Metabolic Syndrome X

Please find below the definition and the NLA approach to Metabolic Syndrome. MS or Syndrome X is a significant contributor to cardiovascular disease and type 2 diabetes. Its prevalence often parallels obesity epidemic. 

Guidelines were published in April 2015. Text has been slightly modified for easier and succinct reading.


J of Clinical Lipidology


April 2015

Metabolic syndrome is recognized as a multiplex risk factor for both ASCVD and type 2 diabetes mellitus. Available evidence from meta-analyses suggests that metabolic syndrome is independently associated with ASCVD risk, essentially doubling the risk. The increased ASCVD risk with metabolic syndrome is generally considered to be above and beyond that associated with traditional ASCVD risk factors; the predictive value of metabolic syndrome for type 2 diabetes mellitus risk, although substantial, is less than that shown for diabetes-specific risk equations.

Increased adiposity and insulin resistance appear to be central pathophysiological features of this cluster of interrelated metabolic and hemodynamic disturbances including elevations in blood pressure, triglycerides and glucose, as well as depressed HDL. The metabolic syndrome also likely reflects ASCVD risk secondary to indicators that are often not measured clinically including increased oxidation, inflammation, endothelial dysfunction, and thrombogenicity. Some of the NLA Expert Panel members were in favor of recommending that a diagnosis of metabolic syndrome be considered for reclassification of an individual into a higher risk category (ie, for risk refinement as described later in this document).

However, because of the overlap between certain ASCVD risk factors and metabolic syndrome criteria (eg, HDL-C and triglycerides), the panel as a whole did not agree that the metabolic syndrome should be labeled a high risk condition at this time. The main value of identifying the presence of the metabolic syndrome is to recognize individuals with a high potential to benefit from lifestyle therapies, particularly weight loss if overweight or obese and increased physical activity. Successful lifestyle intervention will reduce adiposity and insulin resistance, improving multiple physiological disturbances that may contribute to risk, including the metabolic syndrome components as well as indicators of inflammation, oxidation, and thrombogenicity.

Waist circumference thresholds are presented in the list of metabolic syndrome components because waist is generally considered to be a better indicator of abdominal obesity than body mass index, BMI. However, members of the NLA Expert Panel recognized that waist is not always measured in clinical practice, whereas weight and height data for the calculation of BMI are usually available. Thus, although not the preferred indicator, BMI may be used as an alternative to waist circumference when the latter is not available. Using National Health and Nutrition Examination Survey data, the cut points for BMI that produced the same population prevalence rates as the waist criteria were 25.0 kg/m2 for women and 29.0 kg/m2 in men. Lower cut points of 23.0 and 27.0 kg/m2 for women and men, respectively, may be considered for individuals or populations with increased insulin resistance, including those of East Asian, South Asian, or Native American descent.