Shift Work Adaptation Among Police Officers: The BCOPS Study

ABSTRACT

Few studies have examined shiftwork adaptation among police officers or potential differences in disease biomarkers among adapted and maladapted shiftworkers. This study characterized shiftwork adaptation among 430 police officers from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) study. Police officers working fixed night shifts with symptoms characteristic of adaptation and maladaptation were identified using latent class analysis (n = 242). Two approaches were applied, one with police-specific symptoms and another using more general symptoms as shiftwork adaptation indicators. Biomarkers of inflammation, heart rate variability, and cardiometabolic risk were then compared between shiftwork adaptation groups, and with officers working day shifts, after adjusting for confounding. When analyses included police-specific symptoms, maladapted shiftworkers (n = 73) had more self-reported stress, sleep disturbances, fatigue, and less social support than adapted shiftworkers (n = 169). Using more general symptoms, maladapted officers (n = 56) reported more stress and depression, and less social support than adapted officers (n = 186). In police-specific models, adjusted (least-squares) means (± standard error) of circulating interleukin-6 (IL-6) concentrations in maladapted officers (0.8 ± 0.1 ln[pg/ml]) were modestly elevated relative to adapted shiftworkers (0.7 ± 0.1 ln[pg/ml], p = .09) and relative to permanent day workers (0.5 ± 0.1 ln[pg/ml], p ≤ 0.01), and leptin levels in maladapted officers (9.6 ± 0.1 ln[pg/ml]) exceeded those in the adapted (9.4 ± 0.1 ln[pg/ml], p ≤ 0.01) and day shift groups (9.4 ± 0.1 ln[pg/ml], p = .03). In the general model, adjusted mean tumor necrosis factor-alpha (TNF-α) concentrations among maladapted officers (5.6 ± 0.23 pg/ml) exceeded the adapted (4.8 ± 0.2 pg/ml, p ≤ 0.01) and day workers (5.0 ± 0.2 pg/ml, p = .04), and insulin among maladapted officers was higher (2.4 ± 0.1 ln[uu/ml]) than the adapted group (1.8 ± 0.1 ln[uu/ml], p = .03). No differences were observed for the other biomarkers. The results suggest that maladaptation among police officers working fixed night shifts may lead to increases in leptin, insulin, IL-6, and TNF-α; however, the cross-sectional design and possible residual confounding preclude interpretation of cause and effect. Prospective studies are planned to further characterize the relationship between shiftwork maladaptation and biomarkers of chronic disease risk in this police officer cohort.

KEYWORDS:

• Police officers
• shiftwork adaptation and maladaptation
• metabolic and immune system biomarkers
• sleep
• stress

Acknowledgements

The work was performed at the University of South Carolina, Columbia, SC. The findings and conclusions expressed in this document are those of the author and do not reflect the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, U.S. Army Medical Center of Excellence, U.S. Army Training and Doctrine Command, U.S. Army Medicine, Department of the Army, Department of Defense, or the U.S. Government. JBB, MW, and JMV were supported by a grant from the National Institute of Justice (2019-R2-CX-0021).

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Author contributions

TN and JB devised the main conceptual ideas and design for the analysis. MA, PA, DF, and JV were responsible for the original study design, implementation, data collection, and database development. TN performed the analysis, and JB, MW, JG, AM assisted with the evaluation and interpretation of the results and supervised the work. TN and JB prepared the initial manuscript. MA, PA, DF, and JV provided critical feedback and conducted an internal scientific peer review of the manuscript. All authors discussed the results and concurred that the manuscript is suitable for submission for publication.

Disclaimer

The views and information presented are those of the authors and do not represent the official position of the U.S. Army Medical Center of Excellence, U.S. Army Training and Doctrine Command, Department of the Army, Department of Defense, or the U.S. Government.

Summary

This study utilized pre-specified symptoms and latent class analysis to identify police officers with or without symptoms that characterize shiftwork adaptation. To the author’s knowledge, this is the first study to report higher levels of cardiometabolic or inflammation biomarkers in maladapted relative to comparison shiftworkers; however, the cross-sectional study design precludes an interpretation of cause and effect.

Additional information

Funding

This work was supported by the National Institute of Justice [2019-R2-CX-0021].