Soft drink consumption and body mass index in Brazilian adolescents: National Adolescent Student Health Survey.

Objective: To estimate the association between soft drink consumption and body mass index (BMI) in eutrophic and overweight adolescents.
Methods: We used data from the National Adolescent Student Health Survey (Pesquisa Nacional de Saúde do Escolar - PeNSE) of 2009. The dependent variable (outcome) was the tertiles of BMI score (zBMI), and the main independent variable (exposure) was the consumption of sugar-sweetened soft drinks. The models included age, school type, home goods and services score, and maternal schooling as adjustment variables. We estimated the association between exposure and outcome by using multinomial regression models, stratified by gender, and eutrophic and overweight subgroups.
Results: 23.8% of the adolescents evaluated were overweight, and 21.7% reported consuming soft drinks daily. For eutrophic boys, those who consumed soft drinks had a greater chance of being in higher zBMI tertiles than non-consumers. For overweight adolescents, both male and female, soft drink consumption was associated with a lower chance of being in the highest tertile of zBMI score.
Conclusion: The results show the possibility of reverse causality between consumption of sweetened soft drinks and zBMI in the overweight adolescents group. For eutrophic male adolescents, soft drink consumption can potentially increase the chances of having higher zBMI, which reinforces the need for measures to significantly reduce the consumption of this beverage.