Before the early 1990s, there was no comprehensive and internally consistent source of information on the key challenges to global health. In 1991, with efforts led by Christopher J.L. Murray and Alan Lopez, the World Bank and the World Health Organization launched the Global Burden of Diseases, Injuries, and Risk Factors Study 1990, a comprehensive assessment of the state of the world’s health. The advantage of the Global Burden of Disease (GBD) approach is that consistent methods were applied to critically analyze available information on each condition, make this information comparable and systematic, estimate results from countries with incomplete data, and produce results using standardized metrics.
In 2012, data from GBD 2010 were published, providing results for 1990, 2005, and 2010. Hundreds of collaborators reported summary results for the world and 21 epidemiologic regions, covering 291 diseases and injuries, 1,160 sequelae of these causes, and mortality and burden attributable to 67 risk factors. GBD 2010 addressed a number of major limitations to previous analyses, including strengthening the statistical methods used for estimation and using disability weights derived from surveys of the general population. Metrics produced include leading causes of death, years of life lost, years lived with disability, and disability-adjusted life years (DALYs), which are the years of healthy life lost by a person due to death or disability.
In general, communicable, maternal, neonatal, and nutritional conditions decreased both in absolute terms and relative to noncommunicable diseases between 1990 and 2010, with the exception of malaria and HIV/AIDS. The burden of noncommunicable diseases has been increasing, with the largest increases associated with diabetes. The leading risk factors for disease burden changed substantially between 1990 and 2010. In 1990, the leading risk factor was childhood underweight, but it ranked eighth in 2010. Conversely, increases were seen in DALYs due to obesity, high fasting plasma glucose levels, diets high in sodium, diets low in whole grains, drug use disorders, and lead exposure.
Three broad transitions explain much of the changing pattern in global health over the period studied: demographic changes, changes in causes of death, and changes in causes of disability. Demographic changes (population growth and aging) are the key drivers of increases in the burden of noncommunicable diseases. The second major transition is the change in age- and sex-specific rates of death associated with diseases and injuries, especially the decreases in DALYs due to communicable, maternal, neonatal, and nutritional diseases. Finally, there was a profound shift toward a greater fraction of the burden of disease from disability than from premature death. These transitions, along with local variations in disease burden, have led to important differences among countries.
The results from GBD 2010 will prove useful for benchmarking progress; comparisons over time and across countries can help place local performance in health improvement in context. Quantifying the burden of disease helps identify conditions and risk factors to target and provides important input into health policy discussions.
Estimates of disease burden will improve as further data are collected and methods are refined. GBD study updates will be released annually, and assessments based on the latest available evidence will be made accessible to the general public, health professionals, researchers, and decision-makers. This continuous revision will facilitate incorporation of improvements in estimation. In time, the researchers hope that the GBD approach will be widely used to understand patterns of health within countries due to differences in geographic region, social class, or race or ethnicity.
Murray CJL, Lopez AD. Measuring the Global Burden of Disease. New England Journal of Medicine. 2013; 369:448-457.