Comparing different approaches to assess individual chronotypes in epidemiological studies (SEVERUS-Cohort)

ABSTRACT

Assessing individual chronotypes can become relevant for epidemiological studies, for instance when investigating the impact of night-shift work on human’s health. The objective of this study was to explore and compare three different approaches (Self-rating, Munich Chronotype Questionnaire (MCTQ), Perfect Day (PD)) of assessing the chronotype in a group of 48 police officers. We compared the categorical classification of self-rated chronotypes with Mid Sleep Times (MST) on free days from the MCTQ and MST on PDs. Chronotype categories derived from self-rating were only weakly associated with the MST derived from free days (Spearman’s rho = 0.33, p = 0.078) and PDs (rho = 0.26, p = 0.073). We found a positive correlation between the MSTs assessed via MCTQ and PD (Pearson’s r = 0.67, p < 0.001). There were differences in the MST on free days and on PDs between individuals who did and did not use an alarm clock. All three approaches to assess chronotype information have to be used with caution. Concerns of selection and misclassification bias are raised when assessing chronotypes through the MST on free days for those who do not use alarm clocks. Further research is needed to develop sound strategies to assess chronotypes in epidemiological studies.

KEYWORDS:

• Shift work
• Munich Chronotype Questionnaire
• perfect day
• epidemiological studies
• circadian rhythm

Acknowledgments

The authors thank the study participants and their superior body for supporting the study.

Furthermore, we thank the IPAUP clerical team for data organization and management.

Contributorship statement

JVG, AP, UW and TCE planned the study. JVG and IS conducted the study. JVG, MH, IS and RR conducted the statistical analyses. The first draft was created by JVG and revised and discussed by all authors.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. The name was chosen following Severus from Ravenna, policemen’s patron saint.

Additional information

Funding

This research received no specific grant from any funding agency in the public, commercial or nonprofit sectors.