Prospective association between dietary patterns and BMI Z-score in Brazilian adolescents

To identify dietary patterns and prospectively evaluate their influence on the BMI Z-score of adolescents.

A longitudinal study, using data from the Longitudinal Study on Sedentary Behavior, Physical Activity, Eating Habits and Adolescent Health - LONCAAFS.

To obtain data on food consumption, a 24-h recall survey was conducted; a second 24-h recall was applied to 30 % of the sample in all waves. Dietary patterns were identified by exploratory factor analysis using principal components. BMI Z-score was determined according to the recommendation of the WHO, based on the BMI for age and sex. Socio-economic data, sedentary behaviour and physical activity level were obtained. Associations between BMI Z-score and dietary patterns and between BMI Z-score and variables of interest were determined using generalised estimating equations.

Totally, 1431 adolescents were assessed in 2014, 1178 in 2015, 959 in 2016 and 773 in 2017, belonging to the public schools of João Pessoa, Northeast Brazil.

Three dietary patterns were identified throughout the study: 'traditional', 'snacks' and 'Western'. The 'Western' dietary pattern was positively associated with BMI Z-score (β = 0·025; 95 % CI 0·002, 0·048), regardless of sex and physical activity level, prospectively.

A dietary pattern composed of foods with high energy density, high fat and sugars, and low fibre influences the BMI Z-score of adolescents over time.