A tendency towards evening chronotype associates with less healthy diet among preschoolers: cross-sectional findings from the DAGIS study

Evidence suggests that adolescents and adults with a later chronotype have poorer sleep habits and are more susceptible to unhealthy behaviors, but, little is known about these associations in younger children. The objective of the study was to 1) identify and compare individual chronotype tendencies among preschool-aged children and 2) investigate associations of sleep dimensions and chronotype with diet. Participants were 636 3–6-years-old (mean±sd age: 4.74±0.89 years, 49%girls) preschoolers from the cross-sectional DAGIS study in Finland. Sleep duration, sleep variability (in duration and midpoint), social jetlag, and midsleep on weekends adjusted for sleep debt (MSWEadj) was measured with 7-day actigraphy. Morning, intermediate, and evening chronotype tendencies were defined based on the lowest and highest 10th percentile cutoffs of MSWEadj. Food, energy, and macronutrient intake were assessed from 3-day records. Associations between sleep dimensions and diet were assessed with regression models. MSWEadj was 1:13±14min for morning (n=64), 2:25±28min for intermediate (n=560) and 3:38±15min for evening (n=64) chronotype tendency. Children with an evening chronotype tendency had greater social jetlag and sleep variability. Having an evening chronotype tendency was associated with higher added sugar, higher sugary food consumption, and lower vegetable consumption compared to intermediate tendency types. A later chronotype (MSWEadj) was associated with higher sugary food consumption, as well as lower vegetable and fiber intake. Sleep duration, social jetlag, and sleep variability were not associated with diet. Several less healthy sleep and diet behaviors were observed among children with later chronotypes. Future public health interventions aimed towards children would benefit from taking into account chronotype.