HDL cholesterol

HDL cholesterol (high-density lipoprotein cholesterol) measures the cholesterol carried by HDL particles, which transport cholesterol from tissues back to the liver in reverse cholesterol transport. Population studies historically associated higher HDL-C with lower cardiovascular risk, but Mendelian randomization and HDL-raising drug trials show the relationship is non-causal and U-shaped: very high HDL-C is also linked to increased mortality. HDL functionality matters more than its concentration alone.