Smoking cessation, weight gain, and risk of stroke among postmenopausal women.

The relationship between smoking cessation, concurrent weight gain, and stroke events is not yet understood. Thus, we examined the association between smoking cessation and subsequent stroke risk and whether the association was modified by concurrent weight gain. In 2017, we analyzed data from 109,498 postmenopausal US women enrolled in the Women's Health Initiative from 1993 to 1998. Women with a history of cancer or cardiovascular disease events were excluded. The median length of follow-up time was 14.01 years. Variables of primary focus were smoking cessation, weight change, and clinically confirmed incident cases of hemorrhagic and ischemic stroke. Hazard ratios were estimated for stroke incidences (all, ischemic, and hemorrhagic) associated with smoking cessation using Cox regression. The exposure-outcome relationship of smoking cessation and risk of stroke was evaluated for effect modification by weight change. Recent quitters between baseline and year 3 had a significantly lower risk for all stroke and ischemic stroke, but not hemorrhagic stroke, when compared to the reference group of continuing smokers. In the multivariable-adjusted model for ischemic stroke, the hazard ratio for recent quitters was 0.66 (95% CI: 0.46, 0.95). In the model for hemorrhagic stroke, the hazard ratio for recent quitters was 0.76 (95% CI: 0.36, 1.61). The association between recent quitting and stroke risk was not significantly modified by weight change. Smoking cessation was associated with a significant reduction in stroke risk. The benefit of smoking cessation on the risk of stroke was not attenuated by concurrent weight gain.