Chronotype Profile in Children: A Systematic Review

The chronotype profile of children has been described over the years, but the data regarding the subject is inconsistent in the literature. Some studies have shown that the morning type is the predominant chronotype in children, while others have indicated that neither or evening type children are the majority. To our knowledge, no systematic reviews concerning chronotype in children have been performed before. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed in conducting this review. The literature search was performed between November 2022 and June 2023, targeting studies that described children’s chronotype in the following databases: PubMed, Embase, Web of Science, LILACS, and SciELO. Eligibility criteria included studies that assessed chronotype—either objectively or subjectively, mid-sleep point or circadian preference—among children aged 0–10 years. 62 studies were included in this systematic review. The most commonly used variables for children’s circadian evaluation were Mid-sleep point and Circadian Preference. Most of these studies showed a higher prevalence of neither type chronotype. Associations between evening type and social jet lag were found, suggesting that there is a misalignment between biological and social characteristics in these children. Some studies also found shared chronotype preference between parents and their children. Most studies were cross-sectional and measure children’s chronotype subjectively. A lack of longitudinal studies and objective data was observed. More longitudinal studies are necessary to define circadian profile throughout infancy and to explore the impact of environmental factors in human chronotype.