Subjective health status of day and shift-working policemen.

To assess the subjective health status of day- and shift-working police officers, a questionnaire-based study was carried out. All the day-workers had previous shift experience. To control the age factor the total population of 2659 shift-working and 1303 day-working police officers was divided into four ten-year age classes. Factor analysis revealed that all the symptoms included in the questionnaire could be grouped into six factors. The prevalence rates of complaints showed that four of these factors (autonomous symptoms, musculo-skeletal symptoms, disturbance of appetite and indigestion, respiratory infections) were influenced by the main effects of age and shift work. Across all age classes the age-related changes in prevalence rates were strengthened by shift-work. In the other two factors (nervous symptoms, gastro-intestinal symptoms) an additional interaction effect could be observed. While the prevalence rates of the day-workers increased with age, those of the shift-workers decreased in the oldest age class. This drop of prevalence rates may be attributed to the influence of selection processes.