The effect of sleep disorder on the work ability of workers in a car accessories manufacturing plant

Background: Work ability assessment and its affecting factors are important in the field of occupational health. One of the factors affecting work ability is sleep disorder, which is very common among workers. Therefore, the present study aimed to assess work ability and its relationship with sleep disorder in workers of a manufacturing plant. Methods: This cross- sectional study was conducted in a manufacturing plant in Tehran in 2013. All the 931 male workers of this plant were enrolled in the study, and their work ability was assessed using the Work Ability Index (WAI). The scores of this index range from 7 to 49, and the higher work ability score indicates a better work ability status. In this study, sleep disorder was assessed using the MUSIC-Norrtalje Questionnaire. Results: The average score of WAI was 42.81, ranging from 22 to 49. This score was significantly lower in the group with sleep disorder (41.28) than in the group without sleep disorder (44.10) (p< 0.001). The results of the logistic regression analysis revealed a significant relationship between work ability and sleep disorder even after adjustment for the confounding variables (OR= 2.52, 95% CI= 1.07 – 5.93, p= 0.033). Conclusion: The results of this study found a relationship between sleep disorder and work ability. Therefore, it is recommended to identify workers with sleep disorder and attend to their problem in order to increase their work ability.