Size And Strength Of Social Networks Influence Heart Disease Risk

February 16, 2005

GAINESVILLE, Fla. — Weight, cholesterol and blood pressure aside, women might be wise to factor in yet another barometer of heart health: the size and strength of their social circle.

Casting a wide net when it comes to friends and family appears to be associated with a dramatically lower risk of suffering a heart attack or stroke, landing in the hospital or dying from heart disease, reports a national team of researchers from the University of Florida and seven other institutions that studied 503 women with chest discomfort. In contrast, women who did not have strong relationships with others were more than twice as likely to die as their more sociable counterparts in the study, described in the journal Psychosomatic Medicine.

The findings, gleaned from the Women’s Ischemia Syndrome Evaluation, build on more than 30 years of medical research that reinforces the relationship between the mind and major illness, including cancer, dementia and viral infections. Scientists know that married men and women live longer, and they theorize that larger social networks lessen disease risk by reducing negative health habits such as smoking, by boosting immune system responses and by yielding socioeconomic benefits and greater social support to offset emotional distress associated with illness.

The National Heart, Lung and Blood Institute-funded study, however, is among the first to link social isolation to increased risk of death in women with suspected heart disease.

“It’s important to recognize that for centuries there has been a group that believes there’s a strong interaction between the mind and the heart, though the exact relationships are not clear,” said Carl J. Pepine, M.D., chief of cardiovascular medicine at UF’s College of Medicine. “In my view, the No. 1 take-home message is that if you’re a woman with chest discomfort, have a lot of friends.”

Marriage proved beneficial for women in the study, but simply having one or two casual friends also was associated with better health outcomes, Pepine said. The larger the social circle, however, the healthier the women were.

“This does not have to be a complicated social network; this can be an intense relationship with one or two other close friends or significant others,” he said. “Many times these social networks are developed in church groups, in work groups, in recreational groups. All of these can be very helpful, so one ought to encourage the development of social support among patients with coronary disease.”

Study participants had signs characteristic of coronary artery disease, such as chest discomfort, and underwent a battery of tests — including coronary angiography — to assess whether they had blocked arteries. Most did not have severe heart disease, but many did suffer from depression or other forms of psychological distress. They also completed standardized questionnaires designed to quantify how many friends they had and, over a two-week period, the amount of contact they had with coworkers and family and how frequently they engaged in social and recreational activities. Researchers then tracked their health for two to four years.

About half the women studied reported having smaller social networks — fewer than six relationships with friends or family. Compared with women who had larger social circles, they were far more likely to have a higher number of heart disease risk factors that were more severe, including arterial obstructions and underlying heart disease detectable with angiography. Researchers also found that women with smaller social networks tended to weigh more and had higher rates of smoking, diabetes, high blood pressure and depression — and were 2.4 times more likely to die. Of the women studied, 30 died during the follow-up period. Low income and heart disease risk also were associated, particularly for women earning under $20,000 a year.

“Women who had annual incomes less than that were in the lowest part of the distribution of the social network and, therefore, in the highest risk categories for mortality,” Pepine said. “These findings would suggest that strong social support networks are very important in modifying the risk from coronary heart disease.”

It’s not yet fully understood what it is about a social relationship that benefits health, said Thomas Rutledge, Ph.D., an assistant professor of psychiatry at the University of California, San Diego, and the study’s lead author.

“There have been a lot of hypotheses,” Rutledge said. “Some of these theories include things like socioeconomic factors, that, for example, people who are worse off physically and financially tend to be more socially isolated. That involves things like being able to afford a bus pass so they are relatively tied close to home. They can’t afford to be involved and participate in different types of activities or go out to lunch with friends — the kind of basic things that promote social relationships. And having people around if you are sick makes a big difference. If you’re at home and you’re alone and you don’t have a husband and you don’t have friends nearby and you have a heart attack or a stroke, isn’t your risk of dying much greater than if someone’s in the home or close by to help you get to the hospital? Probably so.”

Ultimately, the results reinforce the importance of evaluating psychological and social characteristics among women at risk for heart disease, Pepine said. Physicians could have their patients complete the standardized checklists used in the study to evaluate their social networks and then profile their risk “much the same way we would draw blood to measure their cholesterol or take their blood pressure or measure their weight,” he said.

People living with serious and chronic medical conditions such as diabetes or high blood pressure often tend to become more isolated socially and start to withdraw, Rutledge said.

“They may need extra encouragement from some of their health-care providers,” he said. “Even though certain people differ in the amount of social contact they need, most people do seem to benefit not only psychologically but also in terms of physical health from having some degree of social involvement. While you can’t go down to a store and buy a friend, physicians or psychologists can certainly recommend this is something a person can do to improve their health and their quality of life.”

Most people tend to think of disease as purely a medical or biological process, said Willem Kop, Ph.D., an associate professor of medical and clinical psychology at Uniformed Services University of the Health Sciences in Bethesda, Md.

“It’s actually been known for a long time that health behaviors such as smoking and being overweight but also psychological factors such as depression and social isolation affect a range of diseases, including coronary disease,” Kop said. “So it’s important to look at this. But not everyone is equally helped by a large social network. To some people, friends and social interactions are not a relief, but rather stressful. What this study raises as an important question is whether there are psychological and environmental characteristics that make people more prone to be socially isolated. It is possible that these characteristics are a common factor in both social isolation as well as adverse cardiovascular risk.”