11. August 2006 William Davis (0)
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.
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Low HDL makes Dr. Friedewald a liar

Low HDL makes Dr. Friedewald a liar

17. March 2007 William Davis (5)
There's a $22 billion industry based on treating LDL cholesterol, a fictitious number.

LDL cholesterol is calculated from the following equation:

LDL cholesterol = Total cholesterol - HDL cholesterol - triglycerides/5

So when your doctor tells you that your LDL cholesterol is X, 99% of the time it has been calculated. This is based on the empiric calculation developed by Dr. Friedwald in the 1960s. Back then, it was a reasonable solution, just like bacon and eggs was a reasonable breakfast and a '62 Rambler was a reasonable automobile.

One of the problems with Dr. Friedewald's calculation is that the lower HDL cholesterol, the less accurate LDL cholesterol becomes. If it were just a few points, so what? But what if it were commonly 50 to 100 mg/dl inaccurate? In other words, your doctor tells you that your LDL is 120 mg/dl, but the real number is somewhere between 170 and 220 mg/dl. Does this happen?

You bet it does. In my experience, it is an everyday event. In fact, I'm actually surprised when the Friedewald calculated LDL closely approximates true LDL--it's the exception.

Dr. Friedewald would likely have explained that, when applied to a large population of, say, 10,000 people, calculated LDL is a good representation of true LDL. However, just like saying that the average weight for an American woman is 176 lbs (that's true, by the way), does that mean if you weigh 125 lbs that you are "off" by 41 lbs? No, but it shows how you cannot apply the statistical observations made in large populations to a single individual.

The lower HDL goes, the more inaccurate LDL becomes. This would be acceptable if most HDLs still permitted reasonable estimation of LDL--but it does not. LDL begins to become significantly inaccurate with HDL below 60 mg/dl.

How to get around this antiquated formula? In order of most accurate to least accurate:

--LDL particle number (NMR)--the most accurate by far.

--Apoprotein B--available in most laboratories.

--"Direct" LDL

--Non-HDL--i.e., the calculation of total cholesterol minus HDL. But it's still a calculated with built-in flaws.

--LDL by Friedewald calculation.

My personal view: you need to get an NMR if you want to know what your LDL truly is. A month of Lipitor costs around $80-120. A basic NMR costs less than $90. It's a relative bargain.
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Comments (5) -

  • Mike

    3/18/2007 1:52:00 AM |

    What is shocking is that enormous prescriptions for statins are written based on the calculated LDL.

  • Dr. Davis

    3/18/2007 1:16:00 PM |

    Yes, $22 billion last year, in fact. All prescribed for a number that is a crude estimate, sometimes a complete fiction. Imagine your state trooper ticketed you because his radar device said you were doing 60 mph when you were really doing 35 mph.

  • Anonymous

    2/6/2008 1:37:00 AM |

    Why NMR over the other tests Berkeley Heart Lab or VAP?

  • Anonymous

    7/2/2008 7:02:00 PM |

    I don't understand.  If in this example, the doctor (wrongly) thinks the LDL number is 120mg/dl, how does that cause the prescription of Lipitor? Unless I'm reading it backwards, and the doctor is actually telling the patient their LDL is 170mg-220mg, but unwittingly, it's actually 120mg/dl.

    And, if a low HDL causes the LDL number to be inaccurate, does that also cause the total cholesterol number to be inaccurate too?

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