Chronic Obstructive Lung Disease - Risk Factors

Risk Factors

About 24 million people in the U.S. have COPD, although only half of them -- 12 million people -- have been diagnosed with the disease. Approximately 3.8 million people have emphysema. Because emphysema and chronic bronchitis so often occur together, it is difficult to determine the number of emphysema patients versus those with chronic bronchitis. Many patients, even if their symptoms are severe, regard their condition as a natural part of aging, or blame a lack of fitness, and do not get examined by a health care provider.

The main risk factors for COPD include:

• Cigarette smoke
• Age older than 40 years
• Exposure to occupational dust and chemicals
• Exposure to smoke from wood or other biomass fires
• Exposure to indoor air pollution
• Alpha-1 antitrypsin deficiency

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Occupational Risk Factors

Workers who are exposed for a long time to toxic chemicals (such as silica or cadmium), industrial smoke, dust, or other air pollutants are at increased risk for COPD. Such workers include:

• Cooks
• Furnace workers
• Grain farmers
• Miners
• Women who cook over open fires
• Railroad workers (from exposure to diesel exhaust)

Allergies and Asthma

Allergens are allergy-causing particles and organisms such as fungi, molds, and house dust. The connection between allergies, asthma, and COPD is the topic of much debate. Some physicians believe allergies and asthma are early stages of COPD. Another school of thought says that COPD causes changes to the airways that produce asthma symptoms.

Although the exact connection is not known, patients with hyperactive airways due to allergies or asthma are at increased risk for COPD. Patients with COPD who can control their airway problems with bronchodilators (the medication used in asthma) are less likely to die from COPD.

HIV

People infected with HIV are 50% - 60% more likely to develop COPD than people who do not have HIV. The percentage of HIV patients who smoke is not much larger than those who do not smoke. This suggests that HIV increases susceptibility to COPD or speeds up the decline in lung function.

Other Risks

Abnormal lung development in the womb might increase the risk for COPD later in life. Researchers have found that newborns with poor airway function are more likely to have breathing disorders as adults. Preventive measures for these children might need to start in infancy.

Research also finds that eating bacon, sausage, and other cured meats might reduce lung function and increase the risk for COPD. Cured meats are high in nitrates, which act much like tobacco smoke to damage the lungs, according to researchers.

Review Date: 04/10/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org).