BWH Logo Shift work may be considered as a health hazard, but is also beneficial for humans. A recent study commenced by the Brigham and Women’s Hospital (BWH) suggests that shift work decreases risk of skin cancer in women. It is believed that shift work induces desynchrony of the circadian system, thereby hampering melatonin production.

The 18 year old study followed 10,799 incidents of skin cancer among 68,336 women in the Nurses’ Health Study. Scientists kept a track on rotating night shifts and incidences of skin cancer. A direct connection between higher duration of working rotating nightshifts and skin cancer then appeared. Working ten or more years of rotating night-shifts was possibly linked with 44 percent declined threat of melanoma.

“Shift work has been associated with increased risk of certain cancers and chronic non-malignant diseases such as gastrointestinal disorders, cardiovascular disease, and diabetes,” said lead study author Eva Schernhammer, MD, DrPh, a researcher in the Channing Laboratory at BWH. “However, while shift work has been associated with other cancers, the risk of skin cancer among night-shift workers is unknown.”

It was noted that darker-haired women supposedly had the lowest risk of skin cancer. No differences in risk by sunlight exposure level at baseline, geographic residence or body location of skin cancer were registered. It seems that women with dark hair have a genetic component that affects the extent of melatonin suppression during night work and skin cancer risk. In spite of the benefits in having stable circadian rhythms, shift workers may suffer from various diseases.

The study is published online in the Journal of the National Cancer Institute.