International comparisons of countries’ health and economic outcomes and subsequent rankings is a popular endeavor in public health research. Though many studies that employ multi-national data for comparisons of international health restrict their research only to similarly performing countries, assessing international health sectors in a broader context that compares countries of different economic standings offers valuable teachings. These juxtapositions can help us understand the success and failure of public health policies across diverse regions as well as to inform potential policy interventions worldwide. For a recent article of The Gerontological Society of America, researchers at the Center or Economic and Social Research and in the School of Gerontology at USC collaborated to examine how disability and morbidity differ across countries, focusing on adults between the ages of 55 and 74. In addition, they related individual-level health outcomes to a country’s macro-level characteristics, such as economic development and inequality.
The study, led by Dr. Jinkook Lee, (Director of the CESR Program on Global Aging, Health and Policy at USC), uses data compiled from The Gateway to Global Aging, a data and information portal, which provides access to easy-to-use individual-level longitudinal data from 10 surveys covering over 30 countries. It also provides harmonized data files that can be used for analyses across countries and in different time periods.
The countries in this study range from developing countries to long-developed ones, have a range of GDP per capita from $11,000 (China) to $91,000 (Luxembourg), and have varying degrees of income inequality, life expectancy, and educational level. There are significant cross-country variations in disability and morbidity. For example, the prevalence of disabilities affecting activities of daily living (ADL) among men 55-74 years of age ranges from as little as 3-4 percent in Korea, Japan and Switzerland to 13-14 percent in China, Estonia, and England. For women, the prevalence of ADL disability ranges from 2-4 percent in Korea and Switzerland to over 15 percent in China, Mexico and England. The variations across countries in the study for morbidity is also substantial. The prevalence rate for diabetes varies as much as threefold for men and fivefold for women; for heart disease, it varies fivefold for both men and women; and for stroke, it varies fourfold for men and threefold for women.
The study also found that in general, there is no significant association between national indicators of economic conditions and reported disease prevalence for men. Specifically, there is no association for men between country-specific disease prevalence and the level of GDP or the level of income inequality (based on the Gini coefficient). Additionally, educational attainment and life expectancy is not related to the frequency of heart disease, diabetes, stroke, hypertension or arthritis. However, ADL disability for men is less prevalent in countries with higher life expectancy; whereas for women, ADL disability is more likely in countries with higher income inequality and lower life expectancy. For women, on the other hand, higher GDP countries have a lower prevalence of hypertension, diabetes is less prevalent in countries with more inequality, heart disease is less prevalent in countries with higher life expectancy, and stroke is more prevalent where women have high education.
While this study is observational and descriptive, it adds to the body of knowledge on the variability and substantial heterogeneity in the prevalence of disability and morbidity across countries, and suggests that there is vast room for improving population health. Understanding why some countries do much better than others as far as disability and morbidity prevalence rates are concerned is important in being able to reduce existing gaps and to improve population health world-wide.