McLaughlin 2005: TG/HDL Works Regardless of Body Weight

Background

Following their landmark 2003 study, the Stanford team led by Dr. McLaughlin asked an important follow-up question: does the TG/HDL ratio work only in overweight people, or is it a universal marker of insulin resistance?

This matters because metabolic dysfunction can occur at any body size. The "metabolically unhealthy normal weight" (MUNW) phenotype describes people with normal BMI who nevertheless have insulin resistance and elevated cardiovascular risk.

The Study

The researchers evaluated 449 healthy participants using the insulin suppression test (gold-standard for measuring insulin resistance) and analyzed LDL particle characteristics in 1,135 patients via gradient gel electrophoresis.

Key Findings

The results confirmed that TG/HDL ratio is a powerful metabolic marker:

• •Best predictor: The TG/HDL ratio was the single best predictor of both insulin resistance AND LDL particle diameter
• •Cutpoint of 3.5: A ratio ≥3.5 (mg/dL units) identified insulin-resistant patients with sensitivity and specificity comparable to full metabolic syndrome criteria
• •Small dense LDL: The ratio showed even greater sensitivity/specificity for detecting atherogenic small, dense LDL particles

Clinical Impact

This study has important implications for clinical practice:

1. •Simple screening tool: TG/HDL ratio from any standard lipid panel can identify metabolic dysfunction
2. •Beyond MetS criteria: The ratio performs as well as the complex 5-criterion metabolic syndrome definition
3. •Particle quality: Elevated ratio indicates not just metabolic dysfunction but also atherogenic LDL particle pattern

The findings emphasize that a single calculated ratio from routine blood work can identify high-risk patients who might otherwise be missed.