A risk factor is something that increases your likelihood of getting a disease or condition.

It is possible to develop COPD with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing COPD. If you have a number of risk factors, ask your healthcare provider what you can do to reduce your risk.

Risk factors include:

Cigarette Smoking

The most important risk factor for COPD is cigarette smoking. Between 80% and 90% of COPD cases are caused by cigarette smoking. Although most cases of COPD are related to smoking, not all smokers develop COPD. This suggests that other factors in your environment or genetic make-up also contribute to the development of COPD. New research also suggests that people who are chronically exposed to second-hand smoke have an increased risk of developing COPD.

Genetic Factors

Although COPD usually develops in older persons with a long history of cigarette smoking, one form of emphysema has a genetic component, runs in families, and is more common in persons of northern European descent. Persons with this form of COPD have a hereditary deficiency of a blood component, known as alpha-1-protease inhibitor (alpha-1-antitrypsin, AAT). About 70,000 Americans are thought to have this genetic deficiency, and it accounts for 1%-3% of COPD cases. People with this defect can develop COPD by early middle age. If you have close relatives who developed COPD in their thirties or forties, your risk of this type of COPD may be elevated. A deficiency of AAT can be detected by blood tests available at medical laboratories.


You are more likely to develop COPD as you get older, but this is partly related to the number of years of cigarette smoking.

Medical Conditions

A history of frequent childhood lung infections increases your risk of developing COPD. Frequent infections can lead to scarring of lung tissues, which reduces their elasticity and can lead to COPD.


COPD is much more common in men than in women, but this may be largely related to the higher rate of smoking among men. As the number of women who have significant smoking histories has increased, the number of COPD-related deaths among women has also risen.

Ethnic Background

COPD is more common in whites, despite high rates of smoking among blacks and other racial and ethnic groups. This suggests that genetic factors that increase the risk of COPD may be more common in whites than in other racial and ethnics groups.

Exposure to Environmental and Occupational Pollutants

Chronic exposure to dust, ozone, and gases or chemicals, such as traffic exhaust fumes and sulfur dioxide, increase your risk of developing COPD and can worsen symptoms of the disease. Although second-hand smoke has not been found to increase the risk of COPD, it can cause other problems and should be avoided.