Chronic Obstructive Pulmonary Disease (COPD)
Chronic obstructive pulmonary disease, or COPD, is a long-lasting obstruction of the airways that occurs with chronic bronchitis, emphysema, and/or asthma. This obstruction of airflow may be progressive, worsening over time. The diseases that occur with COPD as described below.
Chronic bronchitis is defined as a chronic (ongoing, long-term) cough not caused by another condition that produces sputum (mucus) for 3 or more months during each of the two consecutive years. This definition is mainly used for research purposes in helping to select similar patients for study of their underlying lung disease and possible treatment options.
In chronic bronchitis, the mucous glands in the lungs become larger and more numerous. Irritation of the lining cells of the airways increases the number of gland forming cells. This inflammation thickens the walls of the airway tubes thus narrowing the lumen.
Emphysema is an abnormal, permanent enlargement of the air spaces (alveoli) located at the end of the breathing passages of the lungs (terminal bronchioles). Emphysema also destroys the walls of these air spaces and the attachments to airways. This allows for more deformation of the airways by increasing their ability to collapse. This collapse contributes to the inability of the lungs to empty air, hence resulting in air trapping.
There are three types of emphysema:
- centriacinar emphysema,
- panacinar emphysema, and
- distal acinar emphysema or paraseptal emphysema.
Asthma is a chronic lung disorder that has recurring problems of partial airway obstruction that is usually triggered by stimuli such as allergens or rapid changes in air temperature; patients may wheeze, have labored breathing, cough and feel as though their chest is constriction. When asthmatics are not having an attack their lung function is normal. When airway obstruction becomes fixed, asthma is then considered a form of COPD.
In the United States, approximately 14.2 million people have been diagnosed with COPD, 12.5 million people have chronic bronchitis, and 1.7 million people have emphysema. It is estimated that there may be an additional equal number of US citizens that have COPD, but who have not been diagnosed with the disorder. The number of people with COPD has increased by 41.5% since 1982.
- An estimated 8% to 17% American men and 10% to 19% American women suffer from chronic airway obstruction. This obstruction decreases the rate of airflow through the lungs when a person exhales (breathes out). During the last decade, COPD has increased in women by 30%.
- According to a 1985 study, death rates from COPD for patients aged 55 to 84 years were 200 per 100,000 men and 80 per 100,000 women in the United States. Although men had a higher death rate than women, the mortality rate due to COPD in women is expected to increase.
Worldwide data are sparse. However, because more than 1.2 billion people are exposed to smoking, the number of persons with COPD is probably quite high.
- In 1990, the worldwide prevalence of COPD was estimated to be 9.4 per 1,000 in men and 7.3 per 1,000 in women.
- One study in Spain determined that 9.1% of individuals aged 40 to 69 years had COPD. Of those individuals, 78% were men.
- Overall death rates from COPD vary worldwide. For example, more than 400 deaths per 100,000 men aged 65 to 74 years occurred in Romania, whereas fewer than 100 deaths per 100,000 people in Japan occurred.
- COPD is projected to rank fifth in the world in regard to burden of disease, which includes the costs, mortality, and morbidity.
Medically Reviewed by a Doctor on 1/22/2015
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