Purpose: The implication of adolescence diet quality and of certain specific foods' intake on HRQoL remain underexplored, and little importance has been given to biological changes (e.g. growth, maturation, dimorphism, body composition), that remarkably increase the variability of diet and physical activity behaviours. The aim of this study was to analyse the relationship between diet quality and food intake with HRQoL in adolescents, considering maturity, body composition, and physical activity level.
Methods: In total 669 Portuguese adolescents aged 10-17 years, attending three secondary schools, were enrolled in this cross-sectional study. Diet quality was assessed by Diet Quality International-Index (DQI-I), physical activity level was self-reported, and the HRQoL was assessed by the KIDSCREEN-52 questionnaire. The KIDSCREEN-52 includes ten dimensions (physical well-being, psychological well-being, moods and emotions, self-perception, autonomy, parent relations and home life, social support and peers, school environment, social acceptance and bullying and financial resources) and it allowed to compute a general index of the HRQoL (KIDSCREEN-10 index) through a selection of 10 items out of the KIDSCREEN-52 list. Fat mass was obtained by skinfold thickness. Maturity was objectively measured. The level of significance was set at α = 0.05.
Results: Boys scored higher in HRQoL and in physical well-being, self-perception, autonomy, parent relations and home life than girls. Intakes of unhealthy foods were negatively correlated with physical well-being, self-perception, and social acceptance and bullying, while healthy foods were positively correlated with psychological well-being, moods and emotions, self-perception, and school environment. The DQI-I showed to be positively correlated with physical well-being. Participants who reported to have a higher DQI-I (≥ 60) perceived better their school environment and social acceptance and bullying. However, those results were not determined by diet quality but rather by bone age and physical activity level.
Conclusion: Our results showed that boys reported higher HRQoL and higher scores in the majority of HRQoL dimensions, compared to girls. The intake of unhealthy foods was negatively correlated with some HRQoL dimensions, whilst healthy foods showed positive correlations with some HRQoL dimensions. Biological maturity and physical activity level revealed to be important confounders in the study of diet quality and perception of school environment and social acceptance and bullying in adolescents.
Keywords: Biological maturation; Body composition; Bone age; Diet quality; Foods; Health-related quality of life; Maturity offset; Physical activity.