Figure 1.

Subgroup analysis of associations between family history and ischemic stroke according to baseline smoking characteristics. Hazard ratios for ischemic stroke are for comparison of men and women who had a family history of stroke with those who had no family history of stroke. Ever-regular smokers excludes occasional smokers (n=22,620) and ex-smokers who stopped by choice (n=13,141). Tests for heterogeneity include only ever-regular smokers. Horizontal lines represent 95% confidence intervals.