New risk factor for heart disease identified

Physicians can now identify overweight people at very high risk of developing heart disease, thanks to research published this week in BMC Cardiovascular Disorders. People who suffer from heart disease are more likely to produce smaller versions of a protein called apolipoprotein(a).

Being overweight increases your risk of suffering from heart disease. However other factors, such as having high levels of low-density lipoprotein in the blood, also play a role. Now it seems that the size of apolipoprotein(a), the protein component of low-density lipoprotein(a), may also affect your risk. Apolipoprotein(a) comes in numerous different sizes, the largest of which has a molecular weight almost three times as great as the smallest.

A group of researchers, led by Diego Geroldi, took blood samples from 715 outpatients at the IRCCS San Matteo Hospital, Italy. These volunteers were then split into four groups depending on whether or not they suffered from heart disease, and whether or not they were clinically overweight.

By analysing the samples, the researchers discovered that overweight people suffering from heart disease were more likely to produce a version of apolipoprotein(a) with a low molecular weight than overweight people with no history of heart disease.

The researchers write: “The presence of at least one low molecular weight version of apolipoprotein(a) is a reliable way of discriminating between overweight subjects with a high risk of heart disease and those without”.

The researchers believe that by analysing apolipoprotein(a), physicians could calculate the overall risk of heart disease to people that are overweight. This assessment could then lead to “more intensive treatment of modifiable cardiovascular risk factors”, such as smoking, blood pressure, weight, diet and exercise.

Volunteers of normal weight who suffered from heart disease were also more likely to produce low-molecular weight versions of apolipoprotein(a) than those with no history of heart disease. However, high blood pressure or smoking were more reliable ways of identifying those at high risk of heart disease in this group.

Apolipoprotein(a) is thought to interfere with the destruction of a protein called fibrin which is involved in the development of atherosclerosis and thrombosis. Both these diseases come under the umbrella of ’heart disease’. Perhaps the smaller versions of apolipoprotein(a) promote these conditions more than the larger versions.

This release is based on the following article:

Relationship between apolipoprotein(a) size polymorphism and coronary heart disease in overweight subjects Enzo Emanuele, Emmanouil Peros. Piercarlo Minoretti, Columba Falcone, Angela D’Angelo, Lorenza Montagna and Diego Geroldi BMC Cardiovascular Disorders 2003, 3:12

Upon publication, this article will be available free of charge, according to BioMed Central’s Open Access policy at: http://www.biomedcentral.com/1471-2261/3/12/abstract