Global Burden of Disease 2010 Study published

Executive summary - The Lancet

13 DECEMBER 2012 - LONDON - The Global Burden of Disease Study 2010 (GBD 2010) is the largest ever systematic effort to describe the global distribution and causes of a wide array of major diseases, injuries, and health risk factors. The results show that infectious diseases, maternal and child illness, and malnutrition now cause fewer deaths and less illness than they did twenty years ago. As a result, fewer children are dying every year, but more young and middle-aged adults are dying and suffering from disease and injury, as non-communicable diseases, such as cancer and heart disease, become the dominant causes of death and disability worldwide. Since 1970, men and women worldwide have gained slightly more than ten years of life expectancy overall, but they spend more years living with injury and illness.

GBD 2010 consists of seven Articles, each containing a wealth of data on different aspects of the study (including data for different countries and world regions, men and women, and different age groups), while accompanying Comments include reactions to the study's publication from WHO Director-General Margaret Chan and World Bank President Jim Yong Kim. The study is described by Lancet Editor-in-Chief Dr Richard Horton as "a critical contribution to our understanding of present and future health priorities for countries and the global community."

IHME press release

13 DECEMBER 2012 - The Global Burden of Disease Study 2010 (GBD 2010) was a collaborative project led by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington. The findings were announced at the Royal Society in London and published in The Lancet, the first time the journal has dedicated an entire triple issue to one study. The seven scientific papers and accompanying commentaries provide a new platform for assessing the world’s biggest health challenges, and then finding the best ways to address them.

The study reveals massive shifts in health trends around the world since 1990, the starting point of the first Global Burden of Disease study. Since that time, the world has grown considerably older. Where infectious disease and childhood illnesses related to malnutrition were once the primary causes of death, now children in many parts of the world – outside of sub-Saharan Africa – are more likely to live into an unhealthy adulthood and suffer from eating too much food rather than too little. Lastly, health burden is increasingly defined by what’s making us sick rather than what’s killing us. The biggest contributor to the world’s health burden used to be premature mortality – driven by more than 10 million deaths in children under the age of 5 – but now the disease burden is caused mostly by chronic diseases and injuries such as musculoskeletal disorders, mental health conditions, and injuries. This burden intensifies as people live longer...

Hundreds of researchers worldwide pioneered new ways of analyzing disease

GBD 2010 started in 2007. IHME served as the coordinating center working with six other core collaborators: the University of Queensland, Harvard School of Public Health, the Johns Hopkins Bloomberg School of Public Health, the University of Tokyo, Imperial College London, and the World Health Organization. The researchers set out to completely overhaul the Global Burden of Disease process first created in the early 1990s by Dr. Murray and Dr. Alan Lopez, one of the founders of the Global Burden of Disease and Head of the School of Population Health at the University of Queensland. The project was initially funded by the World Bank. GBD 2010 grew to become a truly global effort. From 302 institutions and 50 countries, including 26 low- and middle-income countries, 486 authors have conducted the largest systematic scientific effort in history to quantify levels and trends in the world’s health problems. The work was funded by the Bill & Melinda Gates Foundation.

First, researchers gathered more data than had ever been amassed for a health study. Using vital registration systems, surveys, censuses, and a meta-analysis of all available randomized controlled trials, they created a database covering everything from AIDS to zinc deficiency. They hammered out a set of criteria to determine which data should be included in the final analysis and which should not. If a study was not rigorous or was too specific to one place and one time to be broadly applicable, it was excluded. New analytical tools were developed to fill gaps in the data for countries where information is sparse. They tested those methods by using them to make estimates in areas where health data are more readily available, such as the United States or Japan.

Findings show rapid changes in health outcomes

The study underscores significant achievements, such as the dramatic drop in child mortality, which has fallen so quickly that it has beaten every published prediction. But more work remains. Diseases such as diarrhea due to rotavirus and measles continue to kill more than 1 million children under the age of 5 every year, despite effective vaccines against those diseases.While child mortality has decreased, GBD 2010 found a startling 44% increase in the number of deaths among adults aged 15 to 49 between 1970 and 2010. This is in part because of increases in violence and the ongoing challenge of HIV/AIDS, which kills 1.5 million people annually.

Another mixed success is that while the burden of malnutrition has successfully been cut by two-thirds, poor diets and physical inactivity are contributing to rising rates of obesity and other lifestyle-related risk factors, including high blood pressure, tobacco smoking, and harmful alcohol use. Dietary risk factors and physical inactivity collectively caused 10% of the disease burden, and the burden due to excess weight and high blood sugar are rising substantially. These findings are consistent with one of GBD 2010’s repeated themes: Disability is causing a greater and greater fraction of the burden of disease as demographics and epidemiology evolve. Much of this burden is caused by a relatively small group of ailments. Researchers examined more than 300 diseases, injuries, and risk factors and found that just 50 distinct causes account for 78% of the global burden. Just 18 of those account for more than half the burden.

When looking at disease burden more broadly, taking into account both years of life lost due to premature death and years lived with disability, the changes have also been dramatic. Neonatal encephalopathy, an often fatal brain condition in newborns, fell out of the 10 leading causes between 1990 and 2010, as did protein-energy malnutrition, the leading cause of starvation. They were replaced by lower back pain and road injuries.

Gap between sub-Saharan Africa and the rest of the world widens

The trends identified in GBD 2010 occur across regions with one notable exception: sub-Saharan Africa, where infectious diseases, childhood illnesses, and maternal causes of death account for as much as 70% of the burden of disease. By comparison, these conditions account for only one-third of the burden in south Asia and Oceania, and less than 20% in all other regions. Additionally, while the average age of death throughout Latin America, Asia, and north Africa increased by more than 25 years between 1970 and 2010, it rose by less than 10 years in most of sub-Saharan Africa. “Sub-Saharan Africa continues to present a special challenge for a variety of methodological, geographic, and economic reasons,” said Dr. George Mensah, Visiting Full Professor at the University of Cape Town and one of the GBD 2010 co-authors. “The evidence base for estimating causes of death in Africa remains limited. The data do show modest progress in lowering child mortality, but communicable and nutritional causes still account for half of premature deaths in Africa. Nearly as troubling is the rising burden of chronic illness, such as stroke and heart disease.” What have been historically considered “Western ailments” also menace millions in Africa, including the very young. Pain, anxiety, and depression – which erode quality of life and productivity – are ranked among the highest causes of years lived with disability throughout sub-Saharan Africa.

“African nations have not even begun to confront the consequences of exploding cases of mental illness, depression, pain, and the enormous burden of substance abuse that stem from those conditions,” said Dr. Felix Masiye, who heads the Department of Economics at the University of Zambia and is working with IHME in Zambia to study health interventions. “The direct link between mental illness and physical well-being is at the core of this unexplored terrain, and can only grow as the years go by.”

GBD 2010 provides the evidence for a range of new research projects and targeted policymaking. It also opens the opportunity for countries to conduct detailed burden studies of their own populations.