What primarily causes COPD?

Chronic obstructive pulmonary disease (COPD) is primarily caused by long-term exposure to harmful substances that damage the lungs, with smoking being the most significant factor. Years of smoking introduce a variety of toxic chemicals and irritants into the respiratory system, leading to chronic inflammation, destruction of lung tissue, and impaired airflow. While other factors can contribute to the development of COPD, such as environmental pollutants and occupational exposure, smoking remains the foremost and most prevalent cause.

Viral infections and allergic reactions can lead to respiratory issues but do not primarily cause COPD. They might contribute to exacerbations or worsen the symptoms for someone who already has the disease. Genetic predisposition may play a role for some individuals, particularly those with a family history of lung disease or conditions like Alpha-1 antitrypsin deficiency, but smoking is overwhelmingly the primary risk factor in most cases of COPD.