The research, jointly carried out by researchers at the University of Leicester and the University of Leeds, in collaboration with colleagues in Germany at the Universities of Lubeck and Regensburg, takes scientists a step closer to understanding of how the genetic make-up of body can cause an individual to develop heart disease, and to predicting people at most risk.
The researchers picked the first important clues to the identities of these variants from a genome-wide analysis conducted in almost 2,000 people with coronary artery disease and 3,000 healthy controls as part of the Wellcome Trust Case Control Consortium (WTCCC), the largest ever study of the genetics of common disease.
Upon comparing the findings with the German MI Family Study, with almost 900 addition cases and 1600 additional controls, the researchers found that changes in the DNA on chromosomes 2, 6, 10 and 15 and two on chromosome 1 were associated with increased risk of developing coronary artery disease and heart attacks.
The study also confirmed the importance of a variant on chromosome 9, previous identified in an independent study.
"We are not talking about rare genetic variants here, but rather variants that are very common in our population," New England Journal of Medicine quoted Professor Nilesh Samani, British Heart Foundation Chair of Cardiology at the University of Leicester and lead author on the paper, as saying.
"Many of these genetic variants are carried by between a quarter and three-quarters of white Europeans. They are clearly very important and explain a significant proportion of the heart attacks that occur," he added.
Carrying one copy of the newly identified variants increases the chances of developing heart disease by at least 20 per cent, while carrying two such copies increases the risk by over 40 per cent, say researchers. An individual carrying copies of more than one of the genetic variants may be at a substantially higher risk, they add.
"Understanding the genetics that lead to heart disease is a powerful tool to tell us how much risk a person faces," says Professor Samani.
"However, it's important to emphasise that even if a person carries one or more of the risk variants, they can still do a lot to reduce their risk by adopting a healthy lifestyle, not smoking and if they have high blood pressure or raised cholesterol levels, to have these treated," he adds.
The researchers say that though some of the variants implicated are involved in cell growth and cell division, further studies are being planned to understand exactly how this leads to heart disease.
"We still don't know the whole story, but these findings are an important step along the way to understanding what causes heart disease," says Professor Alistair Hall from the University of Leeds, also a co-author of the study.
"Heart disease is a complex disease, involving a number of genetic variants, many which until now had not been thought to be implicated in heart disease," adds Professor Hall.