ent fraction of the population needs to be exposed to risk factors across countries. Second, the health risk—“toxicity”—associated with risk factors might differ between countries. For common risk factors, even small differences in toxicity may have large population health effects. Differences in toxicity could occur if population differences in exacerbating or compensatory factors influence the risk of disease. For example, if countries had public policies protecting citizens against deleterious health effects of extreme poverty, we might not see health effects manifest themselves there, even though poverty was present. Third, we would hope to assess in a single model whether social integration and support can account for cross-country differences in life expectancy. In this chapter we examine the first two but do not have adequate data to test the third in a compelling way, except for a comparison of England and the United States.

The lack of truly harmonized individual-level data across countries on relevant exposures and health outcomes over time limits our ability to examine this question. To overcome this limitation, we start by comparing associations between social integration and social support in the United States and England, using data from the Health and Retirement Survey (HRS) and the English Longitudinal Study of Ageing (ELSA). Although not identical, these surveys have very comparable measurements of social networks and social support, as well as comparable data on health conditions and associated risks. We then consider ways in which related psychosocial conditions tapping dimensions of stress may explain observed health variations between the United States and England. We examine these questions for a variety of self-reported outcomes and measured biomarkers of disease. In addition, we use the mortality follow-up in HRS and ELSA to examine impacts of social networks and interactions on all-cause mortality.

Since differences in life expectancy between the United States and England are relatively small, we then examine how 28 industrialized countries vary on several dimensions of social networks and support. In these analyses, we draw on recent data from the Gallup World Poll for Japan and a number of European and North American countries. We present data on the distribution of dimensions of social integration explored in our HRS/ELSA comparisons. Although the items are not fully identical, they provide us with a general overview of variations in these dimensions in a wider set of countries. We conclude with suggestions for carrying this work forward by exploring whether variability in social networks is related to a country’s level of health and well-being.

The chapter is divided into four sections. First, we compare morbidity and health risks in England and the United States by social networks and support, using cross-sectional data from HRS and ELSA. Second, we briefly report on whether other psychosocial stressors often related to social networks may help explain cross-country differences. Third, we examine