OBJECTIVES

Poor control of blood glucose levels in patients of Diabetes Mellitus often results in low bone mineral density. The reason for this decrease in bone mass is at present uncertain. In this study, we evaluated correlation of calcium metabolism with blood glucose levels and normal renal function.

METHODS

: A total of 130 diabetic patients (35 Type 1, 95 Type 2) were enrolled in this study. In all patients plasma calcium (Ca), serum phosphate (PO4), serum parathyroid hormone (PTH), and 24-h urinary calcium (uCa) were determined under both poor and improved control (for at least 7 days) as ascertained by four blood glucose determinations daily.

RESULTS

: Improvement of blood glucose level was associated with reduction of uCa both in Type 1 (6.7 +/- 1 vs 5.0 +/- 0.9 mmol/day) and in Type 2 patients (4.3 +/- 0.4 vs 3.1 +/- 0.4 mmol/day). It was also found that considerably more Type 1 patients (15 out of 35) had PTH values below the detection limit (1.5 pmol/l) during poor than during improved control (4 out of 35). Type 2 patients also showed this difference but to a lesser extent. 33 out of 95 type 2 patients had PTH level below detection limit during poor control as compared to only 5 patients during good control. Comparison between the two types of diabetes showed that in Type 1 under poor control, Ca and PTH were lower, while uCa was higher, and after improved control, only uCa continued to be higher.

CONCLUSIONS

: Increased uCa excretion and decreased PTH levels are associated with uncontrolled blood glucose levels (especially in Type 1 diabetes). Therefore decreased serum PTH levels in uncontrolled Diabetes Mellitus may be one of the factors leading to reduced bone mass. Hence it is justified to call Diabetes Mellitus a synonym to functional hypoparathyroidism.