Too little vitamin D might be a contributing factor.

Vitamin D deficiency has been shown to lead to cardiovascular problems in mice. Might that occur in people as well?

THIS STUDY analyzed data on 1,739 men and women (average age, 59) without cardiovascular disease. About 40 percent had high blood pressure. In a five-year period, 120 people developed a heart-related problem such as heart attack, stroke, angina or heart failure. Based on blood tests, people moderately deficient in vitamin D (less than 15 nanograms per milliliter) were 62 percent more likely to have had heart trouble than were those with higher vitamin D levels (levels of 30 ng/mL and higher are considered optimal for bone health). If they also had high blood pressure, their risk increased to twice that of others. Overall, the greater the vitamin deficiency, the higher the risk of heart problems.

WHO MAY BE AFFECTED? People with vitamin D deficiency, which affects an estimated third to half of otherwise healthy people of middle age and older. Food sources of vitamin D include milk, fortified cereal, salmon, mackerel, sardines and tuna. Sunshine is another source; the vitamin is made by the body after exposure to ultraviolet rays.

CAVEATS Whether vitamin D supplements might help prevent cardiovascular disease was not tested. All participants were white; results may differ in nonwhite populations.

FIND THIS STUDY Jan. 7 online issue of Circulation (click “Publish Ahead of Print”).

LEARN MORE ABOUT vitamin D at http:ods.od.nih.gov/factsheets. Learn about heart disease at www.cdc.gov.

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment’s effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.