A study has led a Chinese oncologist to establish a link between night work and 11 cases of cancer among women from North America and Europe. The latter would be 19% more likely to develop cancer than women working the day.
In a recent study published in Cancer Epidemiology, Biomarkers & Prevention, Xuelei Ma, an oncologist at the Laboratory of the Center for Biotherapy and Oncology at Sichuan University, China, classifies night work as a risk factor for many cancers in women working at night. Comparing data from 61 previous studies including 114,628 cancer cases, 3,909,152 participants from North America, Europe, Australia, and Asia, the scientist made the link between 11 types of cancer and long-term night work.
According to him, working at night would increase the risk of cancer in women by 19%: + 41% for skin cancer, + 32% for breast cancer and + 18% for digestive cancer. More seriously, the risk of breast cancer would increase by 3.3% every five years in the case of long-term night work. Strangely enough, however, this would only affect women from North America and Europe. "We were surprised to see the association between night work and the risk of breast cancer, only among women in North America and Europe," said Xuelei Ma. "It is possible that these women have higher levels of sex hormones, which have been positively associated with hormonal cancers such as breast cancer. "
Nurses are the most exposed
Of all the professions analyzed, the risk would appear to be higher for nurses. Those who work at night have a 58% risk of developing breast cancer, 35% have digestive cancer (stomach, rectal colon, liver, esophagus, pancreas) and a 28% chance of having lung cancer. "Night nurses are probably more likely to be screened," the researcher says to justify this difference. "Our study indicates that night work is a risk factor for common cancers among women." And to conclude: "These results could lead to effective measures to protect women workers at night in the long term, and they should have regular physical exams and cancer screenings."