Population attributable fraction of stroke incidence in middle-aged and elderly people: contributions of hypertension, smoking and atrial fibrillation.

We determined the population attributable fraction (PAF) of stroke due to hypertension (HT), atrial fibrillation (Af) and smoking in a Japanese community. Residents of Shibata (n = 2,302) who were surveyed initially in 1977 were followed until 1997. Two hundred and thirteen first strokes occurred. Among those 40-64 years of age, the risk ratio (RR) of Af was 11.24, followed by untreated HT (3.61), uncontrolled HT (3.69) and smoking (1.84). The PAFs, however, were 14.9% for smoking, 13.5% for untreated HT, 8.6% for uncontrolled HT and 3.6% for Af. Among those over 65 years, only Af was significant (RR 3.89) and the PAF was 6.0%. Determination of PAFs is also essential for designing effective stroke prevention programs in communities. Copyright 2000 S. Karger AG, Basel