Researchers from Brigham and Women's Hospital (BWH) have found that skin cancer, specifically melanoma, may be associated with a reduced risk in women who do shift work. The study was published in Journal of the National Cancer Institute.
The effect shift work has on health has been studied in the past and found to increase the risk of breast, prostate and colorectal cancer according to sciencedaily.com.
Lead study author, Eva Schernhammer M.D from BWH expressed that the risk of skin cancer among night-shift workers though had been unknown. Dr. Schernhammer has also studied the effects of shift work on other health issues such as ovarian cancer, menstrual cycles and signs of aging.
A known factor of shift work is that it disrupts the body’s circadian rhythm, specifically lowering melatonin levels. Melatonin has been found to have cancer protective properties. According to the University of Maryland, studies have shown that women with breast cancer and men with prostate cancer have lower than normal levels of melatonin.
What is interesting is that while low melatonin levels are thought to contribute to increased cancer risk in other parts of the body, this study showed that shift work, which lowers melatonin levels, might be associated with a decrease in skin cancer risk.
The researchers examined the relationship between rotating shifts and skin cancer by reviewing the records of 68,336 women in the Nurses’ Health Study over a period of 18 years. They found that woman who had worked a rotating nightshift for a longer period of time had a significantly lower association with skin cancer.
While the risk of all types of skin cancer was reduced, the strongest was observed for melanoma. “Working ten or more years of rotating night-shifts was associated with 44 percent decreased risk of melanoma”. (1)
The researchers also found that darker-haired women had the lowest skin cancer risk. This suggests that there may also be a genetic component that affects melatonin suppression.
Melatonin is a hormone released by the pineal gland in the body.