The Global Burden of Diseases, Injuries, and Risk Factors (GBD) enterprise is a systematic, scientific effort to quantify the comparative magnitude of health loss due to diseases, injuries, and risk factors by age, sex, and geography for specific points in time. The GBD construct of the burden of disease is health loss, not income or productivity loss. 1 For decision makers, health-sector leaders, researchers, and informed citizens, the GBD approach provides an opportunity to see the big picture, to compare diseases, injuries, and risk factors, and to understand in a given place, time, and age-sex group what are the most important contributors to health loss. The Global Burden of Disease Study 2010 (GBD 2010) builds on the earlier versions for 1990, 1999–2002, and 2004 sponsored by the World Bank and WHO. 2–10 A more thorough description of the context, objectives, key definitions, and metrics used in GBD 2010 is provided in the appendix. Previous GBD studies have led to national burden of disease studies in at least 37 countries and subnational studies in eight countries. GBD 2010 was implemented as a collaboration between seven institutions: the Institute for Health Metrics and Evaluation as the coordinating centre, the University of Queensland School of Popu lation Health, the Harvard School of Public Health, the Johns Hopkins Bloomberg School of Public Health, the University of Tokyo, Imperial College London, and WHO. The study was designed to address key limitations of previous studies, such as the absence of uncertainty intervals, and to solicit the input of many expert advisers across the spectrum of diseases and risk factors. This study represents a great expansion in the scope of work from previous GBD revisions, including a larger disease and injury cause list, more risk factors, many more age groups, and an assessment for three time periods. Furthermore, a completely revised and improved set of estimation methods has been developed; most notably, the prevalence of diseases and their sequelae is estimated using statistical inference on all available data.

A key aspect of the study is the hierarchical cause list for 291 diseases and injuries. This list has four levels of diseases and injuries and a fifth level for sequelae (appendix p 6). The 1160 sequelae are designed to capture the direct consequences of disease or injury that are not otherwise captured elsewhere in the cause list. Across sequelae, there are 220 common sequelae called health states in GBD 2010. For example, anaemia is identified as a sequela of 19 diseases in the cause list. Three health states are associated with anaemia: mild anaemia, moderate anaemia, and severe anaemia. For each of the health states, a lay description was developed for use in the empirical assessment of disability weights. As with diseases, we have developed a hierarchical list of 69 risk factors for which we have developed estimates for 67 (appendix p 6).