Sibling history predicted heart disease risk better than parental history or traditional risk factors, a Johns Hopkins University team found.

This could help identify which individuals should do most to reduce their heart risk, say the authors.

Their findings, based on nearly 8,500 people, appear in Circulation.

Brothers and sisters

It is well known that things like smoking, high cholesterol and having a parent who suffered a heart attack at a young age all increase a person's risk of heart disease significantly.

But it was not known how important heart disease in a sibling might be as a risk factor.

This is very original and exciting. It makes sense. Professor Alistair Hall, British Heart Foundation professor

Cardiologist Roger Blumenthal and colleagues scanned the arteries of 8,549 people with no obvious signs or symptoms of heart disease.

This was to look for signs of plaque build up inside the vessel walls, called atherosclerosis, which is an early sign of cardiovascular disease.

The volunteers were then asked about any risk factors for heart disease, such as smoking, blood pressure and whether any of their relatives had had a heart attack or surgery for heart disease by the age of 55.

The volunteers were two-and-a-half- to three-times more likely to have a higher degree of furring of their arteries if a brother or sister had already been diagnosed with heart disease.

Screening

This was much more than the risk posed by a parent with heart disease.

Dr Blumenthal said this knowledge could help screen for people at greatest risk of developing heart disease.

"The overall long-term goal is to use these findings to develop faster and better means of identifying early atherosclerosis in high risk groups and prevent its progression to full blown heart disease," he said.

Professor Alistair Hall, consultant cardiologist at Leeds University and British Heart Foundation professor who has carried out research into family patterns of heart disease, said: "This is very original and exciting. It makes sense.

"A brother and sister will share 50% of their genes by chance and so will a child and a parent.

"You would expect the predictive value to be the same, but I guess the difference is the era in which the parents will have lived through versus the sibling.

"Siblings will have been exposed to similar environmental risks so it does not surprise me that they are a more accurate predictor of risk."

He said doctors were beginning to realise that it is important to ask patients about siblings' history of heart disease.