Chronic Disease I

This video provides a simple introduction to the problem of chronic diseases (also known as noncommunicable diseases, or NCDs) using the example of South Asia. Four questions are addressed:

What characterizes chronic diseases? Chronic diseases have common features that relate to health status and health-related treatment: 1. They are not transmitted from person to person (not “contagious” or “infectious”); 2. Different chronic diseases may share related risk factors and may co-exist; that is, a person can have more than one chronic disease at the same time; 3. There can be a long latency between a person’s first exposure to risk(s) and the time when they ultimately develop clear symptoms of the disease; 4. Noncommunicable diseases are chronic, or long-lasting; this means treatment must continue over a long period of time; 5. They have a “cluster effect” on both mortality (premature mortality) and morbidity (impaired quality of life); that is, symptoms and risk factors can co-exist and interact, contributing to worsened symptom severity, illness, and the possibility of premature death. In addition to these five health-related consequences, chronic diseases also have substantial non-health consequences. For instance, they can affect economics (ability to work, other costs) and other social factors related to quality of life.

How many people in the world suffer from chronic diseases? About 65 percent of all deaths in the world each year are due to chronic diseases. Three quarters of these deaths are caused by just four diseases: cardiovascular disease and stroke, chronic lung disease, diabetes, and cancers. To these four, we can add mental health disorders if we measure chronic disease effects not only by causing death but also by how they impair quality of life (for instance through a metric called disability-adjusted life years, or DALYs).

What are the leading risk factors and how do they relate to prevention? Primary risk factors for developing a chronic disease include things like: diet, inactivity, use of tobacco, age, family history, etc. Primary prevention consists of making changes (when possible) early on, before the disease takes hold, actually preventing it from developing. Intermediate risk factors are measures that indicate someone is likely to develop a chronic disease, but the disease may still be preventable if risks are addressed and controlled. These include measures such as high blood pressure, elevated blood glucose, and obesity. Changes to control intermediate risk factors are called secondary prevention. Successful secondary prevention can prevent advanced disease.

Why are both local and global context important? Individuals with chronic diseases can develop risk factors based on social or community and household practices (e.g., poor diet, smoking) that are influenced by both local and global factors. Changing local and global factors can change chronic disease risk, because of the long latency—the years it often takes to develop a serious chronic condition. The global transfer of risk—from rich to poor countries, for example, through advertising and other impacts on health habits and choices—often increases the chronic disease risks for populations in the world’s lower-income countries. Yet because most people develop chronic diseases gradually, there is opportunity for intervention. Lowering risks earlier in life can make a huge impact on the disease burden for any population.