New York, May 19 (IANS): Higher levels of bilirubin -- a natural antioxidant -- within the normal range in our blood may lower the rates of cardiovascular diseases (CVD) like heart failure, heart attack and stroke, finds a study.

A yellow-orange pigment, formed after breakdown of red blood cells and removed from our body by the liver, bilirubin has beneficial effects by acting as an antioxidant or interfering with atherosclerosis -- a condition where fats, cholesterol etc. accumulate on artery walls.

It acts as a natural defence and can prevent or limit the damage that occurs to blood vessels in individuals with arterial blockage.

According to the researchers from the Emory University in US' Georgia state, the antioxidant effect of bilirubin could be harnessed to reduce the chronic disease morbidity risk.

Higher levels of bilirubin meant lower risk of heart attack, heart failure or stroke, the study found.

People with the highest level of bilirubin had 76 per cent of the risk for combined cardiovascular events as the group with the lowest level, with effects seen even in people without liver disease.

The study, published in the Journal of the American Heart Association, was conducted on 100,000 participants, with an average of 48 years, including people with and without HIV infections

The study specifically looks at people living with HIV and at an anti-HIV drug, atazanavir, known to elevate bilirubin, but did not see an independent effect of atazanavir on cardiovascular risk.

Even if well-controlled by antiretroviral drugs, HIV infection has negative effects on cardiovascular health, said lead author Vincent Marconi, Professor at the varsity.