More than half of all cases of atrial fibrillation could be prevented if people took better care of themselves. That's the conclusion of a 17-year long study.

The study authors claim that this is just as true for other types of heart disease.

Atrial fibrillation (AF) is a disease where the heart beats erratically, causing it to pump blood inefficiently. This causes poorer circulation and raises the risk of heart attack and stroke. It's most common in elderly individuals. But it's not always a consequence of bodily aging.

The researchers also found racial and gender disparities in the prevalence of AF risk factors. More than 80% of African-Americans had one or more risk factors, compared to 60% of whites.

The study found that over half of all cases of AF were linked to specific risk factors — high blood pressure, diabetes, smoking and being overweight. By far, the strongest risk factor was high blood pressure, which accounted for more than one-fifth of all cases. Controlling blood pressure alone could cut the occurrence of atrial fibrillation by over 20%.

In the study, people with a low-risk profile were two-thirds less likely to develop AF than people with a high-risk profile. This suggests that if more people lowered their risk factors, there would be fewer cases of AF.

Yet only 5% of the people had this low-risk profile.

The study followed 14,598 middle-aged adults from four communities in Maryland, Minnesota, Mississippi and North Carolina. Their average age was 54. A total of 55% were female, 75% were white and 25% were African-American. The average time of follow-up was 17 years. During the study, 1,520 new cases of AF were diagnosed.

After an initial interview and medical exam, the participants were divided into three groups based on their risk factors for AF: high, medium or low. Only 5% fit into the low-risk group. More than 25% fell in the medium risk group and two-thirds fell in the high-risk group. People in the low-risk group had normal blood pressure and weight and did not smoke or have other heart disease or diabetes.

Nearly 57% of the new cases of AF could be explained by elevated risk factors, particularly high blood pressure.

The researchers also found racial and gender disparities in the prevalence of AF risk factors. More than 80% of African-Americans had one or more risk factors, compared to 60% of whites. Only 2% of African-American men and women had optimal risk factors, compared to 3% of white men and 10% of white women.

The researchers point out that these disparities show a special need for African-Americans to closely monitor and treat any high blood pressure or diabetes.

An article on the study was published online on March 28, 2011 by the journal Circulation. It will also appear in a future print issue of the journal.