Association between shift work and risk of prostate cancer: a systematic review and meta-analysis of observational studies

Observational studies suggest that shift work may be associated with prostate cancer. However, the results are inconsistent. The objective of this study is to quantitatively assess the association between shift work and the risk of prostate cancer. Relevant studies were identified by a comprehensive search of the PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases to September 2017. We also reviewed the reference lists from retrieved articles. Observational studies that reported relative risk (RR) with 95% confidence intervals (CIs) for the association between shift work and the risk of prostate cancer were included. A linear and nonlinear dose-response meta-analysis was performed. Fifteen studies with 16 independent reports involving 2,546,822 individuals and 10,715 patients with prostate cancer were included. The pooled adjusted RR for the association between ever exposure to shift work and prostate cancer risk was 1.23 (95% CI, 1.08-1.41; P<0.001). A nonlinear association of prostate cancer risk with duration of shift work was identified (P for nonlinearity=0.001). Subgroup analysis demonstrated that a higher pooled RR of prostate cancer for studies among Asian populations (RR=1.98, 95% CI, 1.34-2.93; P=0.618). A positive association was observed in rotating shift groups (RR=1.10, 95% CI, 1.00-1.26; P=0.156), but not in other shift groups. Integrated evidence from this meta-analysis suggests that shift work is significantly associated with an increased risk of prostate cancer, and a nonlinear association between duration of shift work and prostate cancer was found.

Carcinogenesis. 2017 Nov 08 [Epub ahead of print]

Yong Gan, Liqing Li, Liangwen Zhang, Shijiao Yan, Chao Gao, Sai Hu, Yan Qiao, Sha Tang, Chao Wang, Zuxun Lu

Department of Social Medicine and Health Management, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China., Department of Management, School of Economics and Management, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi, China., Key Laboratory of Health Technology Assessment of Fujian Province University, School of Public Health, Xiamen University, Xiamen, Fujian, China., National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, China., School of Public Health, Changsha Medical University, Changsha, Hunan, China.