Lifestyle choices such as cigarette smoking have long been thought to be the primary cause of chronic obstructive pulmonary disease (COPD), but a new study indicates that genetics may also play a role.
The study was conducted to answer the question of why some smokers don’t develop COPD while many non-smokers do, and to fully understand the pathogenesis of this disease, which affects more than 16 million Americans.
COPD is a progressive lung disease that encompasses both emphysema and chronic bronchitis. It is the fourth leading cause of death in the U.S., but has never been fully understood. The belief has been that COPD develops in later years after a lifetime of exposure to cigarette smoke or other harmful chemicals. But prevalence among non-smokers and recent studies that have shown poor lung function in younger individuals led this research team to find that nearly a quarter of adults have physical lung variations that may increase their risk of developing COPD.
The study was funded by the National Heart, Lung and Blood Institute (NHLBI) and published in Proceedings of the National Academy of Sciences. Led by a team at the Columbia University Medical Center, researchers found that a genetic variation in the standard branching patterns of the airway tree—including bronchial tubes, bronchioles, and alveoli—may also be to blame for the development of COPD. Autopsy findings referenced in the study indicate variations in the branching patterns may play a role in the development of COPD, and these deviations from the standard pattern can affect 1 in 4 people.
The research team went on to study the CT scans of 3,000 adults aged 60 to 78, about half of which were current or former smokers. They found that 6% were missing a branch of the airway tree in the lower section, 16% had an extra branch, and 4% had some other deviation from the standard pattern.