Being a loner could be bad for your heart — if you are a man, at least. Men with few social connections have the highest levels of a blood marker for inflammation that has been linked to atherosclerosis, the blocking of the arteries.

Eric Loucks, of the Harvard School of Public Health in Boston, Massachusetts, said: “It seems to be good for health to have close friends and family, to be connected to community or religious organisations, and to have a close partner.”

His team studied 3,267 people as part of a 50-year monitoring of the population of Framingham, Massachusetts, which has yielded more than 1,000 scientific papers on heart and other diseases.

The average age of the participants was 62, and they had physical examinations. Their blood was measured for concentrations of four markers, including one called interleukin-6, or IL-6. People gave their marital status, numbers of relatives and close friends in whom they could confide, as well as information about involvement in religious meetings or clubs.

Men with the least social involvement had the highest levels of IL-6, although there was no such link for women, Dr Loucks said. There were no links between the other blood markers and social involvement.

Researchers have suggested that social isolation may influence “health behaviour”, such as smoking, which in turn affects IL-6 levels, or that isolated people are often depressed and stressed. — The Guardian