Cigarette smoking and risk of herpes zoster: a population-based cohort study in Taiwan.

The effects of cigarette smoking on the risk of herpes zoster (HZ) infection remain unclear. This study aimed to examine the association between cigarette smoking and HZ. Participants were collected from four rounds (2001, 2005, 2009 and 2013) of the Taiwan National Health Interview Survey. Incident cases of HZ were identified from the Taiwanese National Health Insurance database. Of the 57 641 participants, 3346 developed HZ during the observation period. After controlling for confounders, current smokers had a lower risk of incident HZ than never-smokers (adjusted hazard ratio 0.69; 95% CI 0.62-0.77). There was a trend toward a decreased risk of HZ with increasing numbers of cigarettes per day, years of smoking and cumulative pack-years of smoking among current smokers (Ptrend < 0.001). Former smoking was not associated with risk of HZ. In conclusion, current smoking was significantly associated with a decreased risk of developing HZ.

Cigarette smoking and risk of rosacea: a nationwide population-based cohort study.

BACKGROUND: Most evidence regarding the relationship between cigarette smoking and risk of rosacea is obtained from cross-sectional or case-control studies. OBJECTIVE: To examine the association between smoking and risk of developing rosacea. METHODS: Participants were collected from four rounds (2001, 2005, 2009 and 2013) of the Taiwan National Health Interview Survey. Incident cases of rosacea were identified from the National Health Insurance database. Cox proportional hazard model was used for the analyses. RESULTS: Of the 59 973 participants, 379 developed rosacea during a mean follow-up of 10.8 years. After adjustment for potential confounders, current smokers had a lower risk of rosacea than never smokers [adjusted hazard ratio (aHR) 0.60; 95% confidence interval (CI) 0.39-0.92]. An increase in smoking intensity was associated with a decreased risk of rosacea among current smokers (Ptrend  = 0.0101). Compared with never smokers, current smokers of >15 cigarettes/day had an aHR of 0.51 (95% CI: 0.26-0.99) for rosacea. For incident rosacea, the aHRs (95% CIs) of current smokers of ≤10 years of smoking and ≤10 pack-years of smoking were 0.44 (0.22-0.88) and 0.51 (0.29-0.89), respectively. Former smoking was not associated with rosacea risk. CONCLUSION: Current smoking was significantly associated with a decreased risk of rosacea.