What is the primary action of statins on cholesterol levels?

Statins primarily lower low-density lipoprotein (LDL) cholesterol levels in the body. They achieve this effect by inhibiting the enzyme HMG-CoA reductase, which is a key player in the cholesterol synthesis pathway in the liver. When this enzyme is blocked, the liver reduces its production of cholesterol. In response to the lower cholesterol levels, liver cells increase the uptake of LDL from the bloodstream, which helps to further decrease circulating LDL cholesterol levels. This reduction is crucial as high levels of LDL cholesterol are strongly associated with an increased risk of cardiovascular diseases, such as atherosclerosis and heart attacks.

While statins can also have positive effects on other lipid parameters, such as modestly increasing high-density lipoprotein (HDL) cholesterol and decreasing triglycerides, their primary objective and most clinically significant action is the reduction of LDL cholesterol. Therefore, the correct answer highlights the fundamental role of statins in managing cholesterol levels, particularly in patients at risk for cardiovascular events.