The most commonly occurring cancer for women today is breast cancer. There have been studies that suggest that breast cancer in women is caused by abnormal sleep hours. This puts women who work at night at a higher risk of getting the disease. To date, though, Denmark is the only country that has awarded compensation for night shift women workers who have acquired the disease.
If other countries were to follow this trend, it can spell a sweeping economic difference all over the world. The latest study in China, however, didn’t reveal and direct connection between working at night and breast cancer.
Wong Ho-Chow who researches for the National Cancer Institute of Bethesda, Maryland, worked on this non-Western study. Chow confirmed that there was no association found even in women who worked at night for 25 years. The study was published in the American Journal of Epidemiology.
This study followed 70,000 working women in Shanghai and focused on their work shifts and cancer status. After ten years, 1% of these women developed breast cancer, but the women who worked at night didn’t reveal a heightened risk for cancer compared to women who worked during the daytime.
Earlier research on human beings and animals suggested that the light-dark cycle could put certain chemicals in the body out of balance. Therefore, those who worked at night and slept in the daytime could be facing a higher breast cancer risk.
Dr. Straif, an occupational medicine expert who was not involved in this study, said that the distinction could also be caused by the hormonal makeup of the participants. This was the first time that the study was conducted on Asians. In other words, there could be a hormonal disparity between Western women and Asians.
In 2007, Straif headed a study funded by WHO which concluded that working at night could indeed be a probable cause of cancer.