This study aimed to examine diet tracking from childhood to adolescence, using 4 time-points, and the influence of socioeconomic and individual characteristics in this transition. The sample included 6893 children from the Portuguese birth cohort Generation XXI with complete information on Food Frequency Questionnaire in at least one of the considered follow-ups. A Healthy Eating Index (HEI), previously developed to assess adherence to WHO's dietary recommendations, was applied at all ages (4, 7, 10 and 13y). The intraclass correlation coefficient (ICC) was used to analyse the tracking of diet quality. Linear mixed-effect models were performed to estimate the association of the child's socioeconomic and individual characteristics with the HEI score and respective trajectories over time. The overall diet quality decreased from childhood (22.2 ± 3.6 at 4y) to adolescence (18.2 ± 3.9 at 13y), with moderate tracking (ICC = 0.53), showing that children who start a healthy diet earlier might have a better diet quality as time goes by. Children of older mothers (β = 0.079, 95%CI = 0.061-0.097) and with higher education (β = 0.203, 95%CI = 0.178-0.229) and a higher household monthly income (β = 0.024,95%CI = 0.007-0.041) had a higher diet quality over time. Besides family characteristics, the child's sedentary activities (β = -0.009, 95%CI = -0.014--0.003) negatively influence diet quality throughout life. In contrast, being a girl (β = -0.094, 95%CI = -0.132--0.056) and having higher sleep duration (β = 0.039, 95%CI = 0.015-0.064) are associated with a higher diet quality over time. The presence of dietary tracking from childhood to adolescence implies that promoting healthy eating habits during the first years of life is crucial for a healthier diet quality during late childhood and early adolescence, focusing on maternal and individual child characteristics.
Keywords: Adolescents; Children; Dietary quality; Healthy eating; Tracking.
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