SEARCH

SEARCH BY CITATION

OBJECTIVE

Published data on bone metabolism in diabetes mellitus are conflicting. We have measured pyridinium crosslinks, biochemical markers of bone resorption, in order to evaluate bone resorption in diabetes mellitus. We also wished to investigate whether, as a consequence of chronic hyperglycaemia, pyridinoline is glycosylated to a greater extent in patients with diabetes mellitus.

DESIGN AND PATIENTS

This cross sectional study included 142 patients (64 males, 78 females) with insulin dependent and non-insulin dependent diabetes mellitus (IDDM and NIDDM). These patients were compared to a healthy control group of 99 individuals (39 males and 60 females).

MEASUREMENTS

Pyridinium crosslinks, glycosylated, free and total pyridinoline (gPYD, fPYD, tPYD) and free and total deoxypyridinoline (fDPD, tDPD) were measured in a spot urine sample by high performance liquid chromatography (HPLC). Urinary creatinine, albumin and glucose were also measured.

RESULTS

In the diabetic group, values of urinary gPYD and tDPD were significantly lower than in controls. gPYD excretion was lowest in patients with severe glycosuria. Free pyridinium crosslinks, both fPYD and fDPD, were excreted to a significantly lower extent. The molar ratio of tPYD to tDPD was significantly increased in diabetes mellitus.

CONCLUSIONS

Decreased excretion of tDPD suggests low bone resorption in IDDM and NIDDM. Pyridinoline is not glycosylated to a greater extent in diabetes mellitus and tends to be decreased in proportion to the degree of glycosuria. Excretion of gPYD, fPYD and fDPD is depressed in severe glycosuria. Diminished degradation to the final products, fPYD and fDPD, might represent increased resistance to enzymatic activity or diminished enzymatic activity. The increased molar ratio tPYD/tDPD in urine suggests an increased ratio in bone collagen in diabetes mellitus.