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Metabolic syndrome
Which of the following is one of the diagnostic criteria for the metabolic syndrome under the NCEP ATP III definition?
- correctA. Fasting triglycerides of 150 mg/dL or more
- B. Total cholesterol of 200 mg/dL or more
- C. Serum uric acid above the upper limit of normal
- D. LDL cholesterol of 130 mg/dL or more
Explanation
Key fact
LDL is not a criterion for the metabolic syndrome. The lipid abnormalities that count are high triglycerides and low HDL.
Fasting triglycerides of 150 mg/dL or more. Any three of the five criteria make the diagnosis.
Why
The syndrome describes the consequences of insulin resistance.
Insulin resistance raises triglycerides and lowers HDL - the atherogenic dyslipidaemia.
It does not characteristically raise LDL, which is why LDL is excluded.
The other criteria are central obesity, raised blood pressure and raised fasting glucose.
Any three of the five are sufficient.
The five NCEP ATP III criteria
| Criterion | Threshold |
|---|---|
| Waist circumference | Over 102 cm in men, 88 cm in women (lower cut-offs in Asians) |
| Fasting triglycerides | 150 mg/dL or more |
| HDL cholesterol | Under 40 mg/dL in men, under 50 in women |
| Blood pressure | 130/85 mmHg or more, or on treatment |
| Fasting glucose | 100 mg/dL or more, or on treatment |
Any three of five, and LDL is not one of them
Why not the others
- B. Total cholesterol of 200 mg/dL or more — is likewise not one of the five criteria.
- C. Serum uric acid above the upper limit of normal — is associated with insulin resistance but is not a diagnostic criterion.
- D. LDL cholesterol of 130 mg/dL or more — is a cardiovascular risk factor and a treatment target, but it is not part of the metabolic syndrome definition.
Remember
Waist, triglycerides, HDL, blood pressure, glucose - any three. LDL is the famous absentee.
Go deeper
Asian cut-offs are lower - about 90 cm in men and 80 cm in women - because cardiometabolic risk rises at a smaller waist in South Asians.
Acanthosis nigricans, the velvety dark thickening at the neck and axillae, is a visible marker of insulin resistance and should prompt screening.
Management is weight loss and exercise first; there is no drug for the syndrome itself, only for its components.
Harrison's Principles of Internal Medicine, 22nd ed. (McGraw Hill, 2025).