Associations between chronotype, diet quality and timing of energy intake in Portuguese children and adolescents: The potential role of summer holidays.

Later chronotypes may be associated with lower diet quality and later timing of energy intake in paediatric age. Period of data collection of these variables may affect these parameters and inter-relationship. We aimed to assess the cross-sectional association of chronotype with a diet quality score (HEI) and caloric midpoint (time of achieving 50% of total daily energy intake), considering summer holidays, using data from the National Food, Nutrition and Physical Activity Survey 2015-2016 for 578 participants (6-14 years of age). Chronotype was estimated by the midpoint of sleep and categorized as Early, Intermediate and Late, using physical activity diaries, while outcomes using two food diaries/24 h recalls. Associations of chronotype with outcomes were assessed by linear regressions adjusted for sex, age, parental education (model 1), BMI, sports practice (model 2), and summer holidays (no/yes) (model 3). In model 2, a Late vs. Early chronotype was negatively associated with HEI (βˆ = -0.74; 95% CI: -1.47, -0.07) and positively with caloric midpoint (βˆ = 0.35; 95% CI: 0.02, 0.69). However, associations lost significance in model 3. The association between chronotype and dietary habits may be benefit from being studied considering school terms and summer holidays. Future larger prospective studies are needed to clarify the role of summer holidays on this inter-relationship.