London: New research reveals that the risk of heart attack and stroke increases as a result of winter infections.

The joint study sponsored by the British Heart Foundation, the Medical Research Council and the Wellcome Trust discovered thatbronchitis can increase the risk of a heart attack by five times.The risk of having a stroke also trebles within the first few days of falling ill, according to researchers.

They found that the increased danger was caused not just by chest illnesses but other infections such as cystitis.

They believe inflammation may have something to do with it – either by helping to form the plaques that block arteries or by contributing to their rupture and causing heart attacks or strokes.

Around 300,000 people have heart attacks in Britain each year, 117,000 of them fatal. Every year more than 130,000 people in England and Wales suffer a stroke.

The latest study, published today in the New England Journal of Medicine, confirms that common infections play a part in triggering acute heart and circulatory problems.

The researchers examined the medical records of more than 40,000 people and discovered that the risk of heart attack was five times higher than normal in the first three days after a respiratory tract infection such as bronchitis or pneumonia.

The risk of stroke was found to be three times higher during the same period. The same applied to urinary tract infections such as cystitis.

However, in the following weeks after illness the risk of having a heart attack or stroke gradually decreased.
Professor Patrick Vallance, a researcher on the project at University College London, said: ‘The work shows that the timing of a heart attack is not random.’

He said the finding was important because it showed showed a surge in risk following a range of infections – not just chest infections, as might be expected.

Dr Liam Smeeth from the MRC, lead researcher on the project, said ‘This knowledge will open up new avenues for research and discovery.

‘Armed with the information we have found, we can begin to develop new strategies to reduce the occurrence of heart attacks and strokes.’

The BHF advised people to protect their hearts this winter by staying warm, eating a good diet, having a flu jab and being alert for unusual symptoms.

The researchers also investigated whether vaccinations, including flu and tetanus jabs, increased the risk of heart attacks or strokes. They found no increased risk associated with the vaccines, confirming their safety record.