Are you the owner of a lonely heart?

The US study found that men with fewer links with friends and family have higher levels of a protein known as IL-6 in their blood which can promote inflammation causing artery walls to thicken and harden. This can lead to heart attacks and strokes.

Eric Loucks, from Harvard School of Public Health in Boston, who took part in the research told the BBC: 'Our analyses suggest that it may be good for the heart to be connected. In general, it seems to be good for health to have close friends and family, to be connected to community groups or religious organisations, and to have a close partner.'

Cathy Ross, a cardiac nurse at the British Heart Foundation, said socially-isolated people may be more likely to smoke and take less exercise. 'Rehabilitation programmes and support groups, such as those run by the BHF, have been shown to support patients and their families, increase their confidence and reduce the incidence of isolation.'

The Framingham Heart Study involved 3267 men, with an average age of 62, who underwent physical examinations and answered a series of questions about their social lives, if they were single or married, how many friends and relatives they knew whom they could confide in and the extent of their participation in group activities and religious meetings or services.

The men were then given a social network score of one (for isolated) to four (for highly-connected). The result was a statistically significant difference in average levels of IL-6. Men with a score of one had 3.85 picograms per millilitre; men with a score of four 3.52 picograms. The same link was not found for women.

The research will be presented to a meeting of the American Heart Association.