Obstructive lung disease makes breathing difficult and often gets progressively worse. People suffering from long-term coughing or mucus production may end up with chronic bronchitis. Destruction of the lung tissue over time causes emphysema. These two conditions are defined as chronic obstructive pulmonary disease or COPD, according to Medline Plus. Many people with COPD suffer from both chronic bronchitis and emphysema. A minority of people with asthma may develop COPD if chronic inflammation permanently restricts airflow.
Smoking
Smoking is the leading cause of COPD, Medline Plus points out. The more a person smokes the higher the risk of developing obstructive lung disease. Cigarette smoke causes more than 80 percent of chronic obstructive lung disease cases, according to the University of Maryland Medical Center (UMMC). Smoking results in inflammatory cells releasing chemicals in the deepest part of the lung affecting oxygen and carbon dioxide. Narrow tubes in lung tissue break away, causing holes and narrowing airways so it becomes difficult to breath. Lung function continues to get worse and risk of COPD greatly increases for people over age 50 who have smoked a pack a day for more than 20 years, the UMMC says.
Exposure
Exposure to heavy amounts of secondhand smoke and air pollution can contribute to lung disease, according to Medline Plus. People exposed to certain gases or fumes, environmental dust or organic materials in the workplace may also be at increased risk for developing obstructive lung disease. Frequently using cooking gas without proper ventilation may lead to lung disease. Some people may have abnormal sensitivities and exaggerated responses to inhaled substances, UpToDate notes.
Genetics
Genetic factors may be involved in obstructive lung disease because about 20 percent of people with COPD have never smoked, UpToDate points out. About a quarter of all smokers develop COPD, the UMMC says. A particular gene called ADAM33 is more common in smokers with COPD than smokers who do not have the disease. A small percentage of people with emphysema have an alpha-1 antitrypsin deficiency. The disorder prevents their bodies from making enough of a protective enzyme called AAT. As a result, damage occurs to air sacs in the lungs and the airways leading to them, the UMMC explains. Smokers with this deficiency have little chance of eluding emphysema and nonsmokers are at an increased risk of getting the disease. People with the deficiency can develop emphysema as young as age 30, the UMMC notes.
