The association between wealth and health across the life-cycle: Using age and sex-stratified health outcomes and determinants to identify heterogeneous relationships

Within a global landscape of consistently rising health care costs, understanding the drivers of health becomes increasingly more urgent.  This paper analyzes the relationship between health and wealth across age and time, with a focus on how the association between health and wealth changes throughout the life-cycle. We use measures of mortality and morbidity from the Global Burden of Disease (GBD) 2013 study, disaggregated by age for 188 countries around the world. We estimate the relationship between health outcomes and known determinants such as income, education, socio-political context, and epidemiological and demographic variables. When possible, these variables are stratified by age and sex. Our primary goal is to measure the association between national income and population health for different age and sex-groups, and assess if there are heterogeneous effects. We use simultaneous estimation of a system of equations to efficiently estimate heterogeneous income effects, with each equation measuring the unique effect of health determinants of age and sex specific mortality and morbidity rates. Based upon this research, we describe a generalized model that reflects the evolution of health across the life-cycle throughout the process of economic development around the world, and highlights the underlying patterns across age and sex groups. By highlighting the complex relationship between age-sex specific health outcomes and economic development, and how these relationships change throughout the life cycle, this work provides information about the levers that policy makers, public health practitioners, and development stakeholders can employ to improve population health.