因為很多人在有高膽固醇的同時還有代謝綜合症（metabolic syndrome）。

Metabolic syndrome is also known as metabolic syndrome X, syndrome X, insulin resistance syndrome.

WHO's definition for metabolic syndrome X

The World Health Organization criteria (1999) require presence of one of diabetes mellitus, impaired glucose tolerance, impaired fasting glucose or insulin resistance, AND two of the following:

• Blood pressure: ≥ 140/90 mmHg
• Dyslipidemia: triglycerides (TG): ≥ 1.695 mmol/L and high-density lipoprotein cholesterol (HDL-C) ≤ 0.9 mmol/L (male), ≤ 1.0 mmol/L (female)
• Central obesity: waist:hip ratio > 0.90 (male); > 0.85 (female), or body mass index > 30 kg/m²
• Microalbuminuria: urinary albumin excretion ratio ≥ 20 µg/min or albumin:creatinine ratio ≥ 30 mg/g