BOSTON – Unhealthy lifestyle habits are largely responsible for heart disease, diabetes, cancer, and lung disease in much of the world, but among the poorest people, much of the noncommunicable disease burden stems from infections and other endemic environmental factors.
Photo credit: Ilvy Njiokiktjien
Cold winters in Malealea, Lesotho force people to cook indoors with poor ventilation. Experts say that chronic respiratory disease is a major problem among the world's poorest people due to exposure to solid biomass fuels such as wood, dung, and charcoal.
Recognition of such fundamental differences in the etiology of noncommunicable diseases (NCDs) – and the endemic causes of those diseases among the world’s poorest billion people – is needed as the United Nations forges ahead with plans to address NCDs on a global scale. That was the conclusion drawn by stakeholders at a meeting aimed at decreasing the burden of noncommunicable diseases in the so-called "bottom billion" – the world’s population living on less than one dollar a day.
"The term ‘endemic’ is significant because it places the emphasis on the diseases that are already there in these populations, in addition to the epidemics of emerging NCDs. We’re expanding the notion of what ‘noncommunicable disease’ is," Dr. Gene Bukhman said at the meeting, which was sponsored by Partners In Health, an international nonprofit organization that provides direct health care services to people living in poverty around the world.
Dr. Gene Bukhman
Over the last two decades, people and organizations have been clamoring for the inclusion of NCDs on the global health agenda. That movement has been newly energized by the United Nation’s announcement last May that it will hold a General Assembly High-level Meeting on NCDs in September. It will be only the second such disease-related meeting that the UN has ever held. The first such meeting in 2001 focused on HIV/AIDS, and is credited with galvanizing global attention and fund-raising efforts for that cause.
Participants at the Partners In Health meeting are working to ensure that the upcoming UN meeting doesn’t overlook the needs of the poorest people in the world.
The primary focus of the upcoming UN meeting will be on "noncommunicable disease" as defined by the World Health Organization in its 2008-2013 NCD action plan: cardiovascular diseases, diabetes, cancers, and chronic respiratory diseases related to the four shared risk factors – tobacco use, physical inactivity, unhealthy diets, and the harmful use of alcohol. Together, these conditions account for approximately 60% of all global deaths, of which 80% occur in low- and middle-income countries, according to WHO.
That "four-by-four" model, however, doesn’t encompass the breadth of chronic conditions seen in the poorest countries, where infection, malnutrition, environmental toxins, and lack of access to care contribute much more to the NCD burden than do lifestyle factors. Taken together, "endemic NCDs" account for nearly 25% of disease among the world’s poorest billion, said Dr. Bukhman, a cardiologist who serves as director of the Harvard Medical School Program in Non-Communicable Disease and Social Change, Boston, and also as the cardiology director for Partners In Health, working in Rwanda.
Infectious origins of many NCDs in poor countries highlight the "false dichotomy" view of NCDs as separate from infectious disease and that scarce resources need be divided between the two camps. "If we pit one set of interventions against another, we’re not going to get very far," said Dr. Paul Farmer, director of Partners In Health.
Neglected Tropical Diseases. Neglected tropical diseases (NTDs) are a prime example of the blurred line between NCDs and infectious disease. The NTDs are not communicable from person to person, and they cause chronic illness that is not typically fatal in the short term but which can severely debilitate and reduce productive capacity, according to Dr. Peter Hotez, Distinguished Research Professor and Walter G. Ross Professor and Chair of the Department of Microbiology, Immunology, and Tropical Medicine at George Washington University, Washington.
Affecting approximately 1.4 billion people worldwide, the NTDs include chronic parasitic infections such as ascariasis, trichuriasis, hookworm, and schistosomiasis. Some of the NTDs cause NCDs, including cardiomyopathy due to Chagas disease, cor pulmonale from schistosomiasis, asthma due to toxocariasis, and inflammatory bowel disease from trichuriasis, said Dr. Hotez, who also serves as president of the Sabin Vaccine Institute, a nonprofit research and advocacy organization that is currently conducting trials on vaccines against hookworm, schistosomiasis, Chagas disease, and malaria.
Together, the NTD global burden in terms of disability-associated life-years is 56.6 million, greater than that of malaria (46.5 million) or tuberculosis (34.7 million), and two-thirds that of HIV/AIDS (84.5 million), Dr. Hotez and his associated reported (N. Engl. J. Med. 2007;357:1018-27).