The relationship between current and former shift work and the metabolic syndrome.
OBJECTIVE
The occurrence of possible health hazards among former shift workers is not well-known. We studied         associations of former and current shift work with the metabolic syndrome (MetS).


METHODS
Participants were 1811         full-time employees of a large airline company (1009 men). Working times were categorized into five groups: day worker         [N=297 (the reference group)], former shift worker (N=341), 2-shift worker (N=418), night-shift worker (N=283), and         in-flight worker (N=472). MetS was measured by the International Diabetes Federation (IDF) criteria and the National         Institute of Health Adult Treatment Panel III (NCEP) guideline. The prevalence of the syndrome in the study population         was 28.5% and 20.8%, respectively.


RESULTS
Among male former shift workers, MetS was more prevalent compared to male         day workers [IDF: age-adjusted odds ratio (OR) 2.13, 95% confidence interval (95% CI) 1.35-3.37; NCEP: OR 1.83,         95% CI 1.13-2.96]. Associations did not change after additional adjustments for education, smoking, physical         activity, alcohol consumption, and insomnia symptoms (IDF: OR 2.00, 95% CI 1.26-3.19; NCEP: 1.67, 95% CI         1.02-2.72). Male 2-shift workers also had an elevated risk of IDF-defined MetS (OR 1.64, 95% CI 1.06-2.55)         but the association weakened in the fully adjusted analyses (OR 1.48, 95% CI 0.93-2.24). Prevalence of the MetS         was marginally significantly higher among night-shift work (IDF: OR 1.51, 95% CI 0.95-2.34) and was attenuated         further with additional adjustments (OR 1.37, 95% CI 0.84-2.22). Among women, no significant differences in         prevalence of the MetS between day work and shift work were observed.


CONCLUSIONS
Findings of the cross-sectional study         suggest that MetS diagnosed by standardized criteria is more prevalent among former male shift workers than current day         workers who have never worked in shifts.
Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, FIN-00250, Helsinki, Finland. Sampsa.Puttonen@ttl.fi
Sampsa
S
Puttonen
Katriina
K
Viitasalo
Mikko
M
Härmä
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000503:physiopathology*; D008875:Middle Aged; D014940:Work Schedule Tolerance