What is chronic obstructive pulmonary disease?
Chronic obstructive pulmonary disease or COPD is a disease consisting of three related pulmonary diseases: asthma, bronchitis and emphysema. In each of these diseases, there is an obstruction to the normal air flow through the airways and out of the lungs. The obstruction is usually permanent and tends to become worse over time.
Normally, obstruction to the air flow in asthma patients is reversible. Once the asthma attack passes, the flow out of the lungs goes back to normal. However, if asthma is not treated, it leads to chronic inflammation and development of permanent obstruction. A patient with this form of asthma is considered to have COPD.
Patients with chronic asthma, bronchitis or emphysema are often referred to as chronic asthma, chronic bronchitis or chronic emphysema patients, rather than patients with COPD. However, it is today believed that it is better to categorize them as chronic COPD, because they often present with a variety of lung-related symptoms. This is especially logical because these conditions tend to overlap. For example, a chronic asthma patient may often exhibit symptoms of bronchitis or emphysema, and vice versa.
Causes of chronic obstructive pulmonary disease
There are three main causes of COPD - smoking, including second-hand smoke, air pollution and alpha-1 antitrypsin deficiency.
Smoking is considered to be the number one cause of COPD in the United States, being responsible for as much as 90 percent of all cases of this chronic disease. It is estimated that 15 percent of all cigarette smokers have or will have COPD if they do not stop smoking. Smokers with COPD have higher death rates than non-smokers with the same disease and they are also at higher risk of suffering from respiratory problems, such as cough and shortness of breath, lung infections and decreased lung function.
As for the air pollution, it is not clear how much outside pollution of the air influences the risk of COPD, but it is certain that indoor air pollution, for example from stoves, plays a significant role. Occupational pollutants, affecting people who are exposed to certain chemicals and substances at work, is also a major factor for developing COPD.
Alpha-a antitrypsin (AAT) deficiency is a well-established cause responsible for about one percent of all cases of COPD. This is a fairly rare genetic disorder that affects the way the airways work. AAT is produced in the liver and one of its roles is to block the damage that an enzyme called elastase causes on elastin fibers of the airways and alveolar walls. People born with this deficiency are likely to suffer from emphysema by the time they are 30 or 40 years old.