Tendência secular, ganho rápido de peso e sua associação com trajetórias de crescimento infantil: estudo de coorte de 9 milhões de crianças brasileiras

Abstract

Introduction: Obesity is considered a disease with negative impacts on health throughout all life cycles. The dynamics of linear and weight growth can have important repercussions for health and monitoring them over short periods can have significant population implications. On the other hand, changes in growth rate, such as rapid weight gain, can be important predictors of children's growth trajectories, especially when they occur in the postnatal phase. Thus, the primary care level represents a promising platform for early prevention of obesity, increasing the chances of prevention and population control of this disease. Objectives: To analyze the BMI and height trajectories in Brazilian children aged 3 to 10 years according to two generations born between 2001 and 2007 and born between 2008 and 2014. To analyze the BMI trajectories according to rapid weight gain in the first 2 years in children aged 3 to 10 years. Methods: This is a retrospective cohort that used secondary data from the Federal Government's Single Registry (CadÚnico), data from the national live birth system (SINASC) and the national nutritional and food surveillance system (SISVAN). These databases make it possible to compose an unprecedented empirical data base on the Brazilian population called a cohort of 100 million Brazilians. The sample is sized at approximately 9 million Brazilian children aged 0 to 10 years between 2008 and 2017. The mixed effects model with fractional polynomials was used to estimate the BMI and height trajectories. Data analyzes were carried out using the R software. Results: It was observed that there is a small significant increase in the average BMI in children born between 2008-15 when compared to those born between 2001-07 for both boys (0.05 kg/m2 ) and for girls (0.07 kg/m2). There was also a small significant increase in the average height between the two cohorts, with the average increase in height being similar between the sexes, being 1.03 cm for boys and 1.07 cm for girls. Children who presented GRP during the first two years of life had a mean BMI trajectory from 3 to less than 10 years that was higher than those without GRP. The average difference increased with age, and for boys the difference was 0.04 kg/m2 at 3 years, 0.23 kg/m2 at 6 years and 0.48 kg/m2 at 10 years. In girls, the differences were very similar to those in boys, being 0.08 kg/m2 at 3 years old, 0.23 kg/m2 at 6 years old and 0.45 kg/m2 at 10 years old. Conclusion: The evidence found in this study indicates that there is a positive secular trend towards an increase in height trajectories and BMI trajectories in recent generations, although the increase has been quite discrete for BMI. It was also shown that children who showed rapid weight gain during the first two years of life had higher BMI trajectories than those without rapid weight gain. Additionally, the difference between children who did and did not experience rapid weight gain increased with age