Objective: With workforces in industrialized countries getting older, the study examined how shiftworking affects sleep in later life.
Method: Longitudinal data were collected in 1996, 2001, and 2006 from a large sample of employees who were 32, 42, 52, and 62 years old in 1996.
Results: Effects of shiftwork were most apparent in middle-aged participants, becoming less apparent in later years when people tended to leave shiftwork. Nevertheless, a group of younger former shiftworkers reported more sleep problems than those who had never worked shifts. Giving up shiftwork offset a trend for sleep problems to accumulate over time, with the net result of no change in sleep problems after cessation of shiftwork.
Conclusions: Poor sleep quality is a temporary consequence of shiftwork for some, whereas for others it is a cause of shiftwork intolerance.