But when these at-risk patients, who have the 2-2 form of haptoglobin, take 400 international units of vitamin E daily, they reduce their risk of heart attack by 43 percent, and their risk of dying of heart disease by 55 percent.

About 40 percent of diabetics have the 2-2 form of haptoglobin, while the rest have the 1 -1 or 2-1 forms. When they took the same vitamin E supplements, they did not show any significant reduction of cardiovascular risk resulting from vitamin E therapy.

The researchers had earlier demonstrated that haptoglobin 2-2 is predictive of heart disease, but only in people with diabetes. That's because diabetics tend to have more free radicals that destroy antioxidants. Furthermore, haptoglobin 2-2 is a very poor antioxidant when compared to the other haptoglobin types.

This combination means that diabetics with haptoglobin 2-2 have an even greater deficiency of antioxidants than do diabetics with the other haptoglobin variants. Therefore, an increased supply of antioxidants, such as those found in vitamin E, would be expected to provide the greatest benefit for these patients.

"If this larger study confirms our findings, the public health implications will be huge. Vitamin E would represent an inexpensive and safe way to reduce the risk of cardiovascular death and heart attack in a significant proportion of diabetic patients," the researchers wrote in their study.