In 2007, a working group of the International Agency for Research on Cancer classified shift work that involves circadian rhythm disruption as probably carcinogenic to humans. We carried out a review of the human epidemiological and mechanistic evidence, along with relevant health and safety policies and practice, to identify practical measures that should be undertaken to reduce the risk of cancer among shift workers.Methods
A literature search was carried out of the Proquest Dialogue databases, which includes MEDLINE, in order to identify the relevant scientific literature published from 2005–2015. In addition, we carried out an internet search for current health and safety policies and practices for managing shift workers.Results
There is evidence from the epidemiological studies that the increase in breast cancer risk amongst women who have worked night shifts is relatively modest and could be zero. Other risk factors for breast cancer associated with night work, such as poor diet, should be addressed by employers. Evidence for other cancers remains limited and inconsistent. If a mechanism exists, it is most likely to be night-time suppression of melatonin production. There has been limited evaluation of interventions to manage shift workers and research in this area is fragmented. Health and safety policies provide little on prevention.Conclusion
Health and safety practices for shift workers should address reduction of health risks by choosing shift rotations that minimise impact on circadian disruption, by employers facilitating female workers to attend breast cancer screening and by promoting and facilitating a healthy lifestyle.