Bone Mineral Density in Normal-Weight, Overweight and Obese Children and Its Association with Body Composition

Abstract

Objectives Examine the differences in bone mineral density between normal-weight children and children with overewight or obesity and its association with body composition. Methods In a cross-sectional study, 49 healthy schoolchildren from 6 to 11 years of age attending the outpatient clinic of the Hospital were included. Weight and height were measured for the calculation of the body mass index for age and height for age. The diagnosis of normal-weight, overweight and obesity was made according to the criteria of the World Health Organization. Bone mineral density (BMD) was obtained by dual energy X-ray absorptiometry (DXA). Statistic analysis. The ANOVA test was used to compare mean values between groups. Pearson's correlation to analyze the relationship between BMD and body composition; and multiple regression models to identify associated variables. Results Mean age 8.4 ± 1.7 years; 16 with normal weight, 15 overweight and 18 with obesity. All children had a normal BMD (>–2 Z score). BMD (g/cm2 and Z score) was higher in children with obesity (p < 0.05). Bone mineral content (BMC [g]) and BMD (g/cm2) had a positive correlation with total lean and trunk mass in the three groups (p < 0.001). Fat mass correlated with BMC and BMD in children with normal-weight and overweight, but not in obese children. In multivariate models, total lean mass was the only significant variable within the model that explained the variability of BMD (g/cm2). Conclusions BMD was higher in children with obesity. Lean mass was its most important predictor, which suggests the importance of maintaining the muscular system through the practice of physical activity and healthy lifestyles. Funding Sources Universidad de Guadalajara; Hospital Civil de Guadalajara; Consejo Nacional de Ciencia y Tecnología de México.