A cross-sectional evaluation of the relationship between social jetlag and diet quality

ABSTRACT

The aim of this study was to compare anthropometric measures of obesity and sleep qualities in individuals with/without social jetlag (SJL). In addition, it was aimed to compare the energy, macronutrient intake and diet qualities of individuals with/without SJL during school and non-school days. This study comprised 710 university students with mean age 21.58 ± 1.41 years. The presence of SJL was acknowledged if there was a difference of more than 1 hour between the middle of sleep time on school day and on non-school day. While the physical activity levels (PALs) of the individuals were determined with a 24-hour physical activity record, measurements such as waist circumference, neck circumference and body mass index were recorded for anthropometric measurements. Pittsburgh Sleep Quality Index was used to determine the sleep quality of the individuals. Energy, macronutrients intake, and diet quality were calculated from the 24-h dietary recall of the individuals, and recorded for the school days and non-school days. In this study, 76% of the individuals (n = 542) were determined as exposed to SJL. Although there was no significant difference in their PALs, individuals with SJL had a higher waist (p < .05) and neck (p < .05) circumference, as well as higher body mass index (p < .05). Individuals with SJL were found to have significantly poor sleep quality (OR:1.109, p < .031) and sleep latency (OR:1.130, p < .001) after adjustment for confounding factors. When compared to school days, in the individuals with SJL, energy (p < .001), fat (p < .001), saturated fatty acids (SFA) (p < .001), and mono unsaturated fatty acids (MUFA) (p < .001) were significantly increased; however, fiber intake (p < .001) was significantly reduced on non-school days. Although there was no significant difference in the diet quality scores between the groups on the school days, the diet quality of the individuals without SJL on non-school days was increased significantly (p < .05). In conclusion, SJL was associated with sleep loss, increased body mass index, and lowered diet quality in university students.

KEYWORDS:

• Chrononutrition
• social jetlag
• sleep quality
• diet quality

Acknowledgements

The authors would like to thank the participants for their contribution to the study and Nilsu Dural, Tuğçe Gül Ünal, Sedanur Topkara, Gülseren Özsaç, Yağmur Pınar Akkoyun for their assistance in data collection.

Declaration of interest

The authors declare that there is no conflict of interest.

Authorship

MB designed the study, carried out data collection and analysis and contributed to the draft of the manuscript. BB carried out data collection and analysis and contributed to the draft of the manuscript. AOO finalized the manuscript. All the authors read and approved the final manuscript.

Ethical Standards disclosure

This study was conducted according to the guidelines laid down in the Declaration of Helsinki and all procedures involving research study participants were approved by the ethics committee of Ankara University (Protocol no.56786525-050.04.04/31091). Written informed consent was obtained from all subjects/patients.