Supplementary Material for: Cigarette Smoking and the Risk of Cutaneous Melanoma: A Case-Control Study

Objective: Previous studies regarding cigarette smoking causing a lower risk of melanoma are inconclusive. Here, we re-examined melanoma risk in relation to cigarette smoking in a large, case-control study. Methods: In total 1,157 patients with melanoma diagnosed between 2003 and 2011 in the Netherlands and 5,595 controls from the Nijmegen Biomedical Study were included. Information concerning smoking habits and known risk factors for melanoma were obtained through self-administered questionnaires. Logistic regression analyses stratified by gender were performed to study the risk of cigarette smoking on melanoma risk, adjusted for age, marital status, highest level of education, skin type, sun vacation, use of solarium, time spent outdoors, and sun protective measures. Results: Among men, current and former smokers did not have a higher risk of melanoma compared to never smokers: adjusted odds ratio (OR) = 0.56 (95% confidence interval [CI]: 0.40–0.79) and adjusted OR = 0.50 (95% CI: 0.39–0.64), respectively. With an increasing number of years smoked the risk of melanoma decreased: 40 years: OR = 0.26 (95% CI: 0.15–0.44). No clear trend was found for the number of cigarettes smoked. Results for females were less clear and not statistically significant (current smoker: adjusted OR = 0.96, 95% CI: 0.74–1.26, former smoker: adjusted OR = 0.89, 95% CI: 0.73–1.08). Conclusion: This study shows a strong inverse association between cigarette smoking and melanoma risk in men. Fundamental laboratory research is necessary to investigate the biological relation between smoking cigarettes and melanoma.