1.18—Cholesterol, HDL, LDL and CVD evidence

Cholesterol is transported in the blood in lipoproteins. LDL carries cholesterol towards tissues and is associated with atheroma risk when present in excess; HDL participates in reverse transport towards the liver.

A measured concentration is one risk indicator among many. Age, blood pressure, smoking, diabetes, genetics and treatment all affect the probability of CVD, and the relationship is population-based rather than deterministic.

Two people with the same LDL concentration can have different overall risk because their blood pressure, smoking status and family history differ. A treatment decision therefore uses a risk profile, not one number alone.

When interpreting data, identify the population, units, time period and whether the result is correlation or an intervention effect. Check uncertainty before claiming that changing one lipoprotein will remove risk.

HDL is not a guarantee of protection and LDL is not a diagnosis by itself. Avoid turning a continuous risk relationship into a binary label.