Infant mortality, per capita income, and adult illiteracy: an ecological approach.

The ecological association of infant mortality rate (IM) with per capita income (PI) and prevalence of adult illiteracy (AI) has been studied using countries as the unit of analysis. A negative association between IM and PI in 1960 and 1982 has been observed (sample correlation coefficient [r] = -.625 and r = -.729, respectively; P less than .05). A correlation between IM and AI has been found for both men and women (r = .827 and r = .855, respectively; P less than .05). The ecological relative risks were 7.43 for men and 5.82 for women (95% confidence intervals: 5.16-10.71 and 4.36-7.75, respectively). The association of IM and PI shows a slight but not significant improvement between 1960 and 1982. AI can be considered a good predictor of IM in countries.