What is the primary cause of chronic obstructive pulmonary disease (COPD)?

Cigarette smoking is recognized as the primary cause of chronic obstructive pulmonary disease (COPD). It is responsible for the majority of cases and is linked to the inflammatory response it triggers in the lungs. The harmful substances in cigarette smoke lead to chronic inflammation, which causes damage to the airways and lung tissue over time. This damage results in the progressive airflow limitation characteristic of COPD, along with the development of chronic bronchitis and emphysema, which are two key components of the disease.

While environmental pollutants, chronic asthma, and respiratory infections can contribute to respiratory issues and exacerbate COPD, they are not considered the primary cause. Environmental pollutants can aggravate existing conditions, chronic asthma is a different disease process that can lead to other complications but is not a direct cause of COPD, and respiratory infections can result in acute exacerbations but do not initiate the underlying pathology of COPD. Thus, cigarette smoking's direct role in causing repeated injury to lung tissue solidifies its status as the primary cause of COPD.