The epidemic of obesity in the Western world has increased not only the prevalence of type 2 diabetes but also the prevalence of a constellation of findings usually called the metabolic syndrome.
People with the metabolic syndrome are at greatly increased risk for developing type 2 diabetes, coronary heart disease, and nonalcoholic fatty liver. Although several different definitions have been suggested for the metabolic syndrome, the one used by the National Cholesterol Education Panel (NCEP) is the most common. They proposed that individuals have the metabolic syndrome if they are positive for three or more of the following factors:
- Abdominal obesity -- waist circumference greater than 40 inches in men and greater than 35 inches in women
- Blood pressure greater than 135/85 mm Hg
- Fasting blood sugar greater than 110 mg/dL
- Triglycerides greater than 150 mg/dL
- High density lipoprotein cholesterol less than 40 mg/dL in men or less than 50 mg/dL in women
The most common cause of the metabolic syndrome is the body's resistance to the action of insulin, though genetic factors and increasing age also can contribute. Abdominal obesity, rather than weight itself, is used to define the metabolic syndrome because fat within the abdomen is especially prone to produce insulin resistance.
The prevalence of the metabolic syndrome increases with age. Fewer than one in six people under age 30 in the United States, but nearly half of the men and women over the age of 50, have the metabolic syndrome and are thereby at higher risk for type 2 diabetes and coronary heart disease.