A meta-analysis confirms a positive association between long-term night shift work and an increased overall risk for cancer in women, particularly breast cancer.In North America and Europe, working the night shift was associated with a 32% increased risk for breast cancer.Night nurses were found to have a "remarkable" 58% increased risk.For every 5 years a woman spent working nights, breast cancer risk increased by 3.3%.The review, published online January 8 in Cancer Epidemiology, Biomarkers & Prevention, was led by Xuelei Ma, PhD, from the West China Medical Center of Sichuan University, Chengdu.Long-term night shift workers should have regular physical examinations and cancer screenings.