Association of serum osteoprotegerin with vascular calcification in patients with type 2 diabetes

The subjects were 124 patients with type 2 diabetes mellitus, including 88 males and 36 females with a mean (± SD) age of 65.6 ± 8.2 years old. Serum levels of osteoprotegerin, osteocalcin, fibroblast growth factor 23 (FGF23), 25-hydroxyvitamin D3 and adiponectin were measured by ELISA. Vascular calcification in the cervical artery was examined by ultrasound sonography. The subjects were divided into 4 quartiles depending on serum osteoprotegerin levels.Vascular calcification was significantly higher in the 4th quartile and significantly lower in the 1st quartile of serum osteoprotegerin levels, compared to other quartiles. There were no differences in serum osteoprotegerin and vascular calcification among patients with different stages of diabetic nephropathy, but serum FGF23 levels were elevated in those with stage 4 diabetic nephropathy. Simple regression analysis showed that serum osteoprotegerin levels had significant positive correlations with age, systolic blood pressure and serum adiponectin levels, and significant negative correlations with BMI and serum 25-hydroxyvitamin D3.These findings suggest that elevated serum osteoprotegerin may be involved in vascular calcification independently of progression of diabetic nephropathy in patients with type 2 diabetes.Atherosclerosis, macroangiopathy and microangiopathy are major prognostic factors in diabetes. Vascular endothelial impairment is the initial pathological change and is profoundly involved in development of atherosclerosis [1-4]. Progression of diabetic nephropathy, including microalbuminuria, is a risk factor for atherosclerosis in type 2 diabetes mellitus [5,6] and diabetic patients with advanced nephropathy (particularly those on dialysis with end-stage kidney disease) often have vascular calcification [7-10]. However, the duration of diabetes mellitus is not closely related to the extent of vascular calcification, and this condition may be more strongly related to biochemical changes.The RANK/RANKL