In the next 10 to 15 years, the loss of health and life in every region of the world, including Africa, will be greater from noncommunicable or chronic diseases, such as heart disease, cancer, and diabetes, than from infectious and parasitic diseases. This represents a shift in disease epidemiology that has become the focus of increasing attention in light of global aging.
The myth that noncommunicable diseases are diseases of affluence is dispelled by the results of the Global Burden of Disease project, which combines information about mortality and morbidity to assess the total loss of healthy years of life due to disease and injury. In 2002, the project estimates, noncommunicable diseases accounted for 85 percent of the burden of disease in high-income countries and a surprising 44 percent of the burden of disease in low- and middle-income countries. Noncommunicable diseases already account for as much of the burden of disease in low- and middle-income countries as all communicable diseases, maternal and perinatal conditions, and nutritional conditions. By 2030, according to projections, the share of the burden attributed to noncommunicable diseases in low- and middle-income countries will reach 54 percent while the share attributed to communicable diseases will fall to 32 percent (Figure 6). If we restrict attention to older ages, noncommunicable diseases already account for more than 87 percent of the burden for the over-60 population in low-, middle-, and high-income countries. The critical issue for low- and middle-income countries is how to mobilize and allocate resources to address noncommunicable diseases as they continue to struggle with the high prevalence of communicable diseases.
There is extensive debate about the relationship between increased life expectancy and disability status. The central question is: Are we living healthier as well as longer lives, or are our additional years spent in poor health? Some researchers posit a “compression of morbidity”—a decrease in the prevalence of disability as life expectancy increases. Others contend an “expansion of morbidity”—an increase in the prevalence of disability as life expectancy increases. Yet others argue that, as advances in medicine slow the progression from chronic disease to disability, there is a decrease in the prevalence of severe disability but an increase in milder chronic diseases.
A significant reduction in disability has accompanied the increase in longevity in the United States. However, a recent NIA-sponsored analysis across the Organisation for Economic Cooperation and Development (OECD) member countries documents three patterns of disability trends among older people over the past 5 to 10 years:
- A reduction in severe disability rates in Denmark, Finland, Italy, The Netherlands, and the United States;
- Stable rates, even as the population has aged, in Australia, Canada, and France; and
- An increase in severe disability rates in Belgium, Japan, and Sweden.
There is a great need for cross-national efforts to monitor these trends and understand the causes.
|Communicable, maternal, perinatal, and nutritional conditions||44%||32%|
|Communicable, maternal, perinatal, and nutritional conditions||6%||3%|
Source: Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL, eds. Global Burden of Disease and Risk Factors. Washington, DC: The World Bank Group, 2006.