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Updated: Nov 30, 2025

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Published on: August 8, 2019
Health Effects of Night and Irregular Shiftwork: A Longitudinal Cohort Study of US Workers
1Department of Urban and Environmental Policy and Planning, Tufts University, Medford, Massachusetts.
Objectives:
Evidence suggests that shiftwork results in adverse occupational health outcomes. This paper contributes to the literature by estimating the separate health effects of night and irregular shiftwork on a longitudinal panel of US workers.
Methods:
Data from a 20-year panel of worker surveys from the 1979 National Longitudinal Survey of Youth were used to predict self-reported health limitations related to night and irregular shiftwork using a series of random effects logit models.
Results:
Separate and combined specifications of shiftwork as night and irregular effort significantly increase the odds of health limitations compared with working a regular daytime schedule, with more pronounced effects for irregular work (odds ratio [OR] = 1.09 to 1.52) over night shift (OR = 1.03 to 1.14).
Conclusions:
The results suggest that both night and irregular shiftwork may have important negative implications on occupational health, with the deleterious effects particularly pronounced for irregularly scheduled work effort.
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