Investigating the impact of shift work on depression: Insights from sleep duration and physical activity.

Abstract

Background: Shift work has been associated to a higher risk of depression and other health problems.

Objective: This study aims to explore the connection between shift work and depression using NHANES data, with a focus on the roles of sleep duration and physical activity.

Methods: NHANES data from 2007 to 2025 were examined using weighted multivariable logistic regression and stratified analysis, adjusting for demographic, chronic disease, and lifestyle factors. The impact of sleep duration and physical activity on depression among shift workers was examined using generalized additive models.

Results: The study included 4965 participants. Adjusting for all covariates, shift work was significantly linked to increased depression risk (OR = 1.25, 95% CI: 1.05-1.48, p = 0.0127). For shift workers, each additional hour of sleep reduced depression risk by 19% (OR = 0.81, 95% CI: 0.72-0.91, p = 0.0007), and those with adequate sleep had a 40% lower depression risk compared to those with insufficient sleep (OR = 0.60, 95% CI: 0.42-0.87, p = 0.0072). Regular physical activity reduced depression risk by 44% (OR = 0.56, 95% CI: 0.36-0.87, p = 0.0104), whereas insufficient activity showed no significant impact (OR = 0.83, 95% CI: 0.50-1.38, p = 0.4731).

Conclusions: Shift work increases depression risk, while sufficient sleep and physical activity are protective. These findings underscore the importance of improving conditions for shift workers and developing preventive strategies.