Shift work is significantly and positively associated with dementia: A meta-analysis study

Kuo-Wei Lee; Chen-Cheng Yang; Chun-Hung Chen; Chih-Hsing Hung; Hung-Yi Chuang

doi:10.3389/fpubh.2023.998464

Shift work is significantly and positively associated with dementia: A meta-analysis study

Front Public Health. 2023 Feb 16:11:998464. doi: 10.3389/fpubh.2023.998464. eCollection 2023.

Authors

Kuo-Wei Lee^{1

2

3}, Chen-Cheng Yang^{3

4

5

6}, Chun-Hung Chen^{1

2}, Chih-Hsing Hung⁷, Hung-Yi Chuang^{4

6

8}

Affiliations

¹ Department of Neurology, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
² Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
³ College of Medicine, Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁴ Department of Occupational and Environmental Medicine, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁵ Department of Occupational and Environmental Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁶ Research Center for Precision Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁷ Environmental and Occupational Medicine Center, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁸ Department of Public Health and Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.

Abstract

Background: Shift work may disrupt the sleep and wake cycles and negatively affect physical and mental health. Dementia is a neurodegenerative disorder with progressively declining cognition that is receiving increasing attention. Studies on the association between shift work and dementia are rare. Herein, we conducted a meta-analysis to investigate the association between shift work and dementia.

Materials and methods: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched the PubMed, Embase, and Web of Science databases using a related set of keywords. The inclusion criteria were as follows: (1) adult employees working in a factory, company, or organization; (2) exposure to shift work/non-shift work; and (3) outcome of dementia based on examination or assessment. A meta-analysis using a fixed-effects model was performed. The hazard ratio of dementia was compared between shift workers and non-shift workers.

Results: Five studies were included in the quantitative synthesis, and two were selected for further meta-analysis. A random-effects model showed a modest association between shift work and an increase in dementia cases (pooled hazard ratio = 1.13; 95% confidence interval: 1.04-1.23; p = 0.04). This association also occurred in night workers for more than 1 year.

Conclusion: Shift work and long-term night work were modestly associated with a higher risk of developing dementia. Avoiding long-term night shifts may be effective in reducing dementia risk. Further studies are required to confirm this hypothesis.

Keywords: Alzheimer disease; dementia; meta-analysis; night shift; occupational medicine; shift work.

Publication types

Meta-Analysis
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cognition*
Databases, Factual
Dementia*
Humans
Mental Health
Sleep

Grants and funding

This work was partially supported by the Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, from the Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan, Kaohsiung Medical University Research Center Grant (KMU-TC111A01 and KMUTC111IFSP01), and Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University (S-110-09).