The level of inequality currently occurring between American socioeconomic classes has not been seen since before the Great Depression, according to a study recently published in The Lancet. Income inequality in the USA has increased over the past four decades; the share of incomes going to the wealthiest 10 per cent has increased from 33 per cent of total earnings in 1978 to 50 per cent in 2014.
At the same time, incomes for poor and middle-income Americans have barely changed since the 1970s and, adjusted for inflation, have actually declined since 2000. While life expectancy has risen among middle-income and high-income Americans, it has stagnated and even declined in some poorer American groups.
Changes in individual risk factors such as smoking, obesity, and substance abuse are factors but do not fully explain the steeper gradient. Unequal access to technological innovations, increased geographical segregation by income, reduced economic mobility, mass incarceration, and increased exposure to the costs of medical care might be elements operating against the health of low-income Americans. Without interventions to decouple income and health, or to reduce inequalities in income, we might see the emergence of a 21st century health-poverty trap and the further widening and hardening of socioeconomic inequalities in health.