Insufficient vitamin D levels have previously been linked to an increased risk of heart disease, but now researchers say there’s a genetic variance that may explain it.

A new study published in the journal Pharmacogenomics has found that individuals with high blood pressure who possess a gene variant that affects an enzyme critical to normal vitamin D activation are twice as likely as those without the variant to have congestive heart failure.

"This study is the first indication of a genetic link between vitamin D action and heart disease," said study author Robert Simpson.

Researchers found that a variant in the CYP27B1 gene was associated with congestive heart failure in patients with hypertension. It is already known that mutations that inactivate this gene reduce the required conversion of vitamin D into an active hormone.

He added that further studies are needed to confirm their findings on a larger, more diverse group of patients.

In addition, the findings could result in new screening tests. "In the future, we may be able to screen earlier for those most vulnerable and slow the progress of the disease," said Simpson.

Besides promoting heart health, vitamin D is believed to be important in fighting diseases like diabetes, cancer and osteoporosis. It is available in nutritional supplement form as well as in dietary sources like dairy products, fish and fortified cereals.