New Guidelines on Metabolic Syndrome

Examining the historical background of metabolic syndrome provides critical insight into its complexity as well as the evolution of its terminology and diagnostic frameworks. The earliest documented observations linking excessive food consumption, obesity, and cardiovascular disturbances date back to ancient Egypt, where accounts described sudden cardiac arrest in individuals with elevated body weight. Systematic descriptions of cases resembling the modern understanding of metabolic syndrome likely emerged in the 17th and 18th centuries, but it was not until the 20th century that scientific research began to systematically explore the relationships between lifestyle factors and the development of metabolic disorders—including insulin resistance, dyslipidemia, and hypertension. Earlier attempts to classify this cluster of conditions employed terms such as "triad syndrome" or "syndrome of affluence," reflecting contemporaneous perceptions of socioeconomic causes. The formal designation "metabolic syndrome" was proposed in 1981 by German researchers, with its initial definition encompassing the co-occurrence of obesity, type 2 diabetes, hyperlipidemia (elevated total cholesterol and triglyceride levels), hypertension, and gout—conditions that significantly increase the risk of coronary artery disease and renal calculi. Over subsequent decades, various medical organizations, including the World Health Organization (WHO), the International Diabetes Federation (IDF), and the American Heart Association (AHA), developed distinct diagnostic criteria that varied in both selected parameters and threshold values. The most recent consensus, published in 2009 by the IDF in collaboration with the AHA and the National Heart, Lung, and Blood Institute (NHLBI), establishes that metabolic syndrome may be diagnosed when at least three of five criteria are met: (1) abdominal obesity (waist circumference ≥ 94 cm in men and ≥ 80 cm in women for European populations), (2) hypertriglyceridemia (≥ 150 mg/dL or triglyceride-lowering therapy), (3) low HDL cholesterol (< 40 mg/dL in men and < 50 mg/dL in women or HDL-raising treatment), (4) elevated blood pressure (≥ 130/85 mmHg or antihypertensive therapy), and (5) elevated fasting glucose (≥ 100 mg/dL or glucose-lowering treatment).