VERONA, ITALY — Vitamin D3 deficiency was found to be highly prevalent in adults with type 2 diabetes, and was strongly and independently associated with early signs of atherosclerosis in a new study conducted in Italy.
The results are provocative and add to a growing body of evidence suggesting that serum concentrations of 25-hydroxyvitamin D3 may be inversely associated with cardiovascular disease, as well as with some cancers and metabolic syndrome.
Further follow-up and interventional studies are needed to determine whether hypovitaminosis D3 predicts the development of atherosclerosis in people with type 2 diabetes, and whether vitamin D3 supplementation would be protective against atherosclerosis, Dr. Giovanni Targher and colleagues reported in an award-winning poster at a joint meeting of the Italian Association of Clinical Endocrinologists and the American Association of Clinical Endocrinologists.
“These findings confirm some previous evidence demonstrating that vitamin D deficiency is highly prevalent in people with type 2 diabetes, and suggest that hypovitaminosis might be an underestimated, novel risk factor for cardiovascular disease among type 2 diabetic adults,” Dr. Targher said in an interview.
Using a chemiluminescence immunoassay, the investigators compared winter serum levels of 25-hydroxyvitamin D (25[OH]D3) in 390 consecutive patients with type 2 diabetes and 390 nondiabetic age- and gender-matched controls. Hypovitaminosis D3 was defined as a 25(OH)D3 level of 37.5 nmol/L or lower. Common carotid intimal medial thickening was measured using ultrasonography only in patients with diabetes by a single operator who was blinded to patient details.
Significantly more patients with diabetes had hypovitaminosis D3, compared with controls (33.3% vs. 16.4%), reported the authors, who are with the division of internal medicine, Sacro Cuore Hospital of Negrar (Italy). In addition, the 130 patients with diabetes and hypovitaminosis D3 had a significant increase in carotid intimal medial thickening, compared with the 260 vitamin D-sufficient diabetics (1.10 mm vs. 0.87 mm, respectively).
Compared with vitamin D-sufficient counterparts, diabetic patients with hypovitaminosis D3 were also slightly older (59 years vs. 57 years) and had significantly higher hemoglobin A1c (7.5% vs. 7.2%), fibrinogen (4.7 g/L vs. 4.3 g/L) and high-sensitivity C-reactive protein (5.0 mg/L vs. 4.3 mg/L) concentrations. Sex; body mass index; blood pressure; lipids; calcium; estimated glomerular filtration rate; diabetes duration and treatment; smoking history; and statin therapy were not significantly different between the groups of diabetic patients.
“Because a lack of vitamin D can negatively affect bone health and have other nonskeletal adverse effects on several organ systems, a widespread screening for vitamin D deficiency or routine vitamin D supplementation should be seriously considered for people with diabetes,” Dr. Targher said.