In conclusion, a family history of stroke could not predict total stroke mortality. However, a family history of hypertension might predict an increased risk for total stroke.