Changes in chronotype and social jetlag during adolescence and their association with concurrent changes in BMI-SDS and body composition, in the DONALD Study

Bettina Krüger,Sarah Schmitting,Ute Nöthlings,Nicole Jankovic,Anette Buyken,Ute Alexy

doi:10.1038/s41430-021-01024-y

Bettina Krüger, Sarah Schmitting + Show 4 more

Open Access

https://doi.org/10.1038/s41430-021-01024-y

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Abstract

Background/objectivesAdolescence is a critical period for both the development of overweight and the transition toward a later chronotype, often accompanied by an increase in social jetlag. This study assessed whether changes in chronotype and social jetlag, are linked to changes in body composition during adolescence.Subjects/methodsWe used data from the DONALD open cohort study, collected between 2014 and 2019, from 213 adolescents (9–17 years at baseline, 45% females) having at least two measures of chronotype and anthropometry (N = 572). Chronotype was assessed with the Munich Chronotype Questionnaire and defined as: midpoint of sleep corrected for sleep-debt (MSFsc) accumulated over the week (later MSFsc represents later chronotype). Social jetlag (SJL) defines the difference between midpoint of sleep during week and weekend. Calculations for Fat Free Mass Index (FFMI [kg/m2)]) and Fat Mass Index (FMI) [kg/m2)]) were based on body fat percentage, weight, and height. To analyze the associations, we used linear mixed-effect regression models. Finally, the total cohort was split into three biologically relevant age groups (cut-off set at <12 years, ≥12 to ≤15 years and >15 years).ResultsMedian follow-up was 2.1 years. Overall, change toward a later chronotype was significantly related with an increase in FMI (ß: 0.05, 95% CI: 0.01–0.08). A 1 h increase in social jetlag predicted an increase in BMI-SDS of 0.08 SDS units (95% CI: 0.01–0.14) and in FMI of 0.04 kg/m2 (95% CI: 0.003–0.08). Associations were stronger for the age group ≥12 to ≤15 years (p for interaction: <0.001). No relationship was found with FFMI.ConclusionsChanges in MSFsc and SJL during adolescence were associated with concurrent changes in BMI-SDS and FMI. The age ≥12 to ≤15 years appears to be a sensitive period in which chronobiological changes were clearly associated with increasing body fatness.

Highlights

Chronotype describes the individual preference in sleep and wake timing [1]
Our analyses confirm the association between MSFsc or social jetlag (SJL) and body weight status and fat mass as observed in other studies
We could show the strongest associations between Δ MSFsc or Δ SJL and changes in overweight measures like Δ BMISDS and Δ Fat Mass Index (FMI) in the subgroup of adolescents aged 12–15 years

Summary

Introduction

Chronotype describes the individual preference in sleep and wake timing [1]. Misalignment between the individual chronotype and socially determined sleep-wake-schedules result in “social jet lag”, meaning sleep deficits accumulate during the week and result in oversleep during the weekend [2]. Age and sex are important determinants regarding the individual chronotype [3]. The age of 12 years has been identified previously in a German population [4] to mark the start in eveningness, whereas the age of about 16 years represented the peak in lateness [5]. These cut-offs may slightly differ between populations [6]. Having a late chronotype and/or being socially jetlagged during adolescence are two important chronobiological factors, associated with a higher BMI [7,8,9]. Adolescence is considered a critical period for the development of obesity and unfavorable changes of other body composition measures e.g., Fat Mass Index (FMI), likely tracking into adulthood [10, 11]

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