Cigarette Smoking, Alcohol Consumption, and Risk of Systemic Lupus Erythematosus: A Case-control Study in a Japanese Population

Objective. Cigarette smoking may be associated with increased risk of systemic lupus erythematosus (SLE), whereas the role of alcohol consumption is unknown. We examined the association between SLE risk and smoking or drinking. Methods. We investigated the relationship of smoking and drinking compared to SLE risk among 171 SLE cases and 492 healthy controls in female Japanese subjects. Unconditional logistic regression was used to compute OR and 95% Cl, with adjustments for several covariates. Results. Compared with nonsmoking, current smoking was significantly associated with increased risk of SLE (OR 3.06, 95% Cl 1.86-5.03). The higher the level of exposure to cigarette smoke, the higher the risk of SLE. Inhalation was also associated with increased SLE risk (OR 3.73, 95% Cl 1.46-9.94 for moderate inhalation; OR 3.06, 95% Cl 1.81-5.15 for deep inhalation). In contrast, light/moderate alcohol consumption had a protective effect on SLE risk (OR 0.38,95% CI 0.19-0.76). As for beer, the risks for non-beer drinkers and beer drinkers were similar. This also applies to alcoholic beverages other than beer. Conclusion. Our results suggest that smoking was positively associated with increased SLE risk whereas light/moderate alcohol consumption was inversely associated with SLE risk, irrespective of the type of alcoholic beverage. Additional studies are warranted to confirm these findings. (First Release May 15 2012; J Rheumatol 2012;39:1363-70; doi:10.3899/jrheum.111609)