RESUMEN
PURPOSE: The present study aimed to explore the influence of diet and physical activity (PA) changes on bone mineral content (BMC) and density (BMD) alterations in adolescents with obesity undergoing a weight loss program. METHODS: Six-month longitudinal data from 71 adolescents (aged 15.1 [± 1.6] years; 57.7% girls) with a BMI z-score of 3.03 (± 0.78), previously recruited for the PAC-MAnO trial, were analyzed using Generalized Estimation Equations for over time changes and linear regressions with BMC, BMD and BMD z-score as dependent variables, adjusting for confounders (including type of exercise- aerobic vs. combined). RESULTS: Adjusting for confounders, changes in carbohydrate (CH) and protein content showed to positively and negatively predict BMD z-score variance, respectively (ß = 0.44, 95%CI: 0.01, 0.04, p < .001); ß = -0.57, 95%CI: -0.06, -0.03, p < .001), yet no associations were found between PA and bone-related parameters. Combined exercise showed better results on BMC compared to aerobic exercise (ß = 0.09, 95%CI: 0.05 to 0.13, p < .001). CONCLUSIONS: Increased CH content, instead of protein, may be associated with BMD improvements in adolescents with obesity. Type of exercise may moderate the impact of PA on bone health. TRIAL REGISTRATION: Clinicaltrials.gov NCT02941770. What is Known ⢠Adolescents with obesity may be at a higher risk of osteopenia/osteoporosis ⢠Obesity and inadequate diet and physical activity (PA) may have an adverse effect on bone metabolism What is New ⢠Improvements in adiposity and muscle mass and increased diet carbohydrate content are associated with bone mineral density (BMD) improvements ⢠Type of exercise (i.e., combined training vs. aerobic) may moderate the impact of PA on BMD, and calcium intake may mediate this impact.