Bone mineral acquisition in adolescents with type 1 diabetes

Objective

To track bone mineral acquisition in adolescents with type 1 diabetes (DM).

Study design

Subjects were adolescents, ages 12 to 18 years, with DM (n=42) and a healthy regional reference (n=199). Measurements of tibia bone characteristics by peripheral quantitative computed tomography (pQCT) and spine and whole body (WB) by dual-energy x-ray absorptiometry (DEXA), anthropometrics, and lifestyle questionnaires were obtained during a 12-month period. Disease duration, insulin dose, renal function, and glycosylated hemoglobin (HbA1c) values for the previous 12 months were recorded.

Results

Body size and maturation were similar between groups. DM had lower tibia, spine, and WB bone characteristics but greater muscle mass (LBM) and lower bone mineral content (BMC)/LBM at baseline and 12 months. Annual gains for tibia cortical bone and WB BMC/LBM were lower and inversely related to HbA1c levels (R=−0.36 to −0.51), whereas spine area and density and WBLBM were greater and were predicted by pubertal-driven growth. Overall, the DM cohort had 8.5% less WB BMC/LBM, suggesting that bone mineral deposition was not adequately adapted to muscle gains.

Conclusions

Adolescents with type 1 diabetes continue to have smaller bone mass and bone size despite normal growth and maturation. Poor metabolic control appears to negatively influence bone mineral acquisition.

aBMD, Areal bone mineral density (g/cm²), BA, Bone area (cm² or mm²), BAP, Bone-specific alkaline phosphate, BMC, Bone mineral content (g), BMC/LBM or MCSA, Bone mass or strength to muscle size ratio, BMAD, Bone mineral apparent density, DM, Type 1 diabetes mellitus, DEXA, Dual-energy x-ray absorptiometry, LBM, Lean body mass, HbA1c, Glycosylated hemoglobin A1c, LBM or MCSA/height, Muscle size or strength to height ratio, MCSA, Muscle cross-sectional area, MET, Metabolic cost of activity, pQCT, Peripheral quantitative computed tomography, SSI, Strength-strain index, vBMD, Volumetric bone mineral density