Overweight/obesity in adolescents with phenylketonuria: protective and predisposing factors

OBJECTIVE: To estimate the prevalence and factors associated with overweight/obesity development in adolescents with early diagnosed phenylketonuria treated exclusively by diet. METHODOLOGY: In this cross-sectional study anthropometric measurements, serum phenylalanine levels, and 10 metabolites associated with lipid and carbohydrate metabolism were analyzed in 101 adolescents aged 10–20 years. Adolescents were categorized into overweight/obesity and eutrophic/low body mass index groups. These patients were compared using Student's t-test, Pearson's chi-square test, Wald's chi-square test for multivariate analysis. Further, to verify whether the prevalence of overweight/obesity found in the study population was similar to that in the general population, the authors compared the nutritional status of 46 patients aged 13–17 years with that of healthy students of the same age from the National School Health Survey using the chi-square test for adherence. The significance threshold was p < 0.5. RESULTS: The prevalence of overweight/obesity in adolescents was 27.7%. There was no difference in prevalence between sexes. Older age was a protective factor and Increased Homeostasis Model Assessment Insulin Resistance index and high phenylalanine and low-density lipoprotein cholesterol levels were predictive factors for overweight/obesity. The equality hypothesis was not rejected in the comparison of nutritional states of 46 patients aged 13–17 years and healthy students of the same age. CONCLUSION: The prevalence of overweight/obesity in phenylketonuria adolescents was similar to what is found in healthy adolescents.