How does smoking contribute to cardiovascular diseases?

Smoking contributes to cardiovascular diseases primarily by causing inflammation and damage to blood vessels. When a person smokes, the harmful chemicals in tobacco smoke damage the lining of the blood vessels. This damage can lead to atherosclerosis, a condition where plaque builds up in the arteries, causing them to become narrow and harden. Such changes increase the risk of heart attacks and strokes.

In addition to direct damage, smoking also promotes inflammatory processes within the body. This inflammation can further exacerbate the damage to blood vessels, leading to chronic health issues over time. Furthermore, smoking affects the balance of blood clotting factors, which can lead to thrombus formation (blood clots) and increase the risk of vascular events.

While the other options suggest mechanisms that could be beneficial to cardiovascular health—like increased oxygen levels, better circulation, or lowered cholesterol—none of these accurately reflect the impact of smoking. In fact, smoking is associated with detrimental health issues, including reduced oxygen delivery to tissues, impaired circulation, and often increased cholesterol levels rather than decreased.