Disabling low back pain associated with night shift duration: sleep problems as a potentiator.

BACKGROUND We investigated how night shift duration and sleep problems were jointly associated with disabling low back pain (LBP) among workers in different occupations. METHODS An online-survey was conducted regarding work schedules, disabling LBP, sleep problems, and other relevant factors in 5,008 workers who were randomly selected from a market research panel. Multiple logistic regression analyses determined the joint associations of night shift duration (0 [permanent day shift], <8, 8-9.9, 10-15.9, ≥16 hr) and sleep problems (no, yes) with disabling LBP adjusted for potential confounders. RESULTS A night shift ≥16 hr was associated with a significant increase in the likelihood of disabling LBP. The magnitude of this association was elevated when participants perceived sleep problems including both sleep duration and quality. CONCLUSION Associations between extended night shifts and disabling LBP became stronger in the presence of short or poor quality sleep.