Metabolic syndrome

The metabolic syndrome is a combination of metabolic abnormalities including abdominal obesity, dyslipidaemia, elevated blood pressure, and elevated fasting glucose or insulin resistance, respectively. These factors predispose an increased risk for type 2 diabetes mellitus and cardiovascular disease (CVD) (Saklayen, 2018).

The metabolic syndrome is a pathophysiologic state which is associated with increased risk for serious health consequences, no matter what definition the diagnosis is based on (Saklayen, 2018). Definitions for the metabolic syndrome vary because of discord over thresholds and weighing for specific diagnostic criteria (Bentley-Lewis et al., 2007, Saklayen, 2018, Alberti et al., 2009). In 2009, the definition was tried to be harmonised by the International Diabetes Federation (Alberti et al., 2009) but despite these efforts definitions from the WHO 1999 (Alberti & Zimmet, 1998), the National Cholesterol Education Program (NCEP ATP3) 2005 (Grundy et al., 2005), and the International Diabetes Federation (IDF) 2006 are still frequently used in practice. The differences between the definitions are small (Saklayen, 2018).

These definitions are only valid for adult populations. For children and adolescents there are specific diagnostic criteria referring to the paediatric metabolic syndrome (Higgins & Adeli, 2017).

The most common diagnostic criteria for the metabolic syndrome in adults are:

Abdominal obesity, indicated by a large waistline

Elevated fasting blood glucoseconcentrations:

Elevated triglyceride concentrations:

Decreased HDL cholesterolconcentrations:

Increased blood pressure:

Depending on the institution, the weighing of these criteria varies: For their diagnosis of metabolic syndrome, the WHO makes the presence of insulin resistance the highest weighing factor whereas the IDF and Alberti et al. make waist circumference mandatory. In both instances, the predominant factor has to be present in combination with any two or more of the other criteria. In contrast, the NCEP ATP3 defines almost the same thresholds as the IDF yet requires that a combination of three or more of their diagnostic criteria is met.

Other diagnosis criteria for the metabolic syndrome exist but are not as commonly used. These include those of the Association of Clinical Endocrinologist 2003 and the European Group for the Study of Insulin Resistance (Saklayen, 2018, Aguilar-Salinas & Viveros-Ruiz, 2019).

Synonyms: Dysmetabolic syndrome, Hypertriglyceridemic waist, Insulin resistance syndrome, Obesity syndrome, Syndrome X