Objective To perform a systematic review and meta-analysis to collate evidence of the effects of smoking on the risk of nonmelanoma skin cancer.
Data Sources We searched 4 electronic databases (from inception to October 2010) and scanned the reference lists of the publications retrieved to identify eligible comparative epidemiologic studies.
Study Selection Titles, abstracts, and full text were assessed independently by 2 authors against prespecified inclusion/exclusion criteria.
Data Extraction Data were extracted and quality was assessed independently by 2 authors using the Newcastle-Ottawa Scale.
Data Synthesis Meta-analysis was performed using random-effects models. Results are presented as odds ratios (ORs) with 95% CIs. Heterogeneity was assessed using I2. Twenty-five studies were included. Smoking was significantly associated with cutaneous squamous cell carcinoma (OR, 1.52; 95% CI, 1.15-2.01; I2 = 64%; 6 studies). Smoking was not significantly associated with basal cell carcinoma (OR, 0.95; 95% CI, 0.82-1.09; I2 = 59%; 14 studies) or nonmelanoma skin cancer (OR, 0.62; 95% CI, 0.21-1.79; I2 = 34%; 2 studies).
Conclusion This study clearly demonstrates that smoking increases the risk of cutaneous squamous cell carcinoma; however, smoking does not appear to modify the risk of basal cell carcinoma.