A recent study published in the British Medical Journal found that women who worked night shift for 30 years or more were twice as likely to develop breast cancer than other women. The study found no increased risk for those who worked 14-29 years on night shift, but those with more years of night work had a significantly increased risk.
The study suggested that the increased risk of breast cancer was due to exposure to artificial light. Long-term exposure to artificial light may decrease the production of melatonin. Melatonin is a hormone that rises during the night and causes a person to feel tired, but when exposed to artificial light, night shift workers do not produce melatonin. A lack of melatonin can lead to an increase in estrogen levels in the body, which can trigger breast cancer in some women.
Further work is needed to better understand the link between long-term night shift work and breast cancer. The study authors say that, “As shift work is necessary for many occupations, understanding which specific shift patterns increase breast cancer risk, and how night shift work influences the pathway to breast cancer is needed for the development of healthy workplace policy.”
For the complete article on night shift work and breast cancer, click here.