How do inequality and health relate? Increasing evidence from scientists the world over indicates that many health outcomes — everything from life expectancy to infant mortality and obesity — can be linked to the level of economic inequality within a given population. Greater economic inequality appears to lead to worse health outcomes.
By greater inequality, epidemiologists — the scientists who study the health of populations — don’t just mean poverty. Poor health and poverty do go hand-in-hand. But high levels of inequality, the epidemiological research shows, negatively affect the health of even the affluent, mainly because, researchers contend, inequality reduces social cohesion, which leads to more stress, fear, and insecurity for everyone.
Economists and health experts have known for years that people who live in poorer societies live shorter lives. But research also points to an additional factor in explaining life expectancy: a society’s level of inequality. People live longer in nations with lower levels of inequality, as measured here by the Gini coefficient, a standard global benchmark.
In 2012, nations with the smallest income gaps between households at the 90th and 10th percentiles had significantly fewer infant deaths than other nations. A household at the 90th percentile has more income than 90 percent of households.
Researchers are also finding links between inequality and mental health. Countries with larger rich-poor gaps have a higher risk of schizophrenia incidences. In general, a 0.2 point increase in a country’s Gini coefficient results in eight additional incidences of schizophrenia per 100,000 people. Researchers believe that higher inequality undercuts social cohesion and capital and increases chronic stress.
Extreme inequality appears to affect how people perceive their well-being. In nations where the top 1 percent hold a greater share of national income, people tend to have a lower sense of personal well-being.
Inequality and Health in the United States
The same association between high economic inequality and poor health can be observed within the United States.
What’s true on the international level also holds true within the United States: People live longer in the nation’s more equal states.
U.S. households with annual incomes below $50,000 report higher levels of stress than other families. Average stress levels have been falling since the 2007-2008 financial crisis, but the stress-gap between rich and poor households has been increasing.
The lower American workers rank on the national economic ladder, the more likely their jobs will be physically demanding. Such jobs can lead to more stress, both physical and mental — and higher medical bills. Workers in physically demanding jobs also typically retire earlier, before they can claim full Social Security benefits.
The bottom third of U.S. earners tend to retire earlier than other Americans, in part because their jobs are often more physically demanding. Because American workers cannot claim full retirement benefits before age 66, this trend exacerbates economic inequality among seniors.
Millions of American families are currently facing economic hardship in their retirement years. The chief executives of large U.S. corporations, meanwhile, are sitting on massive retirement nest eggs. In 2015 the retirement savings of just 100 top CEOs totaled $4.9 billion, a sum equivalent to the entire retirement savings of 41 percent of American families, 50 million Americans in all.