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.