Official Metabolic Syndrome Definition

There are several "official" definitions of the metabolic syndrome (insulin resistance syndrome). These description come from the criteria of the World Health Organization (WHO), the American Association of Clinical Endocrinologists (AACE), and other information from the American Heart Association.

1. Signs of Insulin Resistance

Some signs of insulin resistance are:

• Impaired fasting blood glucose (the American Diabetes Association considers the cutoff to be 100 mg/dL)
• Impaired glucose tolerance (blood glucose above 140 two hours after a 75g glucose challenge)
• A diagnosis of Type 2 diabetes is automatically included

The problem with using only these criteria is that they only address insulin resistance which has progressed so far that the individual has become prediabetic. It is well known that there is a phase before this where the person is insulin resistant, but their body is dealing with it by putting out larger amounts of insulin (hyperinsulinemia). In my opinion, insulin resistance should be addressed before glucose tolerance begins to fail.

The only group which addresses this is WHO, which adds the following: "or for those with normal fasting glucose levels, glucose uptake below the lowest quartile for background population under investigation under hyperinsulinemic, euglycemic conditions". The problem with this is that glucose uptake is not a normal screening test.

2. Other Signs of Metabolic Syndrome

WHO Criteria - the World Health Organization bases it's definition on the above, plus two of the following:

• High blood pressure (>=140 mm Hg systolic or >=90 mm Hg diastolic) or taking blood pressure medication
• Plasma triglycerides >=150 mg/dL (>=1.7 mmol/L)
• HDL cholesterol <35 mg/dL (<0.9 mmol/L) in men or <39 mg/dL (1.0 mmol/L) in women
• BMI greater than 30 and/or waist:hip ratio >0.9 in men, >0.85 in women
• Urinary albumin excretion rate >=20 µg/min or albumin:creatinine ratio >=30 mg/g

American Association of Clinical Endocrinologists criteria are similar, but with some different cutoffs.:

• High blood pressure (>=130 mm Hg systolic or >=85 mm Hg diastolic) or taking blood pressure medication
• Plasma triglycerides >=150 mg/dL (>=1.7 mmol/L)
• HDL cholesterol <40 mg/dL (<0.9 mmol/L) in men or <50 mg/dL (1.0 mmol/L) in women
• BMI greater than 25
  Other risk factors including:
• Family history of Type 2 diabetes, high blood pressure, or heart disease
• Ethnic groups with an increased incidence of Type 2 diabetes, high blood pressure, or heart disease
• Polycystic ovary syndrome
• Sedentary lifestyle
• Advancing age

The American Heart Association says agrees with AACE, but adds waist circumference of more than 102 cm (>40 in) in men and 88 cm (>35 in) for women.

Reference:

Grundy, Scott, et al "Definition of Metabolic Syndrome." Circulation 109 (2004): 433-438.