A group of metabolic risk factors linked to insulin resistance and associated with increased risk of cardiovascular disease. It is defined as the presence of any three of the following: 1) increased waist circumference (>102 cm for men, >88 cm for women), 2) elevated triglycerides >150 mg/dL, 3) low HDL cholesterol (less than 40 mg/dL for men, less than 50 mg/dL for women), 4) hypertension (systolic BP >130 and/or diastolic >85) or antihypertensive medication use, 5) impaired fasting glucose (>110 mg/dL). Syn: dysmetabolic syndrome, insulin resistance syndrome, metabolic syndrome X, syndrome X, visceral obesity syndrome.
The metabolic syndrome comprises several abnormalities, each an independent risk factor for cardiovascular disease, which have been associated on the premise of a unitary cause. The components of the syndrome are (1) insulin resistance manifested by fasting plasma glucose of 110 mg/dL (6.11 mmol/L) or higher, impaired glucose tolerance, and hyperinsulinemia (2) central obesity, defined as a waist circumference over 40 inches (102 cm) in men and over 35 inches (89 cm) in women; (3) systemic hypertension (systolic blood pressure over 130, diastolic pressure over 85); (4) high-density lipoprotein (HDL) cholesterol less than 40 mg/dL (1.03 mmol/L) in men and less than 50 mg/dL (1.29 mmol/L) in women; and (5) triglyceride 150 mg/dL (1.69 mmol/L) or more. For both men and women with all five of these stigmata, the risks of myocardial infarction and stroke are more than twice those of the general population. Additional features of the syndrome sometimes noted are high low-density lipoprotein (LDL) cholesterol, hyperuricemia, ovarian hyperproduction of androgen, and hypercoagulability of the blood. When the syndrome is defined as the presence of at least 3 of the 5 numbered disorders above, it is estimated to affect 23% of adults in the U.S. (approximately 47 million persons), including 10–15 million with type 2 diabetes mellitus (DM). It is particularly prevalent among non white populations in both developing and industrialized nations, and in those populations its prevalence is disproportionately high among children. The basis for the syndrome is genetic, and insulin resistance is considered the primary metabolic defect. There is considerable overlap between genetic pools of those with metabolic syndrome and of those with type 2 DM. Adoption of a sedentary lifestyle and development of obesity are believed to promote progression toward the fully developed syndrome and toward DM. The treatment of metabolic syndrome, directed at prevention of cardiovascular disease and of progression to type 2 DM, consists of aggressive efforts to identify patients so affected and to correct all metabolic abnormalities identified. Weight control by adoption of a low-calorie, low-cholesterol diet and regular aerobic exercise is essential. Hypertension and lipid abnormalities are corrected with pharmacologic agents.
Reference: Stedman's Medical Dictionary