Relationships that foster a sense of belonging and intimacy seem to play a vital role in maintaining health or surviving serious illnesses. Conversely, social isolation tends to increase risk for mortality from a number of causes. These findings -- which add to mounting scientific evidence that behavioral, social, and biological factors often interact to affect health or illness -- emerge from a review of population-based, mortality-risk research published in the last two decades.

Lisa F. Berkman, Ph.D., Professor of Epidemiology and Chair of the Department of Health and Social Behavior, at the Harvard School of Public Health, discussed her findings on Thursday, May 29, from 10 - 11 a.m., in Wilson Hall, Building One, at the National Institutes of Health (NIH), Bethesda, Maryland. This lecture was part of the monthly series organized by the Behavioral and Social Sciences Research Coordinating Committee, under the sponsorship of the NIH Office of Behavioral and Social Sciences Research.

"The extent to which we maintain close personal relationships, and the degree to which we feel a part of our community or have deep, abiding social and psychological resources help to determine how protected we are against biological, environmental, or interpersonal assaults," Dr. Berkman says.

In the studies published between 1976 to 1994 that Dr. Berkman examined, researchers measured the quality of social attachments and related it to a broad range of illnesses, from ischemic heart disease, cancer, and cerebrovascular and circulatory disease, to respiratory diseases, gastrointestinal conditions, and other potential causes of death. "These studies showed that in almost all cases, those individuals who were the most socially isolated and disconnected were clearly at increased risk of developing illnesses that led to death."

As to how social experience can get "inside the body," findings of several of the studies Dr. Berkman reviewed suggested that multiple biologic pathways are involved, two of which may be the immune and neuroendocrine systems. In one of the studies that focused on cardiovascular reactivity, which the neuroendocrine system affects, study volunteers completed two laboratory tasks. Fifty percent of the subjects worked alone, the other half had a friend or "supportive partner" accompany them. Those in the latter group showed beneficially reduced heart rate and blood pressure. The researchers suggested the "friend's presence may have acted as a conditioned stimulus or a ‘safety signal,' altering neural input to the heart during challenge."

While Dr. Berkman expects that future studies will continue to confirm the relationship between social ties and health status, a lot remains unknown about how these factors interact. For example, "where along the spectrum of disease development do social factors have their greatest impact; what are the mechanisms or pathways that link socioenvironmental conditions to morbidity and mortality rates; and of utmost importance, can we modify or intervene on these conditions to improve health status?"

In addressing the issue of intervention, Dr. Berkman points out that since macrosocial, economic, and welfare policies influence the ability of families and communities to maintain high levels of social integration and support, larger-scale interventions aimed at communities or work sites may be one way of making significant contributions to strengthening social ties.

"To improve health among vulnerable and high-risk populations, we will need to focus on preventive efforts that, at their core, promote social support and develop family and community strengths," Dr. Berkman says. "Acknowledging that health promotion rests on the shoulders not only of individuals, but also of their families and communities, means that we must commit resources over the next decade to designing, testing, and implementing interventions in this area." This, she says, "is a crucial next step."