Causes, Development & Risk Factors of Emphysema

It is known from scientific research that the normal lung has a remarkable balance between two classes of chemicals with opposing action. The lung also has a system of elastic fibers. The fibers allow the lungs to expand and contract. When the chemical balance is altered, the lungs lose the ability to protect themselves against the destruction of these elastic fibers. This is what happens in emphysema.

There are a number of reasons this chemical imbalance occurs. Smoking is responsible for 82% of chronic lung disease, including emphysema. Exposure to air pollution is one suspected cause. Irritating fumes and dusts on the job also are thought to be a factor.

A small number of people with emphysema have a rare inherited form of the disease called alpha I-antitrypsin (AAT) deficiency-related emphysema, or early onset emphysema. This form of disease is caused by an inherited lack of a protective protein called alpha I-antitrypsin (AAT).

How Does Emphysema Develop?

Emphysema begins with the destruction of air sacs (alveoli) in the lungs where oxygen from the air is exchanged for carbon dioxide in the blood. The walls of the air sacs are thin and fragile. Damage to the air sacs is irreversible and results in permanent "holes" in the tissues of the lower lungs. As air sacs are destroyed, the lungs are able to transfer less and less oxygen to the bloodstream, causing shortness of breath. The lungs also lose their elasticity. The patient experiences great difficulty exhaling.

Emphysema doesn't develop suddenly, it comes on very slowly. Years of exposure to the irritation of cigarette smoke usually precede the development of emphysema. A person may initially visit the doctor because they start to feel short of breath during activity or exercise. As the disease progresses, a short walk can be enough to bring on breathing difficulty. Some people may have chronic bronchitis before developing emphysema.

Risk Factors for Emphysema

By far, the single greatest risk factor for emphysema is smoking. Emphysema is most likely to develop in cigarette smokers, but cigar and pipe smokers also are susceptible, and the risk for all types of smokers increases with the number of years and amount of tobacco smoked. Men are affected more often than women are, but this statistic is changing as more women take up smoking. Second-hand smoke can also cause emphysema and lung disease.

Other risk factors include:

• Age. Although the lung damage occurring with emphysema develops gradually over time, most people with tobacco-related emphysema begin to experience symptoms of the disease between the ages of 50 and 60.
• Exposure to second-hand smoke. Secondhand smoke, also known as passive or environmental tobacco smoke, is smoke that you inadvertently inhale from someone else's cigarette, pipe or cigar.
• Occupational exposure to chemical fumes. If you breathe fumes from certain chemicals or dust from grain, cotton, wood or mining products, you're more likely to develop emphysema. The risk is even greater if you smoke.
• Exposure to indoor and outdoor pollution. Breathing indoor pollutants such as fumes from heating fuel as well as outdoor pollutants — car exhaust, for instance — increases your risk of emphysema.
• Heredity. A rare, inherited deficiency of the protein, alpha-1-antitrypsin (AAt) can cause emphysema, especially before age 50, and even earlier if you smoke.
• HIV infection. Smokers living with HIV are at greater risk of emphysema — and of developing the disease at a relatively young age — than are smokers who don't have HIV infection.
• Connective tissue disorders. Some conditions that affect connective tissue — the fibers which provide the framework and support for your body — are associated with emphysema. These conditions include cutis laxa, a rare disease that causes premature aging, and Marfan syndrome, a disorder affecting many different body organs, especially the heart, eyes, skeleton and lungs.