Cholesterol

Cholesterol is a waxy, fat-like substance present in every cell of the body — essential for producing cell membranes, steroid hormones (cortisol, sex hormones), vitamin D, and bile acids for digestion. It is carried in the blood by lipoprotein particles: LDL (low-density lipoprotein — 'bad cholesterol') deposits cholesterol in arterial walls contributing to atherosclerosis, while HDL (high-density lipoprotein — 'good cholesterol') removes cholesterol from arteries back to the liver for disposal.

Cholesterol is measured through a fasting lipid profile (fasting blood test): total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. The key target varies by cardiovascular risk — for most adults, LDL <3.0 mmol/L is recommended; for those with established cardiovascular disease or diabetes, LDL <1.8 mmol/L (or <1.4 mmol/L for very high-risk patients) using high-intensity statin therapy. Triglycerides above 5.6 mmol/L indicate high risk of pancreatitis.

Cholesterol-lowering strategies include lifestyle measures (reduced saturated fat, increased soluble fibre, Mediterranean diet, exercise, smoking cessation) and medication — statins are the cornerstone pharmacological treatment. In Korea, routine cholesterol screening is part of the National Health Insurance Service (NHIS) biennial adult health checks, and lipid management is a key component of cardiovascular disease prevention programmes.