Night shift work, MTNR1B rs10830963 polymorphism and prostate cancer risk: Findings from a prospective, population-based study.

BACKGROUND: The association between night shift work and prostate cancer is controversial. Evidence shows that genetic and environmental factors both contribute to the development of prostate cancer. It is well-known that melatonin plays a protective role in prostate cancer. MTNR1B rs10830963 influences the dynamics of melatonin secretion, and night shift work, which disrupts our internal circadian rhythms, also dysregulates the production of melatonin. Therefore, we aimed to examine the interaction between night shift work and rs10830963 polymorphism on prostate cancer.

METHODS: This is a prospective cohort study based on UK Biobank which included 133416 employed male participants. Exposures included night shift work and rs10830963 polymorphism. The primary outcome was the incidence of prostate cancer. Cox regression analysis was used to estimate the association of night shift work and MTNR1B rs10830963 with prostate cancer.

RESULTS: A significant interaction was found between night shift work and MTNR1B rs10830963 on the incidence of prostate cancer (P = 0.009). Among non-night shift workers, rs10830963 polymorphism was not significantly associated with the risk of prostate cancer. Among night shift workers, compared to CC carriers, GC carriers had a significantly lower risk of prostate cancer (HR:0.68, 95%CI:0.51-0.92), and similar associations were more evident for GG carriers (HR:0.33, 95%CI:0.15-0.75).

CONCLUSIONS: Compared with MTNR1B rs10830963 CC, carrying allele G may reduce the risk of prostate cancer when exposed to night shift work.

IMPACT: These results suggest that rs10830963 G carriers may have a lower risk of prostate cancer when taking night shifts.