Influence of the weight status on bone mineral content and bone mineral density in a group of Lebanese adolescent girls

Abstract

Aim The aim of this study was to determine the influence of being overweight on whole-body (WB) bone mineral content (BMC) and bone mineral density (BMD) in a group of Lebanese adolescent girls. Methods This study included 32 overweight (BMI > 25 kg/m2) adolescent girls (15.3 ± 2.3 years old) and 24 maturation-matched (15.7 ± 1.7 years old) controls (BMI < 25 kg/m2). Bone mineral area (BMA), BMC, BMD at the WB and body composition (lean mass and fat mass) were assessed by dual-energy X-ray absorptiometry (DXA). Calculation of the ratio BMC/height and bone mineral apparent density (BMAD) were completed for the WB. Results Expressed as crude values, BMA, BMC and the ratio BMC/height were higher in overweight adolescent girls compared to controls. After adjusting for body weight, there were no differences in BMC or in the ratio BMC/height between the two groups. However, BMA was lower in overweight girls compared to controls. After adjusting for either lean mass or fat mass, there were no significant differences between the two groups regarding these variables: BMC, BMA, BMD, BMC/height and BMAD. Conclusion This study suggests that the positive effect of overweight on BMC is due to body weight. In fact, the difference in BMC between the overweight and the control girls disappears after adjusting for body weight. In contrast, overweight girls have lower BMA compared to controls when values are adjusted to body weight.