Sweeney MR, et al. - Researchers estimated the link between baseline work schedule characteristics and incident breast cancer among participants in the prospective Sister Study cohort, using Cox proportional hazards models, given inconsistent outcomes have been reported in many studies evaluating night shift work in relation to breast cancer risk. Current and prior occupational history was gathered for 48,451 participants. A total of 3,191 incident cases were diagnosed during follow-up (mean = 9.1 years). They found little to no rise in risk related to work schedule characteristics. They observed increased breast cancer risk in relation to short-term night work or rotating shift work at night, there was no link between working nights for more than 5 years and risk of breast cancer. Overall, little evidence demonstrating a link between rotating shift work or work at night and a higher risk of breast cancer was found, except probably among those who participated in such work for short durations of time.