What is the most common cause of an aneurysm?

The most common cause of an aneurysm is associated with arteriosclerosis. Arteriosclerosis refers to the thickening and hardening of the arterial walls due to the buildup of fatty deposits, cholesterol, and other substances, which ultimately leads to the narrowing of arteries. As the arteries become less flexible and stiffer, they are more prone to developing aneurysms, where a bulge forms in the weakened area of an artery. This process is typically progressive and is particularly influenced by factors such as high cholesterol levels, diabetes, and aging.

While hypertension and genetic predisposition can contribute to the development of aneurysms, they are often secondary to the changes brought on by arteriosclerosis. Infection can lead to aneurysms in rare cases, particularly mycotic aneurysms, but this is significantly less common than complications arising from arteriosclerosis.