Bone Mass and Density in Youth with Type 2 Diabetes, Obesity, and Healthy Weight

Objective: Youth-onset type 2 diabetes is an aggressive condition with increasing incidence. Adults with type 2 diabetes have increased fracture risk despite normal areal bone mineral density (aBMD), but the influence of diabetes on the growing skeleton is unknown. We compared bone health in youth with type 2 diabetes to controls with obesity or healthy weight.

Research Design and Methods: Cross-sectional study of youth (56% African American, 67% female) ages 10-23 years with type 2 diabetes (n=180), obesity (BMI>95^th; n=226), or healthy weight (BMI<85^th; n=238). Whole body (less head) aBMD and lean mass, and abdominal visceral fat were assessed via DXA. Lean body mass index (LBMI) and aBMD standard deviation (SD) scores (“Z-scores”) were computed using published reference data.

Results: We observed age-dependent differences in aBMD and LBMI Z-scores between the healthy weight, obese, and type 2 diabetes groups. In children, aBMD and LBMI Z-scores were greater in the type 2 diabetes vs obese groups, but in adolescents and young adults, aBMD and LBMI Z-scores were lower in the type 2 diabetes vs. obese group (age interactions P<0.05). In the type 2 diabetes and obese groups, aBMD was about 0.5 SDs lower for a given LBMI Z-score compared to healthy weight controls (P<0.05). Further, aBMD was lower in those with greater visceral fat (β=-0.121, P=0.047).

Conclusions: These results suggest that type 2 diabetes may be detrimental to bone density around the age of peak bone mass. Given the increased fracture risk in adults with type 2 diabetes, there is a pressing need for longitudinal studies aimed at understanding the influence of diabetes on the growing skeleton.