Skin cancer risk in outdoor workers: a European multicenter case-control study

A systematic revision of the literature was conducted in order to undertake a comprehensive meta-analysis of all published observational studies on melanoma. An extensive analysis of the inconsistencies and variability in the estimates was performed to provide some clues about its Epidemiology. Following a systematic literature search, relative risks (RRs) for sun exposure were extracted from 57 studies published before September 2002. Intermittent sun exposure and sunburn history were shown to play considerable roles as risk factors for melanoma, whereas a high occupational sun exposure seemed to be inversely associated to melanoma. The country of study and adjustment of the estimates adjuste for phenotype and photo-type were significantly associated with the variability of the intermittent sun exposure estimates (P = 0.024, 0.003 and 0.030, respectively). For chronic sun exposure, inclusion of controls with dermatological diseases and latitude resulted in significantly different data (P = 0.05 and 0.031, respectively). Latitude was also shown to be important (P = 0.031) for a history of sunburn; studies conducted at higher latitudes presented higher risks for a history of sunburns. Role of country, inclusion of controls with dermatological diseases and other study features seemed to suggest that "well conducted" studies supported the intermittent sun exposure hypothesis: a positive association for intermittent sun exposure and an inverse association with a high continuous pattern of sun exposure.

Despite the fact that ultraviolet (UV) light exposure is the most important risk factor for cutaneous squamous cell carcinoma (SCC) there is an ongoing debate concerning the relationship between cumulative work-related UV exposure and SCC occurrence. To analyse comprehensively the relationship between work-related UV exposure and SCC risk. We conducted a systematic electronic literature search in PubMed (up to 5 May 2010) supplemented by a hand search, which identified 18 relevant studies that were included in the review. Data abstraction and study quality assessment was done independently by two reviewers. Maximally adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs) of all included studies were pooled in a random-effects meta-analysis. Sensitivity analysis included meta-regression on study-specific covariates to explore the robustness of the results and to identify sources of heterogeneity between studies. Eighteen studies (six cohort studies, 12 case-control studies) met the eligibility criteria and were included in the systematic review. Sixteen studies (89%) found an increased risk of SCC in individuals with occupational UV light exposure compared with individuals without occupational UV light exposure, reaching statistical significance in 12 studies. Two studies found no association between occupational UV light exposure and SCC occurrence. The pooled OR (95% CI) was 1·77 (1·40-2·22) and did not differ significantly between cohort studies [OR (95% CI): 1·68 (1·08-2·63)] and case-control studies [OR (95% CI): 1·77 (1·37-2·30)]. Meta-regression analyses suggested an increasing strength of the association between occupational UV light exposure and SCC risk with decreasing latitude. In summary, there is consistent epidemiological evidence for a positive association between occupational UV light exposure and SCC risk. © 2011 The Authors. BJD © 2011 British Association of Dermatologists.