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October/November 2011 (vol. 08/3)
Nurses’ breast cancer risk
A nested case–control study of nurses provides further evidence that nightshift work increases breast cancer risk. The study is based on 264 cases and 1,035 matched controls taken from a nationwide cohort of female nurses, aged between 32 and 70, in Denmark. Cancer diagnoses were obtained from the Danish Cancer Registry, while lifetime occupational and non-occupational exposure was assessed by structured telephone interview. Nurses who had worked shifts after midnight had a significant raised risk of breast cancer (odds ratio = 1.8; confidence interval 1.2–2.8). The highest raised risk (OR 2.9; 1.1–8.0) was for nurses who had worked periods of permanent nights as well as rotating shifts, although the confidence intervals overlapped with those who had worked rotating shifts but never permanent nights (OR 1.8; 1.2–2.8).
Occupational Health at Work October/November 2011 (vol. 08/3) pp40