Bone Mineral Density at Time of Clinical Diagnosis of Adult-onset Type 1 Diabetes Mellitus

Objective: To study bone mineral density (BMD) and bone remodeling factors at the time of diagnosis of adult-onset type 1 diabetes mellitus (DM).

Methods: In 22 men and 10 women, who ranged in age from 20 to 39 years, a study was undertaken promptly after diagnosis of type 1 DM (on the basis of criteria established by the World Health Organization). Before any treatment, the clinical history, glycemia, ketonuria, basal and glucagon-stimulated C-peptide levels, islet cell antibodies (ICA), glutamic acid decarboxylase autoantibodies (GADA), and bone remodeling variables were recorded for all the study subjects. Dual-energy x-ray absorptiometry (Hologic QDR1000) was performed to measure BMD in the lumbar spine (LS), femoral neck (FN), and Ward's triangle.

Results: Of the 32 patients, 24 (75%) showed positive levels of ICA or GADA (or both), whereas 8 (25%) tested negative. The BMD values-Z-scores (standard deviation [SD] adjusted for age and sex)-were lower among the patients with DM than in a matched healthy population in both the LS (-0.61 +/- 1.23 SD; P = 0.008) and the FN (-0.38 +/- 1.00 SD; P = 0.003). Twelve patients had a T-score between -2.5 SD and -1 SD in the LS, and 14 had the same scores in the FN and were classified as having osteopenia. A correlation was found between BMD values and C-peptide levels in the LS (r = 0.231; P = 0.02) and the FN (r = 0.27; P = 0.01). The BMD values did not correlate with bone remodeling markers, hemoglobin A1c, or immunologic variables.

Conclusion: We found reduced bone mass in patients with type 1 DM at the time of the clinical diagnosis. A high percentage of patients with DM have osteopenia, which may not, therefore, be a late complication of type 1 DM. These findings need to be confirmed in larger studies.