METABOLIC SYNDROME: HOW TO DEFINE HEALTH RISKS
In 1988, at the Banting Lecture at the annual meeting of the American Diabetes Association,1 Dr. Gerald Reaven of Stanford University described a constellation of metabolic abnormalities associated with an increased risk for diabetes and atherosclerotic cardiovascular disease (CVD). This cluster of risk factors was designated “syndrome X,” or insulin resistance syndrome. Dr. Reaven stated that persons with syndrome X2 manifest glucose intolerance, dyslipidemia, abnormal uric acid metabolism, renal salt retention, increased sympathetic tone, and hypercoagulability due to increases in plasminogen activator inhibitor 1 (PAI-1).
As the defining features of syndrome X have evolved, researchers coined the term metabolic syndrome (metS) to describe the abnormalities that identify the segment of the population at risk for diabetes and atherosclerotic disease. But, there has been a lack of consensus on a precise definition of metS.
The World Health Organization, National Cholesterol Education Project, American Academy of Clinical Endocrinology, and International Diabetes Federation have published somewhat different diagnostic criteria (Table 29-1). Consequently, the National Heart, Lung, and Blood Institute and the American Heart Association in 2004 convened a conference to develop a meaningful definition of metabolic syndrome.3 Clinical features they agreed on include the following:
TABLE 29-1Metabolic Syndrome: Varying Definitions |Favorite Table|Download (.pdf) TABLE 29-1 Metabolic Syndrome: Varying Definitions
| ||Blood Pressure ||Lipids ||Central Obesity ||Glucose ||Other ||Diagnostic Requirements |
|WHO ||On antihypertensive therapy or BP ≥ 140/90 mm Hg ||Plasma triglycerides over 150 dL/mL and/or HDL-C < 35 mg/dL (men), < 39 mg/dL for women ||BMI > 30 and/or waist-hip ratio > 0.9 (men), > 0.85 (women) ||IGT or as in type 2 diabetes ||Microalbuminuria (UAE ≥ 20 μg/min or albumin-creatinine ratio ≥ 30 mg/g) ||Type 2 diabetes or IGT and 2 additional abnormalities; if GT normal, 3 required |
|NCEP ATP III ||BP ≥ 130/85 mm Hg ||Plasma triglycerides over 150 dL/mL and/or HDL-C < 40 mg/dL (men), < 50 mg/dL for women ||Waist circumference > 102 cm (40 in.) (men), > 88 cm (35 in.) (women) ||FBG ≥ 110 mg/dL || ||3 or more of criteria listed |
|AACE ||Hypertension ||Plasma triglycerides over 150 dL/mL and/or HDL-C <35 mg/dL (men), <45 mg/dL for women ||Waist circumference > 102 cm (40 in.) (men), >88 cm (35 in.) (women) ||IFG or as in type 2 diabetes || |
Insulin resistance, acanthosis nigricans, hyperuricemia.
Minor criteria: hypercoagulability, coronary heart disease, polycystic ovarian disease, vascular endothelial dysfunction, microalbumenuria
|Not specified |
Abdominal obesity is the form of obesity most strongly associated with metS. It presents clinically as increased waist circumference.
Atherogenic dyslipidemia manifests in routine lipoprotein analysis by raised triglycerides and low concentrations of high-density lipoprotein (HDL) cholesterol and many times other lipoprotein abnormalities (e.g., increased remnant lipoproteins, elevated apolipoprotein B, small low-density lipoprotein [LDL] particles, and small HDL particles). All of these abnormalities have been implicated as ...