Sleep deprivation and obesity in shift workers in Southern Brazil

Abstract

Introduction The objective of our study was to explore the association between sleep deprivation and obesity among shift workers. Materials and methods A cross-sectional study was conducted on 905 shift workers among a poultry processing plant in southern Brazil. Obesity was defined as body mass index ⩾ 30 kg/m2. Time of sleep was categorized as: > 5 h continuous/day; =5 h continuous/day with some additional rest (sleep deprivation level I); and = 5 h/day without any additional rest (sleep deprivation level II). Socio-demographic, parental and behavioral variables were evaluated by means of a standardized pre-tested questionnaire. Potential confounding factors were controlling in the multivariable model. Results Obesity was more prevalent in the participants who were female, age 40 and older, had less schooling and reported excess weight in both parents. Sleep deprivation levels I and II were associated with increased income, number of meals consumed throughout the day and nightshift work. All of the workers who exhibited a degree of sleep deprivation worked the night shift. After controlling, the prevalence ratios of obesity were 1,32 (95% CI 0,84; 2,08) and 4,57 (95% CI: 2,51; 8,32) in the workers with sleep deprivation levels I and II, respectively, compared to the reference group. Conclusion These results show a strong association between sleep deprivation and obesity in shift workers, and that sleep deprivation may be a direct consequence of working at night. Acknowledgements This study was supported by the National Council of Technological and Scientific Development (CNPq; grants 477069/2009-6 and 478366/2011-6). R. Canuto received a scholarship from the Brazilian Federal Agency for Support and Evaluation of Graduated Education (CAPES). M.T.A. Olinto and M.P. Pattussi received research productivity grants from CNPq (grants 304793/2010-8 and 303424/2011-7).