The association between different night shiftwork factors and breast cancer: a case-control study

Lin Fritschi, Thomas Erren, Deborah Catherine Glass, Jennifer Girschik, Allyson Thomson, Christobel Saunders, Terry J Boyle, Sonia El-Zaemey, Pierra A Rogers, Susan Peters, Terry J Slevin, A D'Orsogna, Frank De Vocht, Roel Vermeulen, Jane Heyworth

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70 Citations (Scopus)

Abstract

Research on the possible association between shiftwork and breast cancer is complicated because there are many different shiftwork factors, which might be involved including: light at night, phase shift, sleep disruption and changes in lifestyle factors while on shiftwork (diet, physical activity, alcohol intake and low sun exposure). Methods:We conducted a population-based case-control study in Western Australia from 2009 to 2011 with 1205 incident breast cancer cases and 1789 frequency age-matched controls. A self-administered questionnaire was used to collect demographic, reproductive, and lifestyle factors and lifetime occupational history and a telephone interview was used to obtain further details about the shiftwork factors listed above. Results:A small increase in risk was suggested for those ever doing the graveyard shift (work between midnight and 0500 hours) and breast cancer (odds ratio (OR)=1.16, 95 confidence interval (CI)=0.97-1.39). For phase shift, we found a 22 increase in breast cancer risk (OR=1.22, 95 CI=1.01-1.47) with a statistically significant dose-response relationship (P=0.04). For the other shiftwork factors, risks were marginally elevated and not statistically significant. Conclusion:We found some evidence that some of the factors involved in shiftwork may be associated with breast cancer but the ORs were low and there were inconsistencies in duration and dose-response relationships
Original languageEnglish
Pages (from-to)2472 - 2480
Number of pages9
JournalBritish Journal of Cancer
Volume109
Issue number9
DOIs
Publication statusPublished - 2013

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