IDL (intermediate-density lipoprotein) particles form during the conversion of VLDL to LDL. They are atherogenic remnant lipoproteins that can be directly taken up by arterial walls. IDL is not captured by standard LDL tests and is underestimated in routine cardiovascular risk assessment.
Elevated IDL is particularly common in insulin resistance, metabolic syndrome, type III hyperlipoproteinaemia, and hypothyroidism. It represents atherogenic particle burden beyond what standard lipid panels detect.
FAQs
Is IDL included in standard LDL?
Standard LDL cholesterol partially includes IDL, but subfraction analysis quantifies IDL separately for more precise risk characterisation.
What is type III hyperlipoproteinaemia?
A genetic condition causing markedly elevated IDL and VLDL remnants due to impaired clearance. It causes premature cardiovascular disease and responds well to fibrate therapy.
How quickly can IDL improve?
Significant improvement can occur within 8-12 weeks of carbohydrate reduction, triglyceride lowering, and insulin sensitivity improvement.
Is IDL part of non-HDL cholesterol?
Yes. Non-HDL includes all atherogenic particles (LDL, VLDL, IDL, remnants). Elevated non-HDL with normal LDL may reflect elevated IDL.
