Small, Dense LDL: The Risk Your Usual Cholesterol Number Hides

The Big News

A massive UK study (over 270,000 people, ~10 years) shows a specific type of “bad” cholesterol—small, dense LDL—predicts heart risk better than the standard LDL number. The estimate is called E‑sdLDL‑C (estimated small, dense LDL cholesterol). It can be calculated from your regular blood test.

Why You Should Care

• Your LDL‑C might look “fine” while risk is still high.
• E‑sdLDL‑C catches hidden risk that LDL‑C misses.
• If E‑sdLDL‑C is high—even when LDL‑C or ApoB (particle number) look okay—your risk goes up.

Key Findings (Plain English)

• Higher E‑sdLDL‑C = higher heart disease risk.
• This stayed true after accounting for age, blood pressure, diabetes, and meds.
• When E‑sdLDL‑C was higher than LDL‑C or ApoB, risk jumped (about 31% vs LDL‑C; 17% vs ApoB).
• Once ApoB was considered, LDL‑C became misleading—E‑sdLDL‑C still signaled danger.

How to Check Your Own Results

You don’t need a new test—E‑sdLDL‑C can be calculated from your usual panel. Two simple flags point to more small, dense LDL:

• Triglycerides high: - ≥150 mg/dL or ≥1.7 mmol/L

• HDL‑C low: - Men: <40 mg/dL or <1.0 mmol/L - Women: <50 mg/dL or <1.3 mmol/L

If your lab reports E‑sdLDL‑C, great—use that number (mg/dL or mmol/L). If not, use the pattern above as a practical proxy.

“Discordance” matters:

• If E‑sdLDL‑C (or the high‑triglyceride/low‑HDL pattern) is high while LDL‑C looks fine, treat that as higher risk.

Bottom Line

Your standard LDL number can be flattering. Small, dense LDL tells the truth. If triglycerides are high and HDL‑C is low—or your E‑sdLDL‑C is elevated—don’t ignore it.