Bone densitometry and biochemical bone remodeling markers in type 1 diabetes mellitus

Bone mineral density (BMD) at the lumbar spine, quantified by dual energy X-ray absorptiometry, and biochemical bone remodeling markers (serum alkaline phosphatase, osteocalcin, tartrate-resistant acid phosphatase and urinary hydroxyproline) have been studied in 94 patients with diabetes mellitus aged 18-62 years. BMD was normal (1.13 +/- 0.02 g/cm2 in patients vs. 1.16 +/- 0.12 g/cm2 in controls), although it was found to be negatively correlated with HbA1, microalbuminuria, age and the duration of the disease. Serum alkaline phosphatase (188 +/- 75 I.U./l vs. 168 +/- 42 I.U./1; P < 0.03), serum tartrate-resistant acid phosphatase (14.3 +/- 4.3 I.U./l vs. 11.7 +/- 3.7 I.U./l; P < 0.0001) and urinary hydroxyproline (0.018 +/- 0.016 mmol/mmol creatinine vs. 0.011 +/- 0.008 mmol/mmol creatinine; P < 0.001) were higher in diabetics than in controls. Serum osteocalcin was lower (2.5 +/- 1.3 ng/ml vs. 3.4 +/- 1.2 ng/ml; P < 0.0001). No relationship was found between bone remodeling markers and BMD. It is concluded that lumbar BMD is normal in type 1 diabetic patients, although the degree of metabolic control, age and duration of the disease may affect it. In the light of the biochemical markers, bone remodeling may be disturbed in diabetes, but such disturbance seems to be unimportant regarding BMD.