Occupational exposure to the sun and risk of skin and lip cancer among male wage earners in Denmark: a population-based case-control study

We examined the association between outdoor work and the risks of non-melanoma skin cancer, cutaneous malignant melanoma, and lip cancer in a population-based case-control study. Among all male wage earners in Denmark, 42,542 cases of non-melanoma skin cancer, 7,690 cases of cutaneous malignant melanoma, and 2,341 cases of lip cancer were identified in the nationwide Danish Cancer Registry. Population controls matched on sex and year of birth were selected at random among wage earners by incidence density sampling. Conditional logistic regression models were used to calculate odds ratios for risks of non-melanoma skin cancer, malignant melanoma, and lip cancer in relation to outdoor work after adjusting for covariates. For outdoor workers employed more than 10 years, the adjusted odds ratios were 0.83 (95% confidence interval (CI) 0.77-0.88) for non-melanoma skin cancer and 1.67 (95% CI 1.38-2.03) for lip cancer. Significantly reduced risk of basal cell cancers on the head, trunk, upper, or lower extremities were observed (range of odds ratios, 0.36 to 0.86). The results support the hypothesis of a decreased risk of non-melanoma skin cancer and an increased risk of lip cancer among outdoor workers in the Northern Hemisphere.