Diabetes is an independent risk factor for heart disease. And the adverse effect of diabetes extends to all parts of the cardiovascular system. New research suggests that low levels of vitamin D in people with diabetes may be the cause of one type of heart disease — atherosclerosis, or hardening of the arteries.
“About 26 million Americans now have type 2 diabetes. And as obesity rates rise, we expect even more people will develop diabetes. Those patients are more likely to experience heart problems due to an increase in vascular inflammation so we have been investigating why this occurs,” according to Carlos Bernal-Mizrachi.
We took everything into account. We looked at blood pressure, cholesterol, diabetes control, body weight, and race. But only vitamin D levels correlated to whether these cells stuck to the blood vessel wall.
In an earlier study Dr. Bernal-Mizrachi and his colleagues found that vitamin D appears to play a significant role in heart disease. The current study takes their work a step further by suggesting that vitamin D deficiency in patients with diabetes allows a certain type of cells called macrophages to stick to cells in the walls of blood vessels near the heart and trap cholesterol, causing blockage in those vessels.
For the current study, researchers studied the vitamin D levels of 68 people. Forty-three people had type 2 diabetes. The other 25 individuals were similar in age, sex, and weight but did not have diabetes. In patients with diabetes who had low levels of vitamin D (defined as less than 30 ng/mL), macrophage cells tended to stick to the walls of blood vessels. Over time this can lead to an accumulation of cholesterol, eventual hardening of the arteries, and the possibility of obstructed blood flow.
“We took everything into account,” said Amy E. Riek, MD, co-author of the study. “We looked at blood pressure, cholesterol, diabetes control, body weight, and race. But only vitamin D levels correlated to whether these cells stuck to the blood vessel wall.”
The researchers don’t yet know if supplementing with vitamin D will lessen the risk of developing atherosclerosis in patients with diabetes. They are now using mice to study whether vitamin D can prevent monocytes from sticking to the walls of arteries, and they are conducting two clinical trials with patients.
The study was published in the Journal of Biological Chemistry.