[Association between excessive TV viewing time and body mass index among Brazilian adolescents: quantile regression analysis of the National Student Health Survey (PeNSE), 2015].

The study aimed to investigate whether excessive TV viewing time is associated with body mass index (BMI), irrespective of physical activity (PA) and interaction with consumption of ultra-processed foods (UPFs), among Brazilian adolescents. It is a cross-sectional study with data on 13-17-year-old adolescents from the 2015 National Student Health Survey. BMI was the outcome (direct measurement of height and body mass) and exposure was excessive TV viewing time (>2 h/day), daily consumption of UPFs and PA. Quantile regression was used to test associations and interactions. Excessive screen time was associated with higher BMI values (e.g., 25th percentile =0.060 kg/m² versus 95th percentile =0.891 kg/m², p<0.001). After adjusting for PA, the association remained, however, attenuated. The inclusion of UPFs in the model potentiated the association (e.g., 25th percentile =0.062 kg/m² versus 95th percentile =0.956 kg/m², p<0.001). Excessive screen time was associated with BMI percentiles, irrespective of PA - the absence of PA and the presence of UPF consumption affect the upper BMI percentiles more. Actions to reduce excessive TV viewing time, consumption of UPFs and promoting PA are essential to positively impact BMI and its reflexes on the health of Brazilian adolescents.