Endocrine Abstracts

Background and aims: The aim was to compare calcium homeostasis indexes in diabetic and non-diabetic patients with or without fractures.

Materials and methods: We examined 62 postmenopausal women with type 2 diabetes mellitus (DM), 32 of them had bone fracture within last month. The control group included 54 non-diabetic women, 25 within a group were recently fractured. Groups were comparable in body mass index, age, duration of menopause and calcium intake. Diabetic subgroups were comparable in glycosylated hemoglobin level. Tests involved blood and urine calcium and phosphorus, serum parathyroid hormone (PTH), IGF1 and 25-hydroxyvitamin D, C-terminal telopeptide of type I collagen (sCTX) and osteocalcin levels.

Results: In patients with DM without fractures levels of total and ionized calcium were higher compared to women without DM (P<0.01). There also was a reduction of serum calcium in subgroups with fractures (P<0.05). Urine phosphorus excretion in diabetic fracture subgroup was decreased compared to non-fracture one (P=0.002). In both subgroups with fractures was marked reduction of PTH (P<0.01) and vitamin D (P<0.05) compared with women without fractures. Vitamin D level was lower in diabetic groups (P<0.03). No difference in level of IGF1 between all groups was detected. Higher sCTX concentration was registered in non-diabetic women compared to diabetic group (P<0.01). There was a significant decrease of osteocalcin level in both diabetic subgroups (with and without fractures) compared to non-diabetic ones (P<0.01). There was also decrease of osteocalcin concentration in fracture subgroups, but it was relevant only for diabetic group (P=0.03).

Conclusion: Our data indicate that diabetic patients have a lower rate of bone remodeling and predisposed to vitamin D deficiency development. Study results could give a clue to understand previously reported increased fracture risk in diabetic patients, who have higher bone mineral density compared to non-diabetic women.