Rotating Night Shift work and Colorectal Cancer Risk in the Nurses' Health Studies
A partir des données des deux cohortes "Nurses' Health Studies" incluant 190 810 infirmières, cette étude prospective évalue l'association entre un travail posté de nuit et le risque de cancer colorectal (période de suivi : 1988-2012 et 1989-2013 ; 1 965 cas)
Animal and human data have suggested that shift work involving circadian disruption may be carcinogenic for humans, but epidemiological evidence for colorectal cancer is still limited. We investigated the association of rotating night shift work and colorectal cancer risk in two prospective female cohorts, the Nurses' Health Study (NHS) and NHS2, with 24 years of follow up. In total, 190,810 women (NHS=77,439; NHS2=113,371) were included in this analysis, and 1,965 incident colorectal cancer cases (NHS=1,527; NHS2=438) were reported during follow up (NHS: 1988-2012, NHS2: 1989-2013). We used Cox proportional hazards models adjusted for a wide range of potential confounders. We did not observe an association between rotating night work duration and colorectal cancer risk in these cohorts (NHS: 1-14 years: Hazard Ratio (HR) 1.04, 95% CI 0.94, 1.16; 15+ years: HR 1.15, 95% CI 0.95, 1.39; Ptrend=0.14 and NHS2: 1-14 years: HR 0.81, 95% CI 0.66, 0.99; 15+ years: HR 0.96, 95% CI 0.56, 1.64 and Ptrend=0.88). In subsite analysis in NHS, rectal cancer risk increased after long-term (15+ years) rotating night shift work (proximal colon cancer: HR 1.00, 95%CI 0.75, 1.34, Ptrend= 0.90; distal colon cancer: HR 1.27, 95%CI 0.87, 1.85, Ptrend= 0.32; rectal cancer: HR 1.60, 95%CI 1.09, 2.34, Ptrend= 0.02). We found no overall evidence of an association between rotating night shift work and colorectal cancer risk in these two large cohorts of nurses. Risk for rectal cancer significantly increased with shift work duration, suggesting that long-term circadian disruption may play a role in rectal cancer development. This article is protected by copyright. All rights reserved.