The TG/HDL ratio compares triglyceride levels to HDL cholesterol. It is one of the simplest and most powerful surrogate markers for insulin resistance and atherogenic dyslipidaemia. When triglycerides are high and HDL is low — the classic metabolic syndrome pattern — the ratio rises and cardiovascular risk increases substantially.
A TG/HDL ratio below 1.0 (in mmol/L units) is considered optimal and is associated with predominantly large buoyant LDL particles (Pattern A). A ratio above 1.7–2.0 suggests insulin resistance and is associated with a shift toward the more dangerous small dense LDL Pattern B. The ratio above 2.0 strongly predicts the presence of small dense LDL even without measuring subfractions directly.
FAQs
How is the TG/HDL ratio calculated?
TG/HDL ratio = fasting triglycerides (mmol/L) divided by HDL cholesterol (mmol/L). It must be calculated from fasting samples as triglycerides rise after meals. Using mmol/L units, a ratio above 1.7 is concerning; using mg/dL units (as used in the US), the threshold is above 3.5.
Is the TG/HDL ratio as good as insulin resistance testing?
It is a practical surrogate. It does not directly measure insulin resistance but strongly correlates with insulin levels, HOMA-IR, and small dense LDL. It is clinically useful precisely because it is derived from the standard lipid panel without additional testing.
Can you have a good TG/HDL ratio but still have heart disease risk?
Yes. A low TG/HDL ratio does not exclude cardiovascular risk from elevated LDL, genetic factors, smoking, or hypertension. It is one useful risk indicator among many, particularly for atherogenic dyslipidaemia.
Does alcohol affect the TG/HDL ratio?
Complex effects. Moderate alcohol raises HDL, potentially improving the ratio. Heavy alcohol use raises triglycerides substantially, worsening it. Alcohol is not a recommended strategy for cardiovascular risk reduction.
