There is a great deal of research on the social determinants of health. Most of it points to three overarching factors:
Income inequality. Once a country has reached the point of development where most deaths come not from infectious diseases (tuberculosis, dysentery, cholera, malaria, flu, pneumonia, etc.), but from chronic diseases (heart disease, diabetes, cancer), the economic and social equality within the society is a greater determinant of death rates and average lifespan than the country’s position with regard to others. The United States, for instance, lags behind Japan, Sweden, Canada, and many other less affluent countries in the life expectancy of its citizens. The difference seems to be the size of the gap between the most and least affluent segments of the society.
Social connectedness. Many studies indicate that “belonging” – whether to a large extended family, a network of friends, a social or volunteer organization, or a faith community – is related to longer life and better health, as well as to community participation.
Sense of personal or collective efficacy. This refers to people’s sense of control over their lives. People with a higher sense or stronger history of efficacy tend to live longer, maintain better health, and participate more vigorously in civic life.