The recognition of the metabolic syndrome as a distinct collection of factors that raise heart disease risk has been a great step forward in helping us understand many of the causes behind heart disease.
Curiously, there's not complete agreement on precisely how to define metabolic syndrome. The American Heart Association and the National Heart, Lung, and Blood Institute issued a concensus statement in 2005 that "defined" metabolic syndrome as anyone having any 3 of the 5 following signs:
Waist size 40 inches or greater in men; 35 inches or greater in women
Triglycerides 150 mg/dL or greater (or treatment for high triglycerides)
HDL-C <40 mg/dL in men; <50 mg/dL in women (or treatment for reduced HDL-C)
Blood Pressure >130 mmHg systolic; or >85 mmHg diastolic (or drug treatment for hypertension)
Glucose (fasting) >100 mg/dL (or drug treatment for elevated glucose)
Using this definition, it has become clear that meeting these criteria triple your risk of heart attack.
But can you have the risk of metabolic syndrome even without meeting the criteria? What if your waste size (male) is, 36 inches, not the 40 inches required to meet that criterion; and your triglycerides are 160, but you meet none of the other requirements?
In our experience, you certainly can carry the same risk. Why? The crude criteria developed for the primary practitioner tries to employ pedestrian, everyday measures.
We see people every day who do not meet the criteria of the metabolic syndrome yet have hidden factors that still confer the same risk. This includes small LDL; a lack of healthy large HDL despite a normal total HDL; postprandial IDL; exercise-induced high blood pressure; and inflammation. These are all associated with the metabolic syndrome, too, but they are not part of the standard definition.
I take issue in particular with the waist requirement. This one measure has, in fact, gotten lots of press lately. Some people have even claimed that waist size is the only requirement necessary to diagnose metabolic syndrome.
Our experience is that features of the metabolic syndrome can occur at any waist size, though it increases in likelihood and severity the larger the waist size. I have seen hundreds of instances in which waist size was 32-38 inches in a male, far less than 35 inches in a female, yet small LDL is wildly out of control, IDL is sky high, and C-reactive protein is markedly increased. These people obtain substantial risk from these patterns, though they don't meet the standard definition.
To me, having to meet the waist requirement for recogition of metabolic syndrome is like finally accepting that you have breast cancer when you feel the two-inch mass in your breast--it's too late.
Recognize that the standard definition when you seen it is a crude tool meant for broad consumption. You and I can do far better.