24-hour work shifts, sedentary work, and obesity in male firefighters

Source: BongKyoo Choi, Marnie Dobson, Peter Schnall, and Javier Garcia-Rivas, American Journal of Industrial Medicine, Volume 59 Issue 6, June 2016
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From the abstract:
Background: Little is known about the occupational risk factors for obesity in US firefighters.
Methods: 308 male California firefighters, who participated in a work and obesity project, were chosen. Working conditions were measured with a firefighter-specific occupational health questionnaire. Adiposity was clinically assessed using body mass index (BMI), waist circumference (WC), and body fat percent.
Results: In a multivariate analysis, the prevalence of obesity by all measures was significantly higher in the firefighters who reported seventeen to twenty-one shifts than those who reported eight to eleven shifts in the past month. Prolonged sedentary work was also a risk factor for obesity by BMI. Furthermore, there was a linear dose-response relationship of obesity by BMI and WC with the number of 24-hr shifts and sedentary work.
Conclusions: Many additional 24-hr shifts and prolonged sedentary work substantially increased the risk for obesity in male firefighters.