Infectious diseases are causing fewer deaths and illnesses worldwide than two decades ago, with fewer kids dying, but younger and middle-aged adults are bearing more of the overall medical burden

Global study notes progress against infectious diseases

Dec 13, 2012 (CIDRAP News) – Infectious diseases are causing fewer deaths and illnesses worldwide than two decades ago, with fewer kids dying, but younger and middle-aged adults are bearing more of the overall medical burden, according to a massive multipart study published today in The Lancet.

Titled the Global Burden of Disease Study 2010 (GBD 2010), the report represents the biggest systematic effort to portray the world's distribution and causes of a wide range of major diseases, injuries, and health risk factors, and the first since a 1990 GBD study was commissioned by the World Bank, according to a Lancet press release.

The latest effort took 5 years and involved 486 authors in 50 different countries. The Lancet today released an online issue containing the study's seven main articles plus eight related commentaries from experts.

The study was led by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, with main collaborators at the University of Queensland, Harvard School of Public Health, Johns Hopkins Bloomberg School of Public Health, University of Tokyo, Imperial College London, and World Health Organization (WHO).

This is the first time The Lancet has ever dedicated an entire issue to a single study, which journal editors will officially launch tomorrow at The Royal Society in London.

Christopher Murray, MD, DPhil, director of IHME, said in the press release e-mailed to reporters that study findings enable policymakers, health leaders, and informed citizens to see the big picture and weigh different factors such as specific diseases, risk factors, and demographics to understand the most important drivers of health loss.

Unlike the 1990 GBD study, the new study includes data generated from different points in time, allowing researchers to track how health indictors have changed over the last two decades. Another of the study's main findings is that since 1970 men and women across the world have gained slightly more than 10 years of life expectancy, though they spend more years livings with injury and illness.

Despite the global gain in life expectancy, some countries have seen declines, according to the first of the seven study articles. The authors reported that between 1970 and 2010 the AIDS epidemic in southern sub-Saharan Africa dropped the life expectancy for men by 1.3 years for women by 0.9 years.

In the second paper, which addressed the leading causes of death, researchers reported that deaths attributed to communicable, maternal, neonatal, and nutritional causes dropped by around 17% between 1990 and 2010. A substantial part of the decrease was driven by reductions in deaths caused by diarrheal disease, lower respiratory tract infections, neonatal conditions, measles, and tetanus.

However, despite the overall global decrease, communicable, maternal, and neonatal causes still accounted for half of all premature deaths in sub-Saharan Africa in 2010, the group reported. "The burden of HIV and malaria remain high, despite concerted efforts to tackle these communicable diseases in recent years," they wrote.

In articles that addressed healthy life expectancy and living with disability, researchers noted that over the years, Millennium Development Goals have been crafted to reduce the burden of specific diseases such as HIV, tuberculosis, and malaria, with varying results. Overall, however, disability has changed little, they note. They wrote that the findings are a reminder that health is about more than just avoiding death.

In the commentaries, Richard Horton, MD, editor-in-chief of The Lancet, wrote that infectious diseases are being controlled, but big gaps remain in some of the world's regions where, for example, tuberculosis and malaria each were estimated to have killed 1.2 million people in 2010.

He emphasized that the most affected area remains Africa. "Here, maternal, newborn, and child mortality, along with a broad array of vaccine-preventable and other communicable diseases, remain urgent concerns," Horton wrote.

Margaret Chan, MD, director-general of the WHO, wrote in a commentary that the WHO warmly welcomes the study and that accurate assessments of global health trends is essential for setting health policies. She said in many instances the findings are similar to recent WHO estimates, but some differ substantially.

The world needs common standards for sharing and documenting data, she said, adding that as a next step she will convene an expert group in 2013 to review work on global health estimates and discuss ways to improve estimates.

Chan reminded health officials that the real need is to close data gaps, especially in low- and middle-income countries so that global health groups don't need to rely on statistical modeling for gauging disease burden.