Shift work and risk of skin cancer: A systematic review and meta-analysis

Abstract

Shift work with circadian disruption has been considered as a carcinogenic risk factor for skin cancer. The few prior studies that investigated the association between shift work and skin cancer have inconclusive results. Our main objective was to evaluate the associations between shift work and the risks of different types of skin cancer. We systematically searched PubMed, Web of Science, Cochrane Library, EMBASE and Science Direct until October 2018 for studies that included a relationship between shift work and skin cancer. Our search yielded 193 articles and 9 studies met the criteria for our review. The included studies involved 3,579,147 participants and 17,308 skin cancer cases. Overall, ever shift work, was associated with increased risk of melanoma (RR = 1.10, 95% CI = 1.05-1.16) and a significant decrease in the risk of BCC (RR = 0.90, 95% CI = 0.88-0.93). No association between shift work and the risk of SCC was detected. Interestingly, our dose response analysis demonstrated that the risk of melanoma cumulatively increases by 2% for every year of shift work (RR = 1.02; 95% CI = 1.00-1.03). In conclusion, shift work is associated with increased risk of melanoma and deceased risk of BCC. Further studies are needed to confirm our findings and to elucidate the related potential biological mechanisms.

Figure 1

Flow chart for the process of eligible articles selection.

Figure 2

Forest plots depicting the risk estimates from included studies on the associations between shift work and risks of different types of skin cancer (a) Melanoma, (b) BCC, (c) SCC, RR: relative risk, CI: confidence interval. I² is an indicator that used to determine the degree of heterogeneity in the meta-analysis. The horizontal lines and squares correspond to the 95% CI and to the study-specific RR. The area of the square represents the weight of each study. The dotted red-line and the diamond represents the 95% CI and the pooled RR.