NCPA - National Center for Policy Analysis

Researchers Find No Link Between Income Inequality and Health and Mortality

January 4, 2002

New research refutes claims that overall health in a society is negatively affected by inequality of incomes, according to the British Medical Journal. Not to be confused with the well-established findings that higher income is associated with relatively better health and greater longevity, inequality refers to the share of the income pie gotten by lower and higher income groups.

  • A 1992 paper found a strong negative correlation between income inequality and life expectancy among nine Western industrialized countries.
  • Those countries with less income seemed to have higher life expectancy -- a finding replicated in analyses looking at income inequality and mortality in states within the United States.
  • The policy implications were that government should attempt to redistribute income and/or health resources to even up outcomes.

But researchers suggest the previous findings were due to a lack of adjustment for other factors that influence health and mortality, and bias in the selection of countries. Based on better data for 16 western industrialized countries, the association between income inequality and life expectancy has disappeared.

  • An analysis of mortality in a small area in Copenhagen, Denmark found no association between income inequality and mortality after adjustment for individual income.
  • Another finds that most of the correlation between income inequality and mortality in the United States can be explained by differences in average levels of formal education.
  • A study from Japan shows that although income inequality at the district level is weakly associated with poor or fair self-rated health, the association disappears when individual income is controlled for.
  • And a study on the effects of U.S. income inequality on self-reported chronic conditions and depressive and anxiety disorder found strong associations with individual income, but no effect of income inequality as such.

Source: Johan P Mackenbach (Erasmus University), "Income inequality and population health," Editorial, British Medical Journal, January 5, 2002.

For BMJ text

http://bmj.com/cgi/content/full/324/7328/1

 

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