Bone Mineral Content and Density in Obese, Overweight, and Normal-Weighted Sedentary Adolescent Girls

Purpose: The aim of this study was to compare the whole body (WB) bone mineral content (BMC) and bone mineral density (BMD) in obese, overweight, and normal-weighted adolescent sedentary girls. Methods: This study included 17 obese, 27 overweight, and 21 normal-weighted adolescent (aged, 12-20) sedentary (practicing less than 2 hours of physical activity/week) girls. The three groups (obese, overweight, and normal) were matched for age and maturation index (years since menarche). BMC, bone mineral area (BMA), BMD, and body composition were assessed by dual-energy X-ray asborptiometry. Bone mineral apparent density (BMAD) was calculated for the WB. Results: Obese girls had higher BMC values than overweight and normal-weighted girls (p<.05 and p<.001, respectively). Overweight girls had higher BMC values than normal-weighted girls (p<.05). BMD values were not different among the three groups. However, obese and overweight girls had lower BMAD and higher BMC/height values in comparison with normal-weighted girls (p<.05). Finally, after adjustment for lean mass, BMC, BMA, BMD, and BMAD were not different among the three groups. Conclusion: In this population, overweight and obesity are associated with higher BMC, BMC/height, and lower BMAD of the WB. This study suggests that BMD, BMC, BMA, and BMAD of the WB are not significantly different among the three groups (obese, overweight, and normal) after adjustment for lean mass. Therefore, our results suggest that the skeleton of the overweight and the obese girls adapts to the increased lean mass. (C) 2010 Society for Adolescent Health and Medicine. All rights reserved.