Metabolic Syndrome Calculator — South Asian Waist Cut-offs

Metabolic syndrome is not one disease but a cluster of five risk factors that, together, sharply raise the odds of type-2 diabetes and cardiovascular disease. This tool applies the 2009 Harmonized (IDF/NCEP) definition — the current international standard, published as a Joint Interim Statement by the IDF, NHLBI, AHA, World Heart Federation and others in Circulation (2009). The rule is deliberately simple: metabolic syndrome is present when any 3 of the 5 criteria are met.

1. Elevated waist circumference — population-specific. For South Asians, including Sri Lankans, the IDF cut-off is ≥ 90 cm for men and ≥ 80 cm for women — lower than the 94/80 cm European numbers.
2. Elevated triglycerides — ≥ 150 mg/dL (1.7 mmol/L), or on drug treatment for high triglycerides.
3. Reduced HDL cholesterol — < 40 mg/dL in men, < 50 mg/dLin women, or on lipid drug treatment. (Note the strict “less than”: exactly 40 in a man is not met.)
4. Elevated blood pressure — systolic ≥ 130 and/or diastolic ≥ 85 mmHg, or on antihypertensive treatment.
5. Elevated fasting glucose — ≥ 100 mg/dL (5.6 mmol/L), or on glucose-lowering treatment.

There are no fitted coefficients or probabilities here — every threshold is a published constant. When you enter values in mmol/L, the tool converts them to mg/dL first using the standard factors (glucose ×18.0, triglycerides ×88.57, HDL ×38.67) before comparing against the thresholds. The “on drug treatment” checkboxes exist because the 2009 statement counts a treated component as met regardless of the current reading — a person controlled on medication still carries the underlying abnormality. The single most common mistake in global calculators is applying the Western 94 cm male waist cut-off to South Asian users, which under-counts central obesity; this tool uses the 90/80 cm figures by default. To guard against unit-conversion bugs, the result is independently recounted in the entered unit and the two counts must agree.

• Alberti et al. — Harmonizing the Metabolic Syndrome (Circulation, 2009): the 3-of-5 rule and TG/HDL/BP/glucose thresholds
• IDF Consensus Worldwide Definition of the Metabolic Syndrome (2006): South Asian waist cut-offs (men ≥ 90 cm, women ≥ 80 cm)
• Grundy et al. — Diagnosis and Management of the Metabolic Syndrome, AHA/NHLBI (Circulation, 2005): original NCEP ATP III components

Thresholds and cut-offs on this page were last cross-checked against the cited sources on 2026-07-17. They are reviewed whenever the governing consensus statements are updated.