Changes in the structure of health complaints as related to shiftwork exposure

Factor analyses of health complaints in groups with different length of shiftwork exposure show that the structure of these complaints changes with increasing shift experience, indicating the emergence of a shift-specific pattern of health complaints. After about 15 years of shiftwork, complaints related to disturbances of circadian-controlled functions can be found in the first factor whereas other complaints have their dominant loadings on a separate factor, representing general, non-shift-specific impairments. The results indicate that in this way shift-specific components of health impairment can be separated from other non-shift related components.