Tobacco smoking and hand eczema: a population-based study.

Background: Tobacco smoking has been proposed to promote hand eczema.

Objectives: To examine the association between tobacco smoking and hand eczema and to investigate a possible dose-response relation.

Methods: A national environmental health survey was performed in 2007. A questionnaire was mailed to 43,905 individuals and responses were obtained from 25,851 (59%). Questions on 1-year prevalence of hand eczema and on previous and current smoking were included. Respondents were asked to report number of cigarettes per day and to provide information on history of atopy and frequency of hand exposure to water.

Results: In total, answers regarding smoking and hand eczema were obtained from 25,428 individuals. Of regular daily smokers, 10·0% reported hand eczema vs. 9·1% of nonsmokers (P = 0·0951). A history of atopy showed the strongest influence on the occurrence of hand eczema: prevalence proportion ratio (PPR) 3·46. The PPR for hand eczema among individuals smoking > 15 cigarettes per day was 1·25 and 1·40 in uni- and multivariate analysis, respectively. Age, history of atopy, sex and water exposure were found to be confounders but not effect modifiers. A dose-response relation between level of smoking and 1-year prevalence of hand eczema was revealed with a PPR of 1·05 (P < 0·001) for the continuous variable of smoking habits, indicating a significantly increased prevalence of hand eczema among individuals with higher consumption of tobacco.

Conclusions: An association between heavy smoking and hand eczema was confirmed. It is important to consider the level of exposure, as a dose-response relation was revealed, and to be aware of confounding factors.