One possible influence on health indicators has been thought to be income inequality, particularly within the United States, which has among the greatest disparities in income between the highest and lowest income groups. This result of path analysis shows that states with greater income inequality have higher total mortality rates, higher infant mortality rates, higher low birthweight rates, lower life expectancy, as well as fewer primary care physicians per population. This primary care physician to population ratio is related to all of these health indicators, although the relationship with low birthweight does not reach statistical significance.

Source: Shi L, Starfield B, Kennedy BP, Kawachi I. Income inequality, primary care, and health indicators. J Fam Pract 1999; 48(4):275-284.