RT Journal Article
SR Electronic
T1 Association between shiftwork and the risk of colorectal cancer in females: a population-based case–control study
JF Occupational and Environmental Medicine
JO Occup Environ Med
FD BMJ Publishing Group Ltd
SP 344
OP 350
DO 10.1136/oemed-2017-104657
VO 75
IS 5
A1 Wa Mwenga Walasa
A1 Renee N Carey
A1 Si Si
A1 Lin Fritschi
A1 Jane S Heyworth
A1 Renae C Fernandez
A1 Terry Boyle
YR 2018
UL http://oem.bmj.com/content/75/5/344.abstract
AB Objective Research indicates that shiftwork may be associated with increased risks of adverse health outcomes, including some cancers. However, the evidence of an association between shiftwork and colorectal cancer risk is limited and inconclusive. Further, while several possible pathways through which shiftwork might result in cancer have been proposed, few studies have taken these factors into account. We investigated the association between two types of shiftwork (graveyard shiftwork and early-morning shiftwork) and six mechanistic shiftwork variables (including light at night and phase shift) and the risk of colorectal cancer among females in an Australian population-based case–control study. Graveyard shiftwork was the primary exposure of interest.Methods Participants (350 cases and 410 controls) completed a lifetime occupational history, and exposure to each of the eight shiftwork variables was assigned to participants through a job exposure matrix. We used logistic regression to calculate odds ratios (OR) and corresponding 95% confidence intervals (CI) for the association between different shiftwork variables and the risk of colorectal cancer, adjusting for potential demographic, lifestyle and medical confounders.Results Working in an occupation involving long-term exposure (>7.5 years) to graveyard shiftwork was not associated with colorectal cancer risk (adjusted OR 0.95, 95% CI 0.57 to 1.58). Similarly, no increased risks of colorectal cancer were seen for any of the other seven shiftwork variables examined.Conclusions No evidence of an increased risk of colorectal cancer among females who had worked in occupations involving shiftwork was observed in this study.