Chronobiology internationalMar 7, 2012

Night shift work linked to overweight and belly fat in poultry plant workers in southern Brazil

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Mar 25, 2026

Abstract

Night-shift workers had a 42.2% prevalence of overweight compared to 34.3% among day-shift workers.

Night-shift workers exhibited a higher prevalence of abdominal obesity at 24.9% compared to 19.5% for day-shift workers.
The prevalence ratios for overweight and abdominal obesity among night-shift workers were 1.27 and 1.45, respectively, after adjusting for various factors.
Associations were observed between night shift work and increased risks of both overweight and abdominal obesity.
Sociodemographic factors, parental overweight status, behavioral habits, and sleep characteristics were considered in the analysis.

Simplified

The authors examined the associations of shiftwork with overweight and abdominal obesity through a cross-sectional study of 1206 employees 18 to 50 yrs of age who were working on a production line in a poultry processing plant. Night-shift workers (n = 800) were considered exposed, whereas day shiftworkers (n = 406) were considered nonexposed. Overweight was defined as a body mass index ≥ 25 kg/m(2) and abdominal obesity as a waist circumference ≥ 88 cm in women and ≥ 102 cm in men. The mean age of the workers was 30.5 yrs (standard deviation = 8.7 yrs), and 65.2% were women. Nightshift workers compared to dayshift workers showed higher prevalences of overweight (42.2% vs. 34.3%; p= .020) and abdominal obesity (24.9% vs. 19.5%; p = .037). After adjusting for sociodemographics, parental overweight status, behavioral characteristics, and sleep characteristics, including hours of sleep, the prevalence ratios for overweight and abdominal obesity were 1.27 (95% confidence interval [ CI]: 1.00-1.61) and 1.45 (95% CI: 1.10-1.92), respectively, for the nightshift workers compared to the dayshift workers. A consistent finding in our study was the independent contribution of night shiftwork to overweight and abdominal obesity among Brazilian workers. Further studies are needed to understand the biological mechanisms involved and the complex behavioral and social adaptations experienced by night-shift workers.

Full Text

Full text is available at the source.

View Full Text ↗

Night shift work linked to overweight and belly fat in poultry plant workers in southern Brazil

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief