In which way does cigarette smoking primarily increase the risk of stroke?

In which way does cigarette smoking primarily increase the risk of stroke?

• A. by decreasing platelet adhesion, which impairs the ability of red blood cells to clot
• B. by increasing the levels of high-density lipoproteins (HDLs), which allow fatty tissue to build up in arteries
• C. by reducing the rate of oxygen delivered to the heart, thereby promoting the formation of free radicals
• D. by raising blood pressure, which increases stress on blood vessel walls, making them more likely to burst

Answer: (D)

Smoking raises blood pressure by stimulating the sympathetic nervous system and causing blood vessels to constrict. That extra pressure stresses artery walls, making rupture more likely and increasing the risk of a hemorrhagic stroke. While smoking also accelerates atherosclerosis and clot formation, which raises ischemic stroke risk, the direct and primary effect described here is the rise in blood pressure. The other statements don’t fit: smoking does not decrease platelet adhesion (it increases platelet activation and clotting), it lowers HDL (not increases it), and although it can impair oxygen delivery and cause oxidative stress, that isn’t the main mechanism for stroke risk highlighted in this item.

Smoking raises blood pressure by stimulating the sympathetic nervous system and causing blood vessels to constrict. That extra pressure stresses artery walls, making rupture more likely and increasing the risk of a hemorrhagic stroke. While smoking also accelerates atherosclerosis and clot formation, which raises ischemic stroke risk, the direct and primary effect described here is the rise in blood pressure. The other statements don’t fit: smoking does not decrease platelet adhesion (it increases platelet activation and clotting), it lowers HDL (not increases it), and although it can impair oxygen delivery and cause oxidative stress, that isn’t the main mechanism for stroke risk highlighted in this item.