Which condition is chronic obstructive pulmonary disease (COPD) primarily associated with?

Chronic obstructive pulmonary disease (COPD) is primarily characterized by blocked airflow and difficulty breathing. This condition involves progressive restrictions in airflow, making it harder for individuals to exhale air from their lungs. As a result, patients may experience symptoms such as chronic cough, wheezing, and increased breathlessness, particularly during physical activity. The airflow obstruction in COPD is usually caused by long-term exposure to irritants, such as cigarette smoke or air pollution, that damage the lungs and airways over time.

The other options may relate to broader health issues but do not specifically define COPD. For instance, while inflammation of the immune system can contribute to various respiratory diseases, it is not the defining characteristic of COPD. Similarly, although COPD can increase susceptibility to respiratory infections, the primary issue at hand is the obstructed airflow and subsequent breathing difficulties. Lastly, while COPD can indeed have secondary effects on the circulatory system, particularly in advanced stages, it is not primarily classified as a circulatory issue, so that option does not correctly capture the essence of COPD.