The perils of rotating shift work

Obesity has been on the rise in the USA and across the globe1 and is a major public health concern. In an article in this issue of the journal, Kubo et al (see page 327) show that rotating shift work, and in particular longer term (10+ years) rotating shift work, significantly increases the risk of weight gain and obesity.2 This is not the first study to report such an association, but is perhaps one of the most thorough and powerful examinations to date.

Recent developments on the international stage have shone a spotlight on the relationship between shift work and cancer as well as other chronic diseases. In response to mounting evidence in animal research and limited evidence in epidemiological studies, in 2007, the WHO's International Agency for Research on Cancer (IARC) classified shift work involving circadian disruption as probably carcinogenic in humans (group 2A).3 Denmark, after ruling in favour of breast cancer related disability insurance claims among rotating shift workers, has subsequently set a precedent for being the first nation to recognise shift work as an occupational health risk.4 Still, while cancer is one of the bleakest disease endpoints, a broader range of outcomes is seen: increases in cardiovascular risk, peptic ulcer disease, chronic fatigue and various sleep problems, a higher abortion and miscarriage rate as well as lower pregnancy rates, …