Occupational sunlight exposure and cancer incidence among Swedish construction workers

We studied sunlight exposure from outdoor work in relation to cancer, using data from 323,860 men participating in an occupational health service prog ram of the Swedish construction industry. An experienced industrial hygieni st assessed the exposure for 200 job tasks. We estimated relative risks (RR s) adjusted for age, smoking, and magnetic field exposure. There was an inc reased RR in the high-exposure group for myeloid leukemia [RR = 2.0, 95% co nfidence interval (95% CI) = 1.1-3.6] and lymphocytic leukemia (RR = 1.7, 9 5% CI = 0.9-3.2). For non-Hodgkin's lymphoma there was a 30% increase in ri sk in the high-exposure group (95% CI = 0.9-1.9). There was no increased ri sk of malignant melanoma, except for tumors of the head, face, and neck in the high-exposure group (RR = 2.0, 95% CI = 0.8-5.2), and we also found an increased risk for malignant melanoma of the eye in this group (RR = 3.4, 9 5% CI = 1.1-10.5). Outdoor workers had no increased risk of nonmelanoma ski n cancer. Nevertheless, the RR for lip cancer (squamous cell carcinoma) amo ng the high-exposure group was estimated at 1.8 (95% CI = 0.8-3.7). Among o ther sites, an increased risk of stomach cancer was suggested in this group (RR = 1.4, 95% CI = 1.0-1.9). The results for lymphoma, leukemia, and poss ibly also for stomach cancer might reflect a suppression of the immune syst em from ultraviolet light in outdoor workers.