Association of smoking with risk of stroke in middle-aged and older Chinese: Evidence from the China National Stroke Prevention Project.

Although the impacts of smoking on health are well established, it is unclear on how they affect the Chinese population aged ≥40 years. This study aimed to investigate the association between smoking and risk of stroke in middle-aged and older Chinese adults, based on the data from the China National Stroke Prevention Project.A community-based cross-sectional study with 12,704 (5681 men, 7023 women) Chinese adults aged ≥40 years was conducted to examine the association of smoking with stroke. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).Among the study population, a total of 524 stroke survivors were identified. The age-adjusted prevalence of stroke was 4.06% for both sexes, 2.95% for women, and 5.38% for men. The multivariate-adjusted ORs (95% CI) of stroke associated with current cigarette smoking and former cigarette smoking were 1.67 (1.24-2.25) and 1.93 (1.29-2.87), respectively. Compared with those who were never-smokers, the multivariate-adjusted OR of stroke (95% CI) were 1.48 (0.96 to -2.29), 1.75 (1.20-2.56), and 2.37 (1.20 to -4.68) for those who smoked 1 to 10, 11 to 20, and ≥21 cigarettes per day; and 0.51 (0.19 to -1.42), 1.90 (1.36 to -2.67), and 2.01 (1.17 to -3.46) for those who smoked 1 to 19, 20 to 39, and ≥40 years, respectively (both P < .001 for linear trends). Among former smokers, the multivariable-adjusted ORs of stroke by duration of smoking cessation (compared with never smokers) for <5, 5 to 19, and ≥20 years were 3.47 (1.42-8.49), 3.37 (1.95-5.80), and 0.95 (0.49-1.84), respectively (P = .009 for linear trend). The increased odds of stroke with smoking were more evident among participants who were men, >60 years old, or without family history of stroke than their counterparts.This study suggests the increased odds of stroke in current cigarette smokers with a graded increase in prevalent risk that depended on how many cigarettes and how many years were smoked. Moreover, quitting smoking appears to decrease this excess risk substantially.