Development of a global integrated environmental quality index for population health research

Population health is influenced by a complex mixture of environmental stressors, yet their integrated effects remain understudied. A globally comparable environmental quality index is warranted to capture the combined environmental risk and its public health implications, enabling cross-country comparisons and guiding intervention priorities.

Five environmental domains (air pollution, vegetation and water cover, light pollution, extreme climate events and meteorology) comprising thirteen environmental features were selected. The D-CRITIC method was adopted to assign objective weights to each feature, and a composite Global Environmental Quality Index (G-EQI) was constructed to quantify the environmental quality across 96 countries, where higher G-EQI values indicate less favorable environmental conditions. Temporal patterns between G-EQI and non-communicable diseases (NCDs) mortality rates were examined. Sensitivity analyses were conducted to evaluate robustness.

Vegetation-related features carried relatively high weights in the G-EQI framework, with NDVI having the highest weight. Kuwait and Canada recorded the highest G-EQI scores among developing and developed countries, respectively, indicating least favorable environmental conditions. Several countries exhibited strong directional agreement between changes in G-EQI scores and NCD mortality rates. Lagged associations were observed in 18 countries, suggesting potential delayed responses of NCD outcomes to environmental conditions.

This study presents a globally comparable, multi-domain G-EQI that captures cross-country disparities in environmental risk burden. The findings provide insights into temporal patterns between environmental quality and NCD mortality. The G-EQI may serve as a tool for international environmental monitoring and benchmarking, supporting environmental and public health interventions.