Vitamin D May Be Linked to Cardiovascular Structure Function

NEW ORLEANS, LA—Addressing vitamin D deficiency may improve cardiovascular health, according to data presented at ACC.11, the American College of Cardiology's 60th Annual Scientific Session.

Approximately 30–70% of the U.S. population is vitamin D deficient as a result of sun avoidance, increased prevalence of obesity and diabetes, a greater number of people with darker skin, an aging population, and a diet low in the nutrient, said John Lee, MD. According to the NHANES survey, only 10% of the U.S. population, primarily outdoor workers, meet the target blood level of vitamin D. Vitamin D deficiency is particularly common in hospitalized patients (57%), young adults (32%), and adolescents (24%). Significantly, 80% of blacks and 90% of individuals in nursing homes were found to be deficient. Dr. Lee stratified vitamin D levels as follows: severe deficiency (≤10ng/mL); deficiency (10–20ng/mL); mild to moderate deficiency (20–30ng/mL); sufficient (≥30ng/dL); ideal (40–60ng/mL); and toxicity (>150ng/mL).

James H. O'Keefe, Jr., MD states that he recommends patients with the following conditions be screened for vitamin D deficiency: darker skin, age >50 years, musculoskeletal disease, hypertension, cardiovascular disease, heart failure, hospital or healthcare settings, infections or autoimmune diseases, obesity or diabetes, indoor lifestyle or sun avoidance, neurodegenerative diseases, and kidney disease.

Vitamin D and Cardiovascular Health

“Since the epidemiology of vitamin D deficiency is similar to that of cardiovascular disease, the vitamin D axis may affect cardiovascular physiology,” said J. Brent Muhlestein, MD, of the Intermountain Medical Center, Murray, Utah. In the NHANES-III study, vitamin D status was found to be associated inversely with blood pressure in a large sample representative of the U.S. population. The study followed 12,644 adults and assessed 25-hydroxyvitamin D test or 25 (OH)D levels. When divided into 25(OH)D quintiles, mean systolic blood pressure was 3 ± 0.7mmHg lower for patients in the highest quintile compared with the lowest quintile, adjusting for age, sex, ethnicity, and physical activity (P<0.0004).

The Intermountain Healthcare cohort study found that vitamin D deficiency to be very common among patients with cardiovascular disease. Researchers compared 27,686 patients ≥50 years with cardiovascular disease. It was observed that in patients with vitamin D levels ≤15ng/mL, 25.1% of patients had coronary artery disease, 19.2% had heart failure, 11.8% had atrial fibrillation, and 6.3% had peripheral vascular disease.

According to Dr. Muhlestein, the VITAL study will continue to study the effects of vitamin D3 in a patient population of 20,000 (males ≥60 years and females ≥65 years). The study plans to randomize patients who have no history of heart disease or cancer and who are not taking vitamin D (>800IU/day) or calcium (>1,200mg/day), to vitamin D3 2,000IU/day or placebo. “Observational evidence supports the use of vitamin D supplementation in deficient patients to reduce cardiovascular risk,” concluded Dr. Muhlestein.

In addition, experimental vitamin D deficiency has been shown to result in abnormalities in cardiac structure and function, according to Thomas J. Wang, MD from Massachusetts General Hospital, Boston, MA. “Vitamin D supplementation normalizes myocardial dysfunction in animal models. In humans, there are observational data and pilot studies, but no definitive RCTs yet,” he concluded.

Evidence for an association with nonskeletal outcomes is not yet sufficient to inform dietary recommendations, according to Joann Elisabeth Manson, MD, DrPH of Brigham and Women's Hospital, Boston, MA. It remains unclear whether vitamin D deficiency is a primary cause of cardiovascular disease or whether a number of independent factors are the cause.

“There is good biological evidence linking vitamin D with cardiovascular structure function, but it remains unclear whether or not vitamin D should be recommended as a supplement as often as vitamins C and E. Further large-scale studies are needed to confirm the results,” Dr. Manson concluded.