The Association Between the Number of Consecutive Night Shifts and Insomnia Among Shift Workers: A Multi-Center Study

Juho Sim, Byung Yoon Yun, Jiho Lee, Sung Kyung Kim, Seunghyun Lee, Ara Cho, Seunghan Kim, Chang Young Kim, Yeon Suh Oh, Jin Ha Yoon

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Objectives: There is a need to determine the optimal limit of consecutive night shift work to reduce insomnia caused by the accumulation of sleep problems among night shift workers. This study aimed to investigate the prevalence of insomnia caused by consecutive night shifts and evaluate the night shift duration that worsens insomnia the most, using a large amount of medical examination data. Methods: Night shift profiles and baseline demographics data of three hospitals were collected from January 2015 to December 2017. For subjects who had been examined more than once at the same institution, information corresponding to the most recent date was used. Multivariate logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Pooled ORs were calculated by using the results of the three institutions. Results: Of the 33,669 participants, 31.3% were female. The average age was 41.1 ± 11.1 years and the prevalence of insomnia was 38.7% (n = 13,025). After adjusting for potential confounders and compared to workers who reported not working in consecutive night shifts, odds of insomnia were greatest among workers reporting working three consecutive nights (OR 2.65, 95% CI 1.97–3.56) followed by those working two nights (OR 1.81, 95% CI 1.45–2.26), five nights (OR 1.78, 95% CI 1.56–2.03), and four nights (OR 1.68, 95% CI 1.55–1.82). Conclusion: Our study demonstrates a significant relationship between consecutive night shift and insomnia with multicenter examination data, using common data model. This study could be a basis for establishing policies and guidelines that improve night shift workers' health.

Original languageEnglish
Article number761279
JournalFrontiers in Public Health
Publication statusPublished - 2021 Nov 17

Bibliographical note

Funding Information:
This work was supported by the Republic of Korea Health Industry Development Institute through Social and Environmental Risk Research funded by the Ministry of Health & Welfare (HI19C0052).

Publisher Copyright:
Copyright © 2021 Sim, Yun, Lee, Kim, Lee, Cho, Kim, Kim, Oh and Yoon.

All Science Journal Classification (ASJC) codes

  • Public Health, Environmental and Occupational Health


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