The relationship between night work, chronotype, and cardiometabolic risk factors in female hospital employees

ABSTRACT

Night work has emerged as a risk factor for many chronic diseases, including obesity, diabetes, and cardiovascular disease. While night work is linked to a number of cardiometabolic indices, few studies have explored how different parameters, such as cumulative night work and intensity of night work, may influence cardiometabolic risk. Fewer studies have also explored the relationship while considering chronotype, a potential modifier between shift-induced circadian disruption and cardiometabolic outcomes. The main objective is to determine the association between night work parameters and cardiometabolic risk factors. The secondary objective is to assess how the association between night work parameters and cardiometabolic risk factors differs by chronotype. A cross-sectional study was conducted with 325 full- and part-time female hospital employees (168 rotating night workers, 157 day workers). Night work status, cumulative night work duration, and night work intensity were determined through self-report, and cardiometabolic risk factors were assessed through clinical exams. Chronotype was determined using the Munich Chronotype Questionniare (MCTQ). Multiple linear regression was used to examine the association between night work parameters and cardiometabolic risk factors. Current night work, cumulative night work, and night work intensity are associated with a number of cardiometabolic indices, including higher waist circumference, body mass index, fasting glucose, blood pressure, and cardiometabolic risk score. When stratified by chronotype, night work parameters are associated with a number of cardiometabolic risk factors in the evening-oriented chronotype subgroup. There is no difference in cardiometabolic risk factors in morning-oriented chronotypes when comparing night work parameters, with the exception of LDL cholesterol. These results suggest that night work parameters are associated with cardiometabolic risk, and night workers with an evening-oriented chronotype may be more susceptible to the adverse cardiometabolic impacts of night work. Future studies should consider chronotype when examining the relationship between night work and cardiometabolic risk.

KEYWORDS:

• Night work
• chronotype
• cardiometabolic risk

Acknowledgments

We thank the study participants and the investigative team (L. McGillis-Hall, I. Janssen, A.Day, C. Collier), staff (R. Corbin), and the students involved in data cleaning.

Supplementary Material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Canadian Institutes of Health Research;Workplace Safety and Insurance Board (Ontario)