Study Overview
The new Global Burden of Diseases, Injuries, and Risk Factors Study (the GBD 2005 Study), which commenced in the spring of 2007, is the first major effort since the original GBD 1990 Study to carry out a complete systematic assessment of the data on all diseases and injuries, and produce comprehensive and comparable estimates of the burden of diseases, injuries and risk factors for two time periods, 1990 and 2005. By November 2010 the project will produce a final set of estimates.
The GBD 2005 Study brings together a community of experts and leaders in epidemiology and other areas of public health research from around the world to measure current levels and recent trends in all major diseases, injuries, and risk factors, and to produce new and comprehensive sets of estimates and easy-to-use tools for research and teaching. It is led by a consortium including Harvard University, the Institute for Health Metrics and Evaluation at the University of Washington, Johns Hopkins University, the University of Queensland, and the World Health Organization (WHO). This ambitious effort will be conducted systematically and transparently; both its methods and results will be made available to the public.
Background
The original Global Burden of Disease Study (GBD 1990 Study) was commissioned by the World Bank in 1991 to provide a comprehensive assessment of the burden of 107 diseases and injuries and ten selected risk factors for the world and eight major regions in 1990. The methods of the GBD 1990 Study created a common metric to estimate the health loss associated with morbidity and mortality. It generated widely published findings and comparable information on disease and injury incidence and prevalence for all world regions. It also stimulated numerous national studies of burden of disease. These results have been used by governments and non-governmental agencies to inform priorities for research, development, policies and funding.
The principle guiding the burden of disease approach is that the best estimates of incidence, prevalence, and mortality can be generated by carefully analyzing all available sources of information in a country or region, and correcting for bias. The disability-adjusted life year (DALY) , a time-based measure that combined years of life lost due to premature mortality and years of life lost due to time lived in health states less than ideal health, was developed to assess the burden of disease. The GBD 1990 Study represented a major step in quantifying global and regional effects of diseases, injuries, and risk factors on population health.
In 2000, the World Health Organization began publishing regular GBD updates for the world and 14 regions. These revisions were aided by methodological improvements and more extensive data collection that covered key aspects of the GBD, including mortality estimation, cause of death analysis, and measurement and valuation of functional health status. Standardized concepts and approaches to comparative risk assessment were applied to over 25 risk factors. New estimates for 2001 were published as part of the second revision of the Disease Control Priorities Project. In addition to these continuing efforts for better epidemiological quantification, the philosophical underpinnings for quantifying population health have been extensively explored as part of the overall effort to foster summary measures of population health.
Why update the GBD estimates?
The Global Burden of Diseases, Injuries and Risk Factors Study is an evidence-based and scientific pursuit. While various groups have published partial updates of GBD rankings, there has not yet been a comprehensive and systematic revision. As a result, burden estimates today contain some outdated, and often, inconsistent information. Furthermore, patterns of disease and disability and their risk factors have altered dramatically and need to be reassessed in a newly comprehensive study.
Today, there is great demand for global burden estimates. Research and advocacy groups have brought new conditions to the awareness of the public health community. The GBD 2005 Study will review the magnitude of these conditions compared to other causes of health burden. Also, researchers have significantly improved methods for burden assessment since the original GBD 1990 Study. These new tools can markedly enhance the validity of estimations, particularly for ranking risk factors and disabilities. More and more researchers, especially in the developing world, are engaged in burden work than ever before. A new structured study will take advantage of the opportunity to bring these global researchers together to communicate and work collaboratively in an environment that is strongly seeking new burden statistics. Moreover, the unprecedented money and attention now pouring into international health has made the need for an accurate assessment of global health patterns a matter of utmost urgency. A thorough GBD reassessment will ensure that the global health community bases its research and policies on complete, valid, and reliable information.