Ultraviolet radiation exposure and melanoma risk among over 2 million Ontario workers.

This study aimed to examine the association between occupational sun exposure and melanoma risk among a large cohort of 2.4 million workers. These workers were identified through accepted compensation claims, which were linked to cancer records to identify melanoma diagnoses from 1983 to 2019 in Ontario, Canada. An existing job exposure matrix, SUNJEM, was used to estimate occupational solar ultraviolet radiation (UVR) exposure as low-intermittent (intermittent/partly shaded exposure), moderate (2 to < 6 h/day), or high (≥6 h/day). The association between occupational solar UVR and melanoma risk was assessed using Cox proportional hazard regression models, with age as the timescale and adjustment for sex and birth cohort. A total of 8,170 incident melanoma cases were identified among workers. Both the low-intermittent (HR = 1.26; 95%CI = 1.17–1.38) and high exposure groups (HR = 1.13; 95%CI = 1.01–1.26) had higher rates of melanoma than indoor workers. The low-intermittent exposure group had elevated melanoma rates on the arms and trunk (body), while the high exposure group had an elevated rate on the head and trunk. High risk occupation groups included truck drivers and farmers. Findings support an association between low-intermittent and high occupational solar UVR exposures and melanoma risk. Sun protection measures should focus on at-risk occupational groups.