National Level Social Determinants of Health and Outcomes: Longitudinal Analysis of 27 Industrialized Countries

To improve health, it is important to understand the social determinants of health (SDH). This study aimed to identify the SDH through national-level indices in industrialized countries. To examine the SDH, we conducted a longitudinal analysis using a panel regression. We sampled from 27 Organisation for Economic Co-operation and Development (OECD) member countries. We chose 19 indices across four categories of health outcomes, which are the socioeconomic environment, the physical environment, health behavior, and health services. Japan ranked in the highest tier for all outcome categories, followed by Iceland, Sweden, and Switzerland. Gross domestic product (GDP, per capita), unemployment, nitrogen oxides (NOX, kilograms per capita), tobacco consumption (SMO, grams per capita [15+]), sugar intake, fat intake, and number of doctors (DOC, per 1,000) had statistically significant effects on life expectancy at birth. GDP, NOX, alcohol consumption, SMO, DOC, total health expenditure (THE, GDP percent), and vaccination coverage for measles (VACCINE, percent) were associated with mortality. In the case of potential years of life lost (PYLL), GDP, NOX, alcohol consumption (ALC, liters per capita [15+]), SMO, DOC, THE, and VACCINE were statistically significant. GDP, school life expectancy, wastewater treatment rate, and VACCINE were associated with the infant mortality rate (IMR). Combining all of the results shows that to improve national-level health outcomes, tobacco and alcohol controls and nutritional policies should be strengthened first, as they will contribute more to mortality and PYLL. Vaccinations will contribute more to IMR and PYLL reductions.