Studies have shown a relationship between income and health—the richer you are, the healthier you are. However, recent research has shown that this is not always the case. In fact, when average income increases above some threshold, that relationship seems to disappear and a new one become apparent. As a nation becomes richer, and more unequal in income distribution, a new positive relationship between income and mortality rates can be seen.

Researchers at Harvard have joined a group who argue that the best way to improve length of life is to create a more equitable sharing of national income. By comparing mortality rates with levels of inequality across states, and controlling for other factors, the more unequal a state's income distribution is, the more likely its citizens were to die. Not only does unequal income affect social services, such as education and public health, but researchers argue that inequality affects individuals' psyches as well. "Wide income distributions create social prejudices and ideas of superiority and inferiority, [and] dominance and subordination," according to one of the researchers.

However, another group of researchers argues that what these people have found is more of a correlation than a causal relationship. In other words, some believe that there is a missing link in this relationship: Income inequality will directly impact this missing link (such as individual characteristics), which will then impact the mortality rate.

Regardless of the outcome, these individuals have given policy makers much to think about, as the issues of income inequality have become more and more apparent. Since 1970, the richest 5% in America saw their average incomes rise from $33,600 to $260,500 per yea; at the same time the average income of the poorest 20% increased from $2,000 to $10,100.

(Updated January, 2004)