Shiftwork and decline in endothelial function among police officers

Background: Our objective was to assess the influence of shiftwork on change in endothelial function. Methods: This longitudinal study was conducted in 188 police officers (78.2% men). Shiftwork status (day, afternoon, night) was assessed objectively using daily Buffalo, NY payroll work history records. Brachial artery flow-mediated dilation (FMD) was assessed using ultrasound. Mean change in FMD% between 2004–2009 and 2010–2015 was compared across shiftwork using analysis of variance/covariance. Results: Overall, mean FMD% decreased from 5.74 ± 2.83 to 3.88 ± 2.11 over an average of 7 years among all officers; P < 0.0001. Effect modification by gender was significant. Among men (but not women), those who worked day shifts had a smaller mean (±SE) decrease in FMD% (−0.89 ± 0.35) compared with those who worked the afternoon (−2.69 ± 0.39; P = 0.001) or night shifts (−2.31 ± 0.45; P = 0.020) after risk factor adjustment. Conclusions: Larger declines in endothelial function were observed among men who worked afternoon or night shifts. Further investigation is warranted. Am. J. Ind. Med. 59:1001–1008, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.