Aetiology

Smoking

Smoking is the main risk factor for developing COPD as it causes around 90% of cases (although it can occur in people who have never smoked). Total cigarette consumption in pack years is used to predict the risk of COPD (see Smoking Cessation page). Smoking can also increase the effects of other risk factors such as occupational (see below).

Occupational disease

Along with cigarette smoke other airborne toxins can cause COPD, meaning that a person’s occupation can put them at risk.

Coal dust: Coal miners are at risk of developing COPD due to breathing in dust while working. Although previously coal dust has been shown to cause pneumoconiosis (a scarring disease of lung tissue), research has since shown that it can also lead to the development of COPD.

Asbestos: Exposure to asbestos can cause COPD especially if the person smokes. Asbestos is found in a number of places such as car garages, textile factories, steel factories, and power plants. If someone with COPD comes into contact with asbestos they are more susceptible to further damage. Some people will develop asbestosis first (a form of pneumoconiosis) before developing COPD as a complication.

Genetics

A rare genetic link has been found with people with an alpha-1-antitrypsin deficiency (AATD) more likely to develop COPD under 35 years old. AATD is a lack of the protein alpha-1-antitrypsin (AAT). ATT is produced by the liver to protect the lungs from inhaled irritants such a dust, smoke and bacteria. AATD occurs due to a defect on chromosome 14 which either causes no production of AAT or AAT is produced with structural errors so that it is unable to leave the liver.

AATD will usually present between 20-50 years old with shortness of breath following mild activity, reduced exercise ability and wheezing. Some will show signs of liver damage from birth. Most people with AATD will only be identified after developing lung disease.

Epidemiology

Bibliography:

Aetiology

Chronic Obstructive Pulmonary Disease