Measuring global health: motivation and evolution of the Global Burden of Disease Study

Background People everywhere, but particularly those charged with improving the health of populations, want to know whether human beings are living longer and getting healthier. There is an inherent fascination with quantification of levels and patterns of disease, the emergence of new threats to health, and the comparative importance of various risk factors for the health of populations. Before the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) was initiated, no comprehensive assessments of human health were done. The studies that were available examined single causes and tended to err toward overestimation. As a result, the sum of such estimates of lives lost considerably exceeded even the upper limits of the number of deaths worldwide. The World Bank’s World Development Report 1993, which was focused on health in the developing world, required a comparative, comprehensive, and detailed study of health loss worldwide to provide the basis for objective assessments about the probable benefits of applying packages of interventions. The GBD Study was initiated to fill some of these gaps at the time. Work on GBD began in 1991, with the first preliminary results (for base year 1990) published in the World Development Report 1993. The ensuing vigorous scientific and philosophical debate about the construction of disability-adjusted life-years (DALYs), methods, assump tions, and data sources led to the first complete revision of the GBD 1990 study, which was published in a series of four articles in The Lancet in 1997. Further scientific detail was simultaneously or subsequently published in supporting books and articles. Since that first effort, five cycles of GBD estimates have been published in different forms as a series of updates for the years 1999–2004, 2010, 2013, 2015, and 2016. More than 16 000 peer-reviewed publications and reports have been generated from this work, and references to the GBD Study having been cited more than 700 000 times according to Google Scholar. Governments and the development community have used the GBD data in diverse ways. For example, Public Health England explicitly states that their strategy is based on GBD findings, GBD findings have been used at the highest levels of government in China, and GBD data have been used to inform prioritisation of specific policy interventions in Rwanda and Botswana. Based on searches of government documents available online, 156 country governments reference the GBD Study. Local use appears to be steadily growing, with more countries embarking on subnational assessments with each GBD cycle. Subnational assessments in GBD 2015 included the USA, China, UK, Brazil, Mexico, Japan, Kenya, South Africa, and Saudi Arabia, with additional subnational assessments for India and Indonesia added for GBD 2016. Global organisations such as WHO, the World Bank, and the Bill & Melinda Gates Foundation, use GBD results extensively. Over the years, in response to vigorous scientific critique, philosophical debate, and innovation from authors involved in the study, the GBD Study has continued to grow in scope, relevance, participation, and scale, to the point that it is now arguably the de facto source for global health accounting. In this Viewpoint, we trace the evolution of ten key dimensions of the GBD Study, which, in our view as the two founders of the GBD, have had an important role in increasing the utility, relevance, and integration of the GBD findings in national and global health policy debates, and highlight what we see as some of the principal challenges for the future.