The Stressed State of America

A growing body of research demonstrating that widening inequality in the U.S. between the rich and the poor is not just an economic phenomenon -- it has dramatic effects on health as well.

The stresses of poverty in the United States have grown so intense that they are harming the health of lower-income Americans - even prematurely leading to their death. The Hamilton Project at the Brookings Institution finds that stress levels have greatly increased for Americans at all income levels since the 1970s, but especially for low-income groups.

The report doesn't measure stress as we typically think about it in daily life. Instead, the researchers track "stress load," an index of certain biological markers like blood pressure, cholesterol level, and kidney and liver function, that they say are "associated with long-term physiological strain." These metrics are strong indicators of a person's health and mortality, according to the report. These metrics have declined for all income groups, but the declines have been smaller for the upper class, which appears to have been insulated by their wealth, the researchers say. In comparison, health metrics for lower- and middle-income people have worsened far more, exacerbating inequality.

The report, which compares surveys carried out by the Centers for Disease Control and Prevention from 1976-1980 with surveys from 2009-2014, pinpoints several measures of health that have declined over the past decades. While there have been remarkable gains in life expectancy over the nearly 40-year period, the number of Americans who say they are in "very good health" or better has fallen, rates of obesity have risen, and what doctors call "stress load" has spiked.

"The poor have seen really striking increases in the stress load index," said Diane Schanzenbach, one of the report's authors and the director of The Hamilton Project. In many cases, health metrics for the middle class went from being in the middle of the spectrum to being more in line with those of the poor,. Schanzenbach says she found the pattern surprising. "One thing this points to is that everybody outside of the top is suffering."

The share of Americans under the age of 50 reporting excellent or very good health has declined sharply since the 1970s. Researchers speculate that factors like job market stress, depression and the quality of health care and diets could be causing the health of lower-income Americans to diverge from their upper-income counterparts. Lower-income Americans who have struggled economically are more likely to experience financial and psychological stress, be exposed to violence and environmental hazards, receive lower quality health care, eat lower quality food and live in substandard housing, researchers say. The Hamilton Project showed that the life expectancy of low-income workers had stagnated or even fallen over the past 30 years.