Study objectives: To investigate the effects of occupational factors on both the incidence and the disappearance of sleep disorders after a five-year follow-up period.
Design: A prospective longitudinal investigation E.S.T.E.V. carried out in 1990 and 1995.
Setting: Seven regions of France.
Subjects: A random sample of employed men and women born in 1938, 1943, 1948, and 1953. In 1990, 21,378 subjects were interviewed (87% of those contacted), and 88% were interviewed again in 1995.
Measures: Sleep disorders (SD), objectifiable and psychosocial working conditions.
Results: Prevalence of SD increased with age and were more frequent among women than men in every age group. Incidence of SD varied little with age, but their disappearance decreased with age. After adjustment for age and sex, SD in 1995 were found to be associated both with objectifiable working conditions and with psychosocial aspects of the way work is experienced. Among objectifiable occupational risk factors, shift work, work week often longer than 48 hours, and exposure to vibrations appeared to be the principal risk factors for SD. Among psychosocial occupational factors, finding it difficult or irksome to have to hurry appeared to be the principal risk factor.
Conclusions: Taking into account the adjustments for health criteria, sociodemographic characteristics, and leisure activities, these results suggest useful courses of action for prevention which, it seems to us, must not be only limited to objectifiable working conditions. Issues about work organization, while clearly difficult to resolve, must also be taken into account.