Correlations between bone mineral density and circulating bone metabolic markers in diabetic patients

Diabetic osteopenia, a known chronic complication of diabetes, has been dem onstrated with alterations in the calcium-vitamin D endocrine system. In or der to investigate the relationship between the decrease of bone density an d the altered mineral metabolism in non-insulin-dependent diabetes mellitus (NIDDM), 104 male clinical-proven NIDDM patients were studied. All patient s were examined on metacarpal bone mineral density (m-BMD) by means of comp uted X-ray densitometry (CXD) methods. The values of the Z-score of m-BMD w ere significantly lower than those of age-matched controls (P < 0.01). Ther e was a positive correlation between m-BMD and serum calcium levels (P < 0. 01), but a negative correlation was conversely observed between m-BMD and s erum intact parathyroid hormone (PTH) (P < 0.01), indicating that the negat ive calcium balance under diabetic conditions could cause the decrease of m -BMD in NIDDM. Interestingly, since a significantly positive correlation wa s found between circulating levels of calcium and parathyroid hormone-relat ed peptide (PTHrP) (P < 0.05) but not PTH, it seems likely that PTHrP plays a more compensatory role on the maintenance of calcium homeostasis than PT H under diabetic conditions. Based on these observations, the CXD method wo uld be useful in measuring the mineral density of cortical bone, and would also be beneficial to investigate underlying pathogenetic mechanism of diab etic osteopenia. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved .