Risk Factors

Risk Factors

As of 2003, 10.7 million adults were diagnosed with chronic obstructive lung disease, 2.1 million of them people with 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. Experts estimate, however, that more than half of Americans with impaired lung function go undiagnosed. Many patients, even if their symptoms are severe, regard their condition as a natural part of aging, or blame lack of fitness, and fail to seek medical evaluation.

General Risk Factors for Chronic Obstructive Lung Disease

The typical COLD patient is a smoker or ex-smoker, with a pack-a-day habit of more than 20 years, who is over 50. Lung function gets worse as people get older.

According to a major 2002 government report, since 1987 more women than men have reported symptoms of COLD. Furthermore, the death rate from COLD has increased dramatically in women since the early 1970s. In 2000, the number of women who died from these lung diseases surpassed the number of men who died of the same causes. The lungs of female smokers, moreover, appear to be more susceptible to the effects of smoking and pollution than those of men. Studies suggest that COLD is underdiagnosed in both genders, but especially in women. Caucasians are more susceptible to emphysema than African Americans.

On the positive side, the proportion of adults under 55 who are diagnosed with mild to moderate COLD has been declining, indicating that the high death rate will level out, especially as more people stop smoking. In particular, the rate of COLD in young African Americans is declining significantly. The rate in younger Caucasians is not decreasing as dramatically.

Smoking

Over 80% of people who die from COLD are or were smokers. The longer a person smokes, the higher the risk for emphysema. Once a smoker quits, the rate of lung function loss becomes the same as in a nonsmoker; however, much of the lung damage incurred during smoking may be irreversible. About 10% to 20% of people who smoke more than one pack a day develop significant airway obstruction, so other factors must be present.

Occupational Risk Factors

Workers 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 COLD. Such workers include miners, furnace workers, grain farmers, cooks, and other food producers who work in small spaces.

Allergies and Asthma

Allergens are allergy-causing particles and organisms such as fungi, molds, and house dust. Allergens can cause changes in the lungs that lead to COLD in some people. Some experts believe that a susceptibility to allergens or asthma puts smokers at higher risk for COLD.

Dietary Factors

Some evidence indicates that poor nutrition, particularly low levels or lack of certain nutrients (e.g., vitamins A, C, and E), could increase the risk for impaired lung function. Fresh fruits and vegetables, nuts, and whole grains are a good source of such nutrients.

Low Birth Weight

Low birth weight is associated with increased risk for COLD in later life, perhaps because poor nutrition during a fetus's development may lead to smaller, ill-functioning lungs.

Periodontal Disease

In a 2001 study, patients with periodontal (gum) disease had one and a half times the risk for COLD as those without gum disease. Experts speculate that the bacteria causing periodontal disease could theoretically travel through saliva or breath into the lungs. The bacteria in periodontal disease also cause inflammation, which may also affect the linings of the airway.