Abstract
Global public databases now contain extensive information about disease, environment, and society, but much of these data have been used only for descriptive summaries rather than for exploring deeper causes of health differences between countries. This commentary discusses how combining data from multiple international sources can reveal new patterns that support fairer and more effective health policies. Using 2 recent examples, we show how this approach can be used to answer important public-health questions, fill gaps in existing databases, and translate scientific evidence into preventive policy. Future ecological studies should continue to connect health data with environmental and social indicators to better understand and reduce global health inequalities.