Smoking causes free-radical damage. In the arteries this damage triggers the immune system and inflammation pathways. Macrophages appear at the sites of the arteries that are damaged. They combine with the fatty streaks in our arteries and then trap minerals such as calcium along with LDL. So LDL is trapped and this signals the body to produce more. This blockage becomes hard and restricts our arteries. Smoking creates an environment in the bloodstream that leads to a destructive breakdown [of cholesterol], making LDL even more toxic to blood vessels, increasing deposits of plaque in the arteries, and increasing inflammation. At the same time good cholesterol, HDL, is lowered and triglycerides are raised. However, the main damage of burden of smoking is atherosclerosis which leads to blood clots breaking off causing stroke and heart attacks. Second-hand smoke is associated with increased mitochondrial damage in cardiovascular tissues. "Tobacco smoke exposure also resulted in significantly decreased specific activities of mitochondrial enzymes. The combination of secondhand smoke and hypercholesterolemia resulted in increased atherosclerotic lesion formation and even greater levels of mitochondrial damage". Below is an article about cigarette smoke and high serum cholesterol.

Thank you Prof. Joan Vaccaro

At leasr in my experience, smoking does not raise LDL-c , but it can lower HDL-c, due to peripheral vasospasm, which prevents remnant particles from being metabolized by LPL.

Yes, lower HDL which indirectly leads to atherosclerosis. Raising LDL has not been ruled out, but it has not been established.

Smoking contributes to atherosclerosis by increasing small-dense LDL-C and decreasing HDL-C (1-2)

Therefore, smoking works by adding petrol to the fire.

1. Article Relationship between smoking and dyslipidemia in western Chi...

2. Article Smoking and Small, Dense Low-Density Lipoprotein Particles: ...

Thank you Prof. William Feeman, Joan Vaccaro, Muhammad Yousuf

You are welcome!

Please also have a look at this:

Article Acrolein Impairs the Cholesterol Transport Functions of High...

Thank you Prof. Arvind Singh