A simple blood test could warn people whether they are likely to suffer a heart attack within five years, scientists believe.

Researchers have discovered that high levels of antibodies – molecules produced by the immune system – are linked to a low risk of heart problems, regardless of other risk factors.

Currently doctors use information such as age, sex, medical history, cholesterol levels and blood pressure to calculate the risk of future heart problems.

But the new test looks for levels of protective IgG antibodies which seem to shield the body from a heart attack even when cholesterol and blood pressure is high.

People with the highest number of antibodies had a 58 per cent lower risk of coronary heart disease or heart attack and a 38 per cent lower chance of suffering a stroke or other heart events during the five year trial period.

“Linking a stronger, more robust immune system to protection from heart attacks is a really exciting finding,” said lead researcher Dr Ramzi Khamis, consultant cardiologist at the National Heart and Lung Institute, Imperial College London.

“As well as improving the way we tell who is at the highest risk of a heart attack so that we can give them appropriate treatments, we now have a new avenue to follow in future work.