According to a 10-year respiratory study reported in the first issue for January 2007 of the American Journal of Respiratory and Critical Care Medicine (published by the American Thoracic Society), young adults (ages 20 to 44) with normal lung function who later develop chronic cough and phlegm have four times higher risk of developing chronic obstructive pulmonary disease (COPD).

COPD is the fourth leading cause of death in the United States, killing 122,283 Americans in 2003. It results from chronic bronchitis and emphysema, two lung diseases which frequently co-exist and cause obstruction to airflow that interferes with normal breathing. Smoking is the primary cause of COPD.

Authors of the said study concluded that prevention of smoking and smoking cessation are the most effective strategies to minimize the occurrence of COPD.

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