RESUMEN
OBJECTIVES: This study was performed to investigate the effects of shift-work, in terms of general health concepts, insomnia, stress, quality of life and psychological health, at several manufacturing plants. METHODS: Questionnaires were distributed to 850 shift-workers (study group), and to 550 non-shift workers (as a control group). The questionnaires included questions on ; general health concepts, insomnia, stress, quality of life and psychological health. 455 shift-workers and 372 non-shift workers completed the questionnaires, and the factors influencing the health status and quality of life in workers estimated by multiple iogistic regression analysis. RESULTS: From the general health questionnaires, the mental health and health perception were significantly different between the shift and non-shift workers, with the better being former than the latter (p<0.05). Shift-workers complained of more insomnia when adjusted for age, working period, education and job satisfaction. Greater job satisfaction, was coupled with less complaints of insomnia (p<0.05). There were 200(43.96 %) shift workers classified as insomniac, whereas with the non-shift workers this figure was 84 (25.15 %), showing a significant difference between the two groups (p<0.05). Shift-workers were more stressed than the non-shift workers in their daily lives, which also showed significant difference (p<0.05). Less job satisfaction, was coupled with more complaints of stress (p<0.05). The quality of life of the shift-workers was lower than that of the nonshift workers (p<0.05). With the shift-workers complaining of more anxiety than the nonshift workers (p<0.05). CONCLUSIONS: Our results suggest that shift-workers suffer from physical and psychological distresses, sleep problems and stress than non-shift workers. Furthermore, it is presumed that these factors might negatively affect the quality of life of shift-workers. Accordingly, interventional methods for shift-worker's health and quality of life as a result of adverse effects of shift-work are needed.