Different Types of Family History of Stroke and Stroke Risk: Results Based on 655,552 Individuals.

Background: Many studies concentrated on the relationships between different types of family history and stroke, but they have not arrived at an unified conclusion. We conducted a comprehensive systematic review to further evaluate the associations.

Methods: Different databases were searched for related studies published from 1990 to August 2017. The relative risk was considered as the common measure of association across different studies. Heterogeneity of effects across studies was quantified by I.

Results: Sixteen published studies (total participants: 655,552) were eligible in this study. The pooled multifactorial adjusted relative risk (RR) (95% confidence interval [CI]) was 1.40 (1.18, 1.67) for individuals with paternal history, 1.36 (1.20, 1.53) for those with maternal history, and 1.44 (1.17, 1.77) for those with sibling history. Based on cohort studies, the pooled adjusted RRs (95%CIs) for paternal, maternal, and sibling history were 1.33 (1.11-1.59), 1.28 (1.14-1.45), and 1.24 (1.01-1.51), respectively, all of which were smaller than those based on case-control and cross-sectional studies. In studies with large sample size, the respective adjusted RR (95%CI) of stroke for paternal, maternal, and sibling history was 1.30 (1.09, 1.56), 1.30 (1.18, 1.44), and 1.26 (1.02, 1.56), which was lower than that in studies with small sample size.

Conclusions: Each type of family history of stroke was associated with an increased stroke risk. We could not find significant differences among stroke risks relating to different types of family history of stroke. Thus, paternal, maternal, and sibling history require our equal attention in the stroke prevention and control work.