RESUMEN
BACKGROUND: Increasing consumption of ultra-processed foods (UPF) has been identified as a risk factor for obesity and various diseases, primarily in adults. Nonetheless, research in children is limited, especially regarding longitudinal studies with metabolic outcomes. We aimed to evaluate the longitudinal association between consumption of UPF, adiposity, and metabolic indicators in Chilean preschool children. METHODS: We conducted a prospective analysis of 962 children enrolled in the Food and Environment Chilean Cohort (FECHIC). Dietary data were collected in 2016 at age 4 years with 24-h recalls. All reported foods and beverages were classified according to the NOVA food classification, and the usual consumption of UPF in calories and grams was estimated using the Multiple Source Method. Adiposity (z-score of body mass index [BMI z-score], waist circumference [WC], and fat mass [in kg and percentage]) and metabolic indicators (fasting glucose, insulin, HOMA-IR, triglycerides, total cholesterol, and cholesterol fractions) were measured in 2018, at the age of 6 years. Linear regression models ((0) crude, (1) adjusted for covariables, and (2) adjusted for covariables plus total caloric intake) were used to evaluate the association between UPF and outcomes. All models included inverse probability weights to account for the loss to the follow-up. RESULTS: At 4 years, usual consumption of UPF represented 48% of the total calories and 39% of the total food and beverages grams. In models adjusted for covariables plus caloric intake, we found a positive association between UPF and BMI z-score (for 100 kcal and 100 g, respectively: b = 0.24 [95%CI 0.16-0.33]; b = 0.21 [95%CI 0.10-0.31]), WC in cm (b = 0.89 [95%CI 0.41-1.37]; b = 0.86 [95%CI 0.32-1.40]), log-fat mass in kg b = 0.06 [95%CI 0.03-0.09]; b = 0.04 [95%CI 0.01-0.07]), and log-percentage fat mass (b = 0.03 [95%CI 0.01-0.04]; b = 0.02 [95%CI 0.003-0.04]), but no association with metabolic indicators. CONCLUSIONS: In this sample of Chilean preschoolers, we observed that higher consumption of UPF was associated with adiposity indicators 2 years later, but not with metabolic outcomes. Longer follow-up might help clarify the natural history of UPF consumption and metabolic risks in children.