Vitamin D deficiency is a common condition, present in approximately 30% to 50% of the general population. Low 25- hydroxyvitamin D levels may have an effect on cardiovascular health, cancer, and diabetes. Several studies found a relationship between the levels of the active form of vitamin D, blood pressure, and plasma renin activity.

Because the vitamin D receptor (VDR) is present in most cells, vitamin D has a wide range of therapeutic and health-related benefits. The active form of vitamin D3 is a steroid hormone shown to regulate more than 60 genes. The translocation of 1α,25(OH)2D3 into cells, where it binds with high affinity to vitamin D nuclear receptors, results in altering rates of gene expression. By this pathway, the active form of vitamin D influences a number of genes relevant to arterial wall functions. These include VEGF, matrix metalloproteinase, myosin, and structural proteins. Vitamin D receptors are densely distributed in the endothelium, and vitamin D3 modulates vascular tone by reducing calcium influx into the endothelial cells.

1,25(OH)2D is a very effective modulator of the immune system. In animal models, it has been demonstrated that pretreatment with 1,25(OH)2D is effective in preventing the onset of type 1 diabetes, multiple sclerosis, rheumatoid arthritis, and Crohn’s disease.

Our goal was to prove that optimal levels of vitamin D could be correlated with the increased number of circulating EPCs and angiogenic cells. The number of circulating EPCs in an individual’s blood may be an indicator of overall vascular health. In atherosclerosis, the endothelial layers may become damaged, and nearby endothelial cells are recruited to help repair vessels or form new ones. EPCs are generated from bone marrow and contribute to repair of the endothelium. A lack of EPCs can lead to vascular dysfunction and a progression of atherosclerosis. In a large population– based study it was shown that there was a positive relation between EPC numbers and vascular risk factors and a positive association of EPCs with Framingham risk factors.

Our focus was to evaluate if the population of EPCs could be correlated with vitamin D status.

According to our study, the difference between two groups of subjects with sufficient and insufficient or deficient levels of vitamin D was significant for cholesterol/HDL ratio, VLDL, triglycerides, and blood pressure. A level of vitamin D higher than borderline 40 ng/mL demonstrated a positive effect on blood pressure.

The mean percentage of EPCs for subjects with a level of vitamin D lower than 40 ng/mL was significantly different than the mean percentage of EPCs for subjects with a level of vitamin D higher than 40 ng/mL (0.045 versus 0.068, P value for trend <0.01). A positive correlation was found between CACs and the level of vitamin D.

To maximize health and reduce the risk of common diseases, it is important to pay attention to the 25(OH)D concentrations. Maintaining a healthy 25(OH)D concentration may be important to prevent coronary disease. According to our results, the minimum concentration of 25(OH)D should be 40 ng/mL; and for maximum bone health and prevention of many chronic diseases, the vitamin D concentration should be higher than 40 ng/mL.

The results of the study are published in journal: Vitamin D Concentrations, Endothelial Progenitor Cells, and Cardiovascular Risk Factors. Mikirova NA, Belcaro G, Jackson JA, Riordan NH. Panminerva Medica 2010, 52:(Suppl. 1 to No. 2).