Rotating-shift workers may be at higher risk for prostate cancer

Rotating-shift workers appear to be at significant risk for prostate cancer compared with workers on a fixed-night shift, according to Japanese researchers.

Their prospective study, which is published in the American Journal of Epidemiology (2006; 164:549-55), included 14,052 working men in Japan who were surveyed between 1998 and 1990. Subjects were asked to indicate the most regular work schedule they had undertaken previously: day work, rotating-shift work, or fixed-night work.

During 111,974 person-years, 31 cases of prostate cancer were recorded. The Cox proportional hazards model was used to estimate the risk, with adjustments for age, family history of prostate cancer, body mass index, smoking, job type, and physical activity, among other factors. Compared with day workers, rotating-shift workers were significantly at risk for prostate cancer (relative risk, 3.0, 95% CI: 1.2, 7.7), whereas fixed-night work was associated with a small and nonsignificant increase in risk, according to the researchers from the University of Occupational and Environmental Health in Kitakyushu.