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Social networks and health: A life course perspective integrating observational and experimental evidence

Over the last several decades, there has been a great deal of observational evidence revealing the importance of social networks and the support they often provide in shaping health outcomes from the onset of disease to functioning and mortality. Based on that evidence, there have been several randomized trials aimed at reducing social isolation, changing network structure and improving social support. These interventions most often have had weak or null effects on the health outcomes they were designed to impact. In this paper we look at several issues that may help explain why there have been such divergent results between on one hand, observational studies and small scale psychosocial experiments and on the other hand, large-scale randomized clinical trials designed to impact health outcomes. We draw largely on the literature which relates social networks and support to cardiovascular and cerebrovascular disease. In order to understand the divergent results, we employ life course models of health and development to focus on the issues of timing and dose of interventions. We will consider the following questions: First, what pattern do social networks follow across the life course? That is, in the absence of organized interventions, how much does network structure or function evolve over the life course: is network structure or function largely immutable after early adulthood or is it dynamic into old age? Are there either socially (e.g., retirement or widowhood) or physiologically (e.g., early childhood or in the aftermath of a major health crisis) defined “elbow” points at which people frequently experience change in the extent or quality of their social ties?