ESPE Abstracts

Objectives: Previous studies have shown an increasing percentage of obese children with fractures. Visceral fat mass (VFM) volume and metabolic disorders have already been recognized as negative predictors for bone mineral density (BMD) in adolescents.

Methods: Study participants included 41 adolescent girls aged 14-17 who were divided into two groups according to body mass index (BMI) percentile (P) - group 1: 8 overweight girls (P85– < P95) and 17 girls with moderate obesity (100%–120% of P95) and group 2: 9 girls with severe obesity (120%–140% of P95) and 7 girls with extreme obesity (>140% of P95). DXA bone densitometry with body composition measurements and bioimpedans (BI) analysis were performed. Laboratory markers for glycemic control, including oral glucose tolerance test and biochemical panel were investigated.

Results: Whole body BMD was significantly higher (2.1 SD vs 1.4 SD) in the girls from group 2 and was positively correlated with body weight, BMI and all parameters of fat mass and fat free mass. Bone mineral content to lean body mass ratio (BMC/LBM) and bone area/height (BA/height) were significantly lower in the girls from group 2 - P56.2 vs P38.4 and P36 vs P28, respectively. Both BMC/LBM and BA/height showed significant negative correlation with total fat mass, VFM, waist circumference, the obesity degree and the BI’s indices for metabolic status (VF level, InBoby score). Half of the girls with severe and extreme obesity had BA/height less than P10. In the same group, the arms’ BA was significantly lower and the arms’ fat mass to lean mass ratio (FM/LM) was significantly higher and negatively correlated with both BMC and BA. We didn’t find any significant correlations for the lumbar spine BMD/BMC with body composition components and there were no significant differences in its values between the two groups. We found a significant positive correlation between whole body BMD and HbA1c, fasting insulin and uric acid levels. All the girls showed suboptimal 25(OH) vitamin D levels, which were lower in the girls with severe and extreme obesity.

Conclusion: Adolescent girls with severe or extreme obesity have lower BMD and lower BA compared to girls with overweight and moderate obesity. The normal study girls’ mean height (P70) suggests a deficit in the bone diameter growth. The higher arms’ FM/LM ratio negatively influences arms’ BMC which may contribute to the increased forearm fracture rate. VFM, but no metabolic markers, is negatively correlated with bone growth parameters.