Older adults who live alone are more likely to suffer a heart attack or die suddenly from cardiac arrest than those who live with a mate, a large study suggests.

Danish researchers found that of the more than 138,000 adults they followed for two years, singles had a higher risk of suffering an acute coronary syndrome (ACS) - either a heart attack, serious chest pain known as unstable angina, or sudden cardiac death.

Single women older than 50 and single men older than 60 were at particular risk, the researchers report in the Journal of Epidemiology and Community Health.

Whereas single women in that age group accounted for only 5 percent of the study group, they suffered more than one-third of all ACS deaths. Single men older than 60 constituted less than 8 percent of the study group, yet accounted for close to two-thirds of ACS deaths.

Though it’s not entirely clear why singles had greater heart risks, there are a number of reasons the association makes sense, according to the study authors, led by Dr. Kirsten M. Nielsen of Aarhus Sygehus University Hospital.

“I think it’s very much likely that there is an accumulation of risk factors among singles,” Nielsen told Reuters Health. These include smoking, obesity, high blood pressure, poor diet and lack of exercise - all of which, studies suggest, are more common among single adults.

People who live alone may also have a smaller social network, which research has linked to ill health effects, Nielsen and her colleagues note in their report.

Their findings are based on data for 138,290 adults ages 30 to 69, obtained from Danish public registers. Over two years, the researchers identified 646 people who suffered an acute coronary syndrome.

Overall, people living alone were at two to three times greater risk than adults who lived with a partner. In fact, single living and older age were the two strongest predictors of heart trouble among all the demographic factors the researchers studied - more important than education, occupation and income.

There was an exception, however; divorced women showed a reduced risk of ACS.

This is not necessarily synonymous with being single, as some of these women may have been living with someone. But it’s possible divorced women are a low-risk “subgroup” among singles, Nielsen said, perhaps due to healthier lifestyles.

She suggested that older adults who live alone take stock of their lifestyle habits and ask their doctors about ways to control any heart disease risk factors they may have.

SOURCE: Journal of Epidemiology and Community Health, August 2006.