Association of 25 hydroxyvitamin D levels with glycation biomarkers insulin resistance and syntax score in type 2 diabetes with coronary artery disease

Abstract

Vitamin D, a prohormone, is known for its importance in skeletal health. The vitamin D receptor (VDR) is expressed in multiple cells and various organs in the body, including the brain, heart, skin, prostate, breast, and gut. Vitamin D deficiency (VDD) is widely prevalent despite plentiful sunshine even in tropical countries such as India. VDD is associated with the incidence of various chronic ailments including obesity, insulin resistance (IR), diabetes, cardiovascular disease (CVD), and cancer. Coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) are rapidly increasing in India, causing nearly 5.8 million deaths per year. T2DM is an established risk factor for CAD. Vitamin D can directly enhance synthesis and release of insulin from pancreatic and#946;-cells as well as increase the expression of the insulin receptor in peripheral tissues. Prolonged hyperglycaemia results in non-enzymatic glycation of proteins, lipids, and nucleic acids, leading to the formation of advanced glycation end products (AGEs). In vitro studies show that deleterious effects of AGEmodified albumin on endothelial cells could be prevented by coincubation with calcitriol, the active form of vitamin D. The current study aimed at finding the association of 25- hydroxyvitamin D (25(OH)vitamin D) with CAD risk factors, glycation biomarkers, insulin resistance (IR), and angiographic findings among T2DM with CAD. The study was carried out among T2DM patients with CAD with significant angiographic findings (n=130), aged 35-65 y, of either gender. The participants were recruited based on the inclusion and exclusion criteria after obtaining ethical clearance from institutional ethics committee. Blood samples were collected in the fasting state for the estimation of 25(OH)vitamin D, fasting glucose, fasting insulin, AGE and sRAGE. Estimated 25(OH)vitamin D (CLIA), insulin (CLIA) and glucose (GOD-POD) on autoanalyser Vitros 5600. Insulin resistance was calculated by HOMA- IR method. AGE and sRAGE were estimated by commercially available ELISA