Consumo de desjejum e de desjejum em família, e adiposidade na adolescência: uma coorte de base escolar.

Abstract

The current thesis describes the role of breakfast frequency and of family breakfast on adiposity in adolescence, as well as the trajectory of breakfast frequency and foods / food groups often consumed in this meal. We evaluated adolescents from two public and four private schools from Rio de Janeiro metropolitan region, participants of the Adolescent Nutritional Assessment Longitudinal Study (ELANA). The students were selected in 2010 (n = 809) and followed for three years. For the current thesis, we used data from middle school students that originated two manuscripts. In manuscript I, the effects of breakfast and family breakfast on body mass index (BMI) and body fat percent (%BF) trajectories were analyzed by linear mixed-effect models for repeated measurements. Overall, no significant effect of the exposure variables on adiposity was detected. However, a higher increase in %BF was found among girls who had more frequent breakfast in both baseline and persistent after three years, and among those with frequent family breakfast, compared to irregular consumption. Boys who reduced or increased family breakfast frequency in three years showed greater decrease in %BF in relation to those who maintained irregular consumption. In manuscript II, generalized estimating equations with log-binomial models for repeated measurements were used to estimate changes in breakfast frequency in three years according to baseline characteristics, and with multinomial models, to assess changes in foods/food groups often consumed at breakfast. Among girls, increased risk of irregular breakfast or breakfast skipping was verified after three years. We found a higher risk of irregular breakfast frequency after three years among overweight boys and among non-overweight girls. While boys had a higher risk of decreased consumption of fruits, snacks, chips and ham and lower risk of decreased cheese consumption, girls had higher risk of decreased consumption of fruits, milk, chocolate powder and ham in three years. This thesis contributes to the understanding of the role of breakfast and family breakfast on adiposity, as well as to the characterization of breakfast among adolescents in the Brazilian context.