What is the GBD Study?

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Background

The original Global Burden of Disease (GBD) Study was commissioned by the World Bank in 1991 and provided burden of disease estimates for 1990. New estimates for 2001 were published as part of the second revision of the Disease Control Priorities Project.

The principle guiding the burden of disease approach is that best estimates of incidence, prevalence, and mortality can be generated through the careful analysis of all available sources of information in a country or region, and correction for bias. The disability-adjusted life year, or DALY, was developed to assess burden of disease, 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.

The current study will involve 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. Improved techniques and new data will be used.

Objectives

The current study has two major objectives:

1. To produce estimates of the burden of diseases, injuries and risk factors for 1990 and 2005, organised in 21 regions covering the globe.
2. To develop a series of tools for use by specific audiences, to standardise and broaden burden of disease research and analysis, and to produce publications tailored to policymakers and non-research audience.

Approach

The GBD Study will take 3 years to complete for more than 175 diseases and injuries and more than 45 risk factors, for 21 regions of the world. The GBD Study will not only serve to systematically incorporate the evidence on each major disease and risk factor into a coherent set of epidemiological estimates, but will also provide an opportunity for concerted work on new age-specific and sex-specific mortality estimates, disability weight measurement, estimates of probabilities of disabling sequelae, and standardization of tools and methods for resolving inconsistencies, dealing with missing data and quantifying uncertainty.

The study will conduct epidemiological reviews of all diseases, injuries, and risk factors; estimate mortality and cause of death for all countries in the world; derive new disability weights for an updated list of disabling sequelae, all leading to final, consistent and comprehensive estimates of the burden of diseases, injuries and risk factors for 1990 and 2005.

Benefits

The study will provide four key benefits as a source of accurate knowledge and a vital tool for informed decision-making.

1. Systematic and objective analysis is ensured by separating epidemiological assessment from advocacy, creating evidence-based pictures of health patterns that can subsequently motivate responsible policy formulation and research.
2. Balanced assessment of health problems, which combines information on disease and risk factor causes of premature mortality, morbidity, and disability
3. Assessment of the magnitude of health problems using standard units of measurement, such as disability-adjusted life years (DALYs).
4. Focus on education, training and transparency

Major Activities

The GBD Study is divided into seven major activities with milestones that span the length of the project. Each major activity has been carefully planned to correspond to the work in other activities so that each area progresses at a similar pace. The activities are:

1. Disease, injury and risk factor epidemiological review
2. Mortality estimation
3. Cause of death estimation using population data sources
4. Disability weight measurement and comorbidity corrections
5. Comparative risk assessment
6. Harmonize GBD estimates
7. Creation of curricula and tools and dissemination of results and products