Night Shift Workers At Greater Risk For Cancer

Heart disease, obesity, sleep disorders are not just the only health problems which concern night shift workers. In a recent news report, researchers in China have found that women who work the night shift have a 19% increased risk of developing cancer compared to women who do not work at night.

According to researchers, women who work at night have 41% higher risk of skin cancer, 32% higher risk of breast cancer and 18% greater risk of digestive system cancers compared to women who did not work night shifts.

According to Xuelei Ma, senior author of the paper and assistant professor at Sichuan University, she said that the longer the women worked night shifts, the higher their risk. For every five years of night shift work, the risk of breast cancer for example, went up by 3.3%.



“Night shift is a current social phenomenon that is gaining and rising in popularity and can have adverse effects on health,” Ma wrote in an email to TIME discussing the study’s results. “It is warranted that long term night shifters take advantage of tumor screening and that protection measures for personnel should also be considered.

There might be several other factors that contribute to the higher risk of cancer for night shifters but according to previous studies in animals and people, disruptions to hormone levels might be one reason. Levels of melatonin, for example, which generally rise at night in response to darkness, are suppressed when people remain awake under artificial light. This may become a factor in the growth of tumor since melatonin is an antioxidant that stops cancer cells and also suppresses blood vessel growth associated with tumors. Genes that are responsible for repairing DNA can also get affected due to the disturbance in the normal sleep-wake cycle. This could lead to more abnormally growing cells that become cancerous.