Table 3

Estimated percentage difference in IMR associated with city-level predictors stratified by country GDP per capita

Countries below median GDP‡‡
n=168 cities
Countries above median GDP§§
n=118 cities
Test for interaction¶¶
% Difference95% CI% Difference95% CIP value
Population size*0.4−0.2 to 0.91.2−0.5 to 3.00.0017
Population growth rate†−6.5−9.8 to −3.1−5.9−9.8 to −1.90.3833
Living conditions score‡−18.0−26.7 to −8.2−16.3−19.0 to −13.50.0469
Services provision score§−11.7−14.4 to −8.82.7−0.7 to 6.3<0.0001
Population educational attainment score¶0.1−2.0 to 2.14.9−6.3 to 17.40.0067
Availability of mass transit*−6.6−9.9 to −3.2−7.5−18.1 to 4.50.1784
MMR1 coverage††−0.2−0.2 to −0.10.01−0.4 to 0.50.2766
  • *Population size is defined as 1SD higher the population in 2010.

  • †Population growth rate is defined as 1SD higher annual difference in population size from 2010 to 2015.

  • ‡Living conditions score includes per cent of households with piped water in the dwelling, per cent of households with overcrowding (3+ per room) in the house and per cent of population aged 15–17 years attending school.

  • §Services provision score includes per cent of households with water connected to municipal network and per cent of households with sewage system connected to municipal network.

  • ¶Population-level educational attainment score of 3 includes per cent of population aged 25 years or above with complete high school level or above and per cent of population aged 25 years or above with complete university level or above.

  • **Mass transit availability refers to the presence of either subway or bus rapid transit networks;

  • ††MMR1 coverage represents the percentage of 1-year-old children who received the first dose of measles-mumps-rubella vaccine among overall population of 1-year-olds.

  • ‡‡Countries with GDP/capita below the median (US$15 530): Brazil, Colombia, Costa Rica and Peru.

  • §§Countries with GDP/capita above the median (US$15 530): Argentina, Chile, Mexico and Panama.

  • ¶¶Each interaction was tested separately along with the full model. GDP was coded as GDP=0 for countries with GDP/capita below the median, and GDP=1 for countries above the median.

  • Estimates correspond to per cent differences in IMR for 1SD higher SE scores, population size and growth, 1% higher MMR1 coverage and the availability of mass transit.

  • GDP, gross domestic product; IMR, infant mortality rate; MMR1, measles–mumps–rubella vaccine; SE, socioeconomic; 1SD, one SD.