Chronic Obstructive Pulmonary Disease (COPD) - What Causes It?

COPD and its Causes

Chronic Obstructive Pulmonary Disease (COPD) is partially reversible airflow obstruction caused due to inflammation resulting from inhalation of toxins. Smoking is regarded as the most important risk factor in the development of COPD. Research has conclusively shown that long-term smokers of cigarettes are at increased risk of getting COPD. COPD takes years to develop and progress. Long term smokers generally exhibit symptoms of COPD in their forties or fifties if they had been smoking for about 20 years of their life.

COPD comprises of two disease conditions - chronic obstructive bronchitis and emphysema. Many patients have features of both though they may appear together or separately.

It is estimated that nearly 24 million people in the US have airflow limitation, of which nearly 12 million suffer from COPD. COPD is the 4th leading cause of deaths in the US.

COPD and Chronic Bronchitis

COPD could be the resultant progression of acute cough that causes inflammation and swelling of the mucus lining of the airways in the lung called bronchi. This leads to production of excessive mucus that settles in the lungs. This in turn, sets off chronic cough lasting at least 3 months and upto 2 successive years in duration. The presence of excessive mucus and cough result in constriction of airways that causes shortness of breath normally associated with chronic bronchitis.

Nearly all sufferers of chronic bronchitis are known to be smokers or have been smokers in the past. Tobacco smoke from cigarettes causes irritation to the airways.

COPD and Emphysema

Emphysema occurs when tiny air sacs called alveoli get affected by inhaled toxins and do not function normally. These air sacs have stretchy tissue that stretch when air is breathed in and contract when air is let out from the lungs. Within these air sacs, blood gets infused with oxygen in place of carbon dioxide left due to metabolic activity.

Emphysema causes the air sacs to collapse when an individual breathes out, trapping bad air in the lungs. This makes it hard for new air that is rich in oxygen to enter the air sacs. Damaged air sacs provide lungs with inadequate air, making one feel shortness of breath. When the air sacs get enlarged and finally collapse, they do not regenerate or get replaced. This is why damage to lungs is irreversible.

COPD and Genetic Causes

Genetic factors also contribute to COPD though such cases are much rarer in occurrence. A genetic disorder known as alpha-1 antitrypsin deficiency inhibits the production of a protein that is essential to help protect lungs from damage. In smokers, it markedly influences susceptibility to the disease with many people showing symptoms of emphysema as early as in their thirties and forties. In non-smokers, this deficiency is not known to trigger COPD until very advanced age.

Other Causes of COPD

Though of lesser significance when compared to cigarette smoking, low body weight at birth, childhood respiratory diseases, secondhand cigarette smoke exposure, occupational dust like mineral dust, cotton dust and chemical fumes are also known to be contributors to the risk of COPD.