By Janet Raloff
Two years ago, a pair of research teams each reported finding an elevated risk of breast cancer among women who sometimes worked nightshifts. One of the teams now finds that those women also face an increased risk of colorectal cancer.
Eva S. Schernhammer of Brigham and Women’s Hospital in Boston and her colleagues pored over data on 600 colorectal cancers diagnosed among 78,500 nurses participating in a long-running health study. As before, the researchers compared cancer incidence in women who reported working the graveyard shift with that of women who never worked nights.