Targeting people with high levels of homocysteine in their blood for treatment with vitamin supplements may be a cost-effective way to reduce the risk of heart disease, according to a new study.

Researchers say that high homocysteine levels may be associated with up to 6% to 10% of all heart-related deaths in the US. Homocysteine is found everywhere in the body. Studies have shown that it can harm the lining of blood vessels and create an environment in which blood clots more easily, creating a risk factor for clogged arteries and heart disease.

It is unclear whether lowering homocysteine levels can reduce the risk of heart disease but there is some evidence that homocysteine levels can be lowered with folic acid and vitamin B12 supplements.

"It is better to screen patients who are at-risk and treat those with elevated levels of homocysteine as opposed to treating everyone empirically," says lead author Brahmajee Nallamothu, MD, MPH, a cardiology fellow at the University of Michigan in Ann Arbor, Michigan. "The strategy to screen and treat is more cost-effective than that of treating everyone."

Researchers constructed a decision analysis model to estimate how much risk reduction was needed for the strategies to be cost-effective. They simulated groups of 40-year-old men and 50-year-old women in the general population. Researchers looked at costs and benefits to make sure that all at-risk people, or those known to have high homocysteine levels, got enough folic acid (400 micrograms) and vitamin B12 (500 micrograms). Researchers found that homocysteine lowering reduced the relative risk of heart disease by 11% in men and 23% in women.

Researchers say that despite the cost of blood tests to screen people with high homocysteine levels, this strategy would cost 60% less in the long run, since vitamins would be targeted at those who could most benefit from reducing homocysteine levels. "It would be a reasonable strategy based on the data we have today," says Nallamothu.

In 1997, the US Food and Drug Administration mandated a moderate level of folic acid fortification in all grain products including pasta, cereal, and bread. Now, all the enriched grain products on the market contain 400 micrograms of folic acid. Most multivitamin supplements also contain both nutrients, as do whole-grain products, oranges, and green vegetables.

Godfrey Oakley, MD, MSPM, a visiting professor in the Department of Epidemiology at the Rollins School of Public Health at Emory University in Atlanta, Georgia, says that the study reiterates the benefit of taking sufficient folic acid and vitamin B12. One of the key issues is fortification with folic acid and vitamin B12 in all grain products, so that everyone is affected.

"Homocysteine levels need to be reduced through fortification," Oakley emphasizes. "Right now, there is folic acid [in the grain products], there are clearly needs to be more B12 added . . . If that gets done, you probably wouldn't need to do either one of these two strategies."

Oakley says the study only compared treating everyone with vitamins or screening for homocysteine and then treating with vitamins. But he argues that higher levels of folic acid and B12 fortification in grain products may also be a viable option, provided the products reaches the entire population.

"You don't have to screen anybody and you don't have to give them a pill," says.Oakley. "It's a very good idea to lower the homocysteine if people start eating products containing folic acid, or taking a multivitamin supplement per day."

The study is published in the Dec. 11 issue of the Archives of Internal Medicine.