Sweeney MR, et al. - Using Cox proportional hazards models, researchers examined the link between baseline work schedule characteristics and incident breast cancer among participants (n = 48,451) in the prospective Sister Study cohort. They gathered current and past occupational history for the participants. A follow-up of a mean duration of 9.1 years was performed, during which, 3,191 incident cases were diagnosed. They found little to no rise in risk related to work schedule characteristics. Although increased breast cancer risk was observed in relation to short-term night work and rotating shift work at night, working nights for more than 5 years was not related to risk. In support of the notion that a higher risk of breast cancer is associated with rotating shift work or work at night, little evidence was gained by experts. A possible exception to this could be individuals who engaged in such work for short durations of time.