Kelley JC, et al. - This study contemplated the variations in trabecular and cortical volumetric bone mineral density (vBMD) and cortical geometry in obese adolescents undergoing a randomized weight management program. In addition, it gauged the impact of body composition changes on bone outcomes. It was duly noted that the weight loss intervention with modest changes in body mass index (BMI) was not detrimental to radius or tibia bone strength, in obese adolescents. The variations in lean but not adiposity, measures were beneficial to bone development.

Methods

• The study yielded peripheral quantitative CT of the radius and tibia, and whole body DXA scans at baseline, six and 12 months.
• The enrollees included 91 obese adolescents randomized to standard care versus behavioral intervention for weight loss.
• Longitudinal models examined the effects of body composition changes on bone outcomes, adjusted for age, bone length, and African-American ancestry, and stratified by sex.
• Secondary analyses comprised of adjustment for physical activity, maturation, vitamin D, and inflammatory biomarkers.
• Similar baseline BMI was noted among the intervention groups.

Results

• 12-month variation in BMI in the standard care group was 1.0 kg/m² vs. -0.4 kg/m² in the behavioral intervention group (p < 0.01).
• There were similar intervention groups in bone outcomes, which were combined for subsequent analyses.
• For the tibia, there was no link between BMI change with change in vBMD or structure.
• Greater baseline lean body mass index (LBMI) was related to higher cortical vBMD in males, trabecular vBMD in females, and polar section modulus (pZ) and periosteal circumference (Peri-C) in both sexes.
• In females, change in LBMI exhibited a positive correlation with gains in pZ and Peri-C.
• An inverse link was reported between baseline visceral adipose tissue (VFAT) with pZ in males and cortical vBMD in females.
• The VFAT variations did not affect bone outcomes.
• BMI and LBMI changes positively correlated with pZ in males, for the radius.