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Normal cholesterol panel . . . no heart disease?

Posted Jun 15 2011 8:07am

I often hear this comment: “I have a normal cholesterol panel. So I have low risk for heart disease, right?”

While there’s a germ of truth in the statement, there are many exceptions. Having “normal” cholesterol values is far from a guarantee that you won’t drop over at your daughter’s wedding or find yourself lying on a gurney at your nearest profit-center-for-health, aka hospital, heading for the cath lab.

Statistically, large populations do indeed show fewer heart attacks at the lower end of the curve for low total and  LDL cholesterol and the higher end of HDL. But that’s on a population basis. When applied to a specific individual, population observations can fall apart. Heart attack can occur at the low risk end of the curve; no heart attack can occur at the high risk end of the curve.

First of all, to me a “normal” lipid panel is not adhering to the lax notion of “normal” specified in the lab’s “reference range” drawn from population observations. Most labs, for instance, specify that an HDL cholesterol of 40 mg/dl or more and triglycerides of 150 mg/dl or less are in the normal ranges. However, heart disease can readily occur with normal values of, say, an HDL of 48 mg/dl and triglycerides of 125 mg/dl, both of which allow substantial small oxidation-prone LDL particles to develop. So “normal” may not be ideal or desirable. Look at any study comparing people with heart disease vs. those without, for instance: Typical HDLs in people with heart attacks are around 46 mg/dl, while HDLs in people without heart attacks typically average 48 mg/dl–there is nearly perfect overlap in the distribution curves.

There are also causes for heart disease that are not revealed by the lipid values. Lipoprotein(a), or Lp(a), is among the most important exceptions: You can have a heart attack, stroke, three stents or bypass surgery at age 40 even with spectacular lipid values if you have this genetically-determined condition. And it’s not rare, since 11% of the population express it. How about people with the apo E2 genetic variation? These people tend to have normal fasting cholesterol values (if they have only one copy of E2, not two) but have extravagant abnormalities after they eat that contribute to risk. You won’t know this from a standard cholesterol panel.

Vitamin D deficiency can be suggested by low HDL and omega-3 fatty acid deficiency suggested by higher triglycerides, but deficiencies of both can exist in severe degrees even with reasonably favorable ranges for both lipid values. Despite the recent inane comments by the Institute of Medicine committee , from what I’ve witnessed from replacing vitamin D to achieve serum 25-hydroxy vitamin D levels of 60-70 ng/ml, vitamin D deficiency is among the most powerful and correctable causes of heart disease I’ve ever seen. And, while greater quantities of omega-3 fatty acids from fish oil are associated with lower triglycerides, they are even better at reducing postprandial phenomena, i.e., the after-eating flood of lipoproteins like VLDL and chylomicron remnants, that underlie formation of much atherosclerotic plaque–but not revealed by fasting lipids.

I view standard cholesterol panels as the 1963 version of heart disease prediction. We’ve come a long way since then and we now have far better tools for prediction of heart attack. Yet the majority of physicians and the public still follow the outdated notion that a cholesterol panel is sufficient to predict your heart’s future. Nostalgic, quaint perhaps, but as outdated as transistor radios and prime time acts on the Ed Sullivan show.

 

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