Throughout the world, wealth and income are
becoming more concentrated. Growing evidence
suggests that the distribution of income—in addition
to the absolute standard of living enjoyed by the
poor—is a key determinant of population health. A
large gap between rich people and poor people leads
to higher mortality through the breakdown of social
cohesion. The recent surge in income inequality in
many countries has been accompanied by a marked
increase in the residential concentration of poverty
and affluence. Residential segregation diminishes the
opportunities for social cohesion. Income inequality
has spillover effects on society at large, including
increased rates of crime and violence, impeded
productivity and economic growth, and the impaired
functioning of representative democracy. The extent
of inequality in society is often a consequence of explicit policies and public choice. Reducing income
inequality offers the prospect of greater social
cohesiveness and better population health.