Background: Social inclusion concerns people's basic needs as well as their ability to participate fully in society. In some ways, it encompasses all of the societal and economic conditions - and inequities - that underlie our health: our neighborhood, income, job, opportunities, support network, and other resources. But it also includes a political dimension because it relates to people's involvement in decision-making processes and their access to power and institutions.

The opposite of social inclusion is social exclusion, which can result from racism, discrimination, stigmatization and hostility as well as structural disparities and neglect. When individuals are made to feel less valued or have no control over their work and living conditions, they not only experience increased stress and anxiety but they feel disempowered, contributing to riskier behaviors and abuse, job and income instability, domestic strife, and isolation. Those consequences can in turn lead to higher social costs in terms of health care, welfare, crime, and lost productivity.

Social exclusion is tied to material conditions as well. When people are denied jobs or home loans; when they don't have access to decent, affordable housing, a good education, or reliable transportation; when their income is insufficient; when they lack opportunities to engage in civic life and can't gain access to other resources vital to their prosperity - all of these increase their likelihood of disease and premature death. For especially vulnerable populations like children, the effects can have a life-long impact even after their conditions improve - what experts like Dr. Jack Shonkoff have termed the "pile up" of risk or disadvantage.

Unlike absolute indicators, social inclusion or exclusion is measured in terms of relative advantage or deprivation within a society. Context matters - after all, the difference between living well or poorly on $1,200 per month depends on the society in which you live. Obviously hunger and homelessness exist even in wealthy nations like the U.S., but relative poverty, for example, gives us a broader picture of basic necessities, including: the ability to fix or replace something that breaks; money for school trips, convenience items and special occasions; good credit; insurance and protections in case of emergency; and collateral for home, car and educational loans.

Relative poverty has a powerful effect on health: People with higher incomes not only live longer, they are healthier. Children in poor families are seven times as likely to be in poor or fair health as children in the highest-income families, and lower-income adults are more likely to smoke, be obese, have diabetes and have heart disease.

Another important component of social inclusion is social support. Today, one in four Americans say they have no one to talk with about important matters - a number that has tripled in the last 20 years. The problem is not individual, it's structural. We work more hours annually than almost every country in the world, even Japan, and we spend on average 50 minutes a day commuting. It's no wonder that many of us are not spending enough time with our families, have cut back on volunteering and outside activities, and feel alone. Isolation is deadly, as researcher Lisa Berkman has shown, increasing the risk of nearly every cause of death.

Strengthening family ties and personal connections is certainly important to improve health. But that's only one piece of the puzzle, because the societal factors that most influence inclusion or exclusion are beyond an individual's control. Investing in our neighborhoods and schools; providing secure jobs with career ladders, good benefits and adequate income; improving work conditions; enforcing civil rights laws; supporting families and children; and above all, creating a society that works for everyone - these are the ingredients for a more inclusive, healthier nation.