The following factors may cause carotid intima-media thickening: 1) Age, which usually causes gradual thickening of the carotid intima-media with age, and a weakening of the elasticity and brittleness of the carotid intima-media. 2) Carotid intima-media thickening is also directly related to hyperlipidemia in the body, such as high cholesterol levels and high LDL levels in the blood, which may also lead to atherosclerosis and plaque formation in the carotid arteries. 3. Some hypertensive factors may also lead to thickening of the intima in the arteries. 4. Some patients with high blood viscosity may also experience thickening of the carotid artery intima.