Cigarette Smoking and Risk of Incident Rosacea in Women.

The relationship between smoking and rosacea is poorly understood. We aimed to conduct the first cohort study to determine the association between smoking and risk of incident rosacea. We included 95,809 women from Nurses' Health Study II (1991-2005). Information on smoking was collected biennially during follow-up. Information on history of clinician-diagnosed rosacea and year of diagnosis was collected in 2005. We used Cox proportional hazards models to estimate age- and multivariable-adjusted hazard ratios and 95% confidence intervals for the association between different measures of smoking and risk of rosacea. During follow-up, we identified 5,462 incident cases of rosacea. Compared with never smoking, we observed an increased risk of rosacea associated with past smoking (multivariable-adjusted hazard ratio = 1.09, 95% confidence interval: 1.03, 1.16) but a decreased risk associated with current smoking (hazard ratio = 0.65, 95% confidence interval: 0.58, 0.72). We further found that increasing pack-years of smoking was associated with an elevated risk of rosacea among past smokers (P for trend = 0.003) and with a decreased risk of rosacea among current smokers (P for trend < 0.0001). The risk of rosacea was significantly increased within 3-9 years since smoking cessation, and the significant association persisted among past smokers who had quit over 30 years before.