A combined dietary-physical activity intervention affects bone strength in obese children and adolescents

Obesity has become the most common pediatric chronic disease in the modern era. Recent data suggests that unlike obese adults, obese children and adolescents may have decreased bone strength. It was the objective to prospectively examine the short term effects of a 3 month combined dietary-physical activity intervention on anthropometric measures, body composition, fitness and bone strength in obese children. Twelve obese subjects completed the 3 m intervention and were compared to 12 obese age and gender matched controls. Bone strength was measured using quantitative ultrasound measurements of bone speed of sound (SOS). There were significant differences in changes of body weight (0.01 ± 0.7 vs. 2.3 ± 0.6 kg, p = 0.033), BMI percentiles (-2.8 ± 1.1 vs. -0.2 ± 0.2%, p = 0.037), body fat percent (by skinfolds, -1.5 ± 0.8 vs. 0.7 ± 0.5%, p = 0.035), and endurance time (170 ± 42 vs. 50 ± 27 s, p = 0.045) in the intervention vs. control subjects, respectively. In addition, we found a significant difference in the change of bone SOS between the intervention and control group subjects (21.5 ± 21.6 vs. -87.0 ± 37 m/s, p = 0.023). During the critical period of bone development of childhood and adolescence, a combined dietary-physical activity intervention leads to increased bone strength in obese children. These results highlight the importance of multi-disciplinary programs for the treatment of childhood obesity and its complications.