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Strong community and social networks may do an ailing heart good, new study finds
High levels of 'social capital' in communities linked to reduced occurrence of acute coronary syndrome

| 27 February 2008

Home may be where the heart is, but it could be one's surrounding community that helps keep the ticker healthy, according to a new study led by researchers at the School of Public Health.

Specifically, the study found, low-income patients with existing heart problems are significantly less likely to have another heart attack or a recurrence of chest pain if they live in a county with higher measures of trust, cooperation, and social networks - something researchers call "social capital." This was true even after researchers accounted for such factors as gender, age, race, or ethnicity, and the existence of other concurrent health problems.

"This analysis points to a real effect on real people," says study lead author Richard Scheffler, professor of health economics and public policy. "It speaks to the value of clubs and social organizations in providing health information and reducing stress, both of which are known to reduce heart disease." Among the kinds of membership organizations the authors cite as potential channels of health information, for example, are labor unions, church groups, business or trade groups, veterans' groups, hospital or medical-service groups, service or fraternity groups, and youth groups.

"This is the first study to demonstrate a link between community social capital and prognosis following heart disease," says study co-author Ichiro Kawachi, professor of social epidemiology in the Department of Society, Development, and Human Health at the Harvard School of Public Health. "Other research has linked social capital to health outcomes, but most of these studies have been cross-sectional, and therefore difficult to draw conclusions about cause-and-effect relationships. The findings of this study take us in the right direction."

The researchers based the degree of social capital in any county upon the number of people employed in various organizations, including religious, civic, political, social, and alumni groups. They note that an organization's staff size correlates with its membership size, which in turn is a good indicator of the number of resources in a community.

There is growing evidence that cardiovascular health is linked to where a person lives, but it had been unclear whether location served as a proxy for other unmeasured factors, including the type of medical treatment or health care available there.

To address this gap, Berkeley researchers partnered with Kaiser Permanente Northern California, a nonprofit integrated health-care-delivery system.

Data was obtained from actual clinical records of nearly 35,000 Kaiser Permanente patients who had been hospitalized for acute coronary syndrome - a term describing symptoms of decreased blood flow to the heart - in Northern California between 1998 and 2002. Patients were tracked for symptoms of recurring heart problems. To protect patient privacy, only authorized Kaiser Permanente personnel had direct access to the clinical records for this study.

"Because we're using actual clinical records instead of self-reported medical information, we have a clearer picture of a person's health status and medical treatment," says Scheffler, who is also director of the Nicholas C. Petris Center on Health Care Markets and Consumer Welfare at the School of Public Health. "And because all the patients are in the same health- care system, we avoid the problem of comparing people with different kinds of health plans or who don't have insurance at all. We also were able to follow patients over time to track any recurrence of heart problems, which is very unique."

The authors note that patients in low-income areas have the most to gain from higher social capital.

"Our findings are consistent with the hypothesis that social capital is more helpful to those in the lower socioeconomic spectrum," says study co-author Carlos Iribarren, research scientist at Kaiser Permanente Northern California. "Those with greater economic advantage don't seem to benefit, or benefit less, because they have other resources available to them." 

Study co-author Timothy Brown, an assistant adjunct professor of health economics at Berkeley, adds: "While higher-income individuals can pay significant prices for social support in the private market - by joining country clubs, for example - lower-income people must depend on what is available in the community."

No membership required

The researchers point out that patients did not need to be members of any of the community organizations measured in order to benefit.

"An area with a high density of social networks and resources changes the character of a community, regardless of whether any one particular individual joins or not," says Scheffler. "It's the opposite of having a liquor store on every corner. You don't have to shop at the liquor stores to be impacted by the type of environment they create."

Thirty-five of California's 58 counties were included in the study. The eight counties found to have the highest levels of community social capital are, in descending order, San Francisco, Lake, Sacramento, Santa Cruz, Marin, Tuolumne, Nevada, and Alameda.

The full study, "Community-level social capital and recurrence of acute coronary syndrome," is to be published online in the Feb. 28 issue of the journal Social Science & Medicine. Other co-authors are Leonard Syme, a Berkeley professor emeritus of epidemiology, and Irina Tolstykh, research scientist at Kaiser Permanente Northern California. The project was jointly sponsored by Berkeley's Petris Center and the U.S. Centers for Disease Control and Prevention through the Center for Family and Community Health at the School of Public Health.