Your LDL cholesterol reading may be 40 points off

As you are probably aware, cholesterol is neither good nor bad. There is the "good" or high density lipoprotein (HDL) cholesterol, and the "bad" or low density lipoprotein (LDL) cholesterol. Given that one is considered good and one is considered bad, you wonder why their absolute values are added in the first place to obtain the total cholesterol (TC) as it is done in the US. Think about it! For a little math problem, let's suppose Johny has 90 red marbles and 10 black marbles, while Susie has 10 red marbles and 90 black ones. However we don't know that. We're only told black marbles are good and red marbles are bad and each person has 100 marbles. How would we know who has the better marbles? And if another person came along with 120 marbles, is that "worse" than 100? Only if the additional marbles are red. Do we assume that more marbles are necessarily bad marbles? Obviously, no mathematicians were consulted when this crazy system was developed. It has its basis in history.

In the early days, they didn't know about LDL and HDL. They only knew this "cholesterol" number. This was the Total Cholesterol that they measured. Then they began to study in more detail and they found out that the HD component actually was good. HDL is pretty easy to measure. LDL, apparently, is not. So when you subtract off the HDL, whatever is left must be LDL, right? Well pretty much. When you have a good thing and a bad thing (e.g. signal and noise), the ratio between them is more important. At a glacial pace, the USA medical establishment is finally getting their heads around this. Most doctors now are teling you that your HDL/LDL ratio should be above 1:4 or 0.25 (i.e. 25%)

So the LDL is just the TC minus the HDL, right? No not quite. There's a third factor called triglycerides, and for whatever reason, they don't exactly add up, but based on experiments they definitely affect it. Most of the time, the LDL reading you get when you have a cholesterol test is calculated using the formula LDL = TC - HDL - (TG/5). The reason for this? Actually measuring the LDL is a slightly more expensive test. The cheap test that is normally used for cholesterol screening measures the total cholesterol (TC), the HDL and some other plasma factors known as triglycerides.

The formula was made up by a doctor called Friedewald, and I mean it when I say "made up." It was based on empirical data, and the formula was developed to fit measured results. It is a heuristic (something that just sort of seems to work). It fits average data very well. Note that I am not saying normal. Normal is not the same thing as average. There are triglyceride readings within the realm of normal that are very unusual, and for these people, the formula is a very poor predictor of their actual measured LDL.

There was a medical report online that I used while researching this hub. I originally linked to it  but it has since gone away.  (Sorry, these things happen)  The report first refers to a previous report that found that if the TG is very high it will artificially lower the calculated LDL. Then it gives a case of a patient who had a very low TG and using this formula the calculated LDL was artificially high. They proved it by actually measuring the LDL and comparing it to the prediction. It was way way off for him -- so badly off that it completely changed how they viewed his cholesterol. When they measured it it was just below borderline. When they guessed at it, it was in the "needs drugs" category. It doesn't take a mathematical genius to see why the Friedewald formula fails for exceptionally high or low TG levels! If you subtract a very big number (even one divided by 5) you will have a smaller number left. Conversely if you subtract a very small number you will have a bigger number left. Freidewald was certainly no mathematician.

Here is where it starts to get scary. Doctors can mess with numbers like these til the cows come home as long as it's just interesting information about their patients. But when they use estimated LDL as a basis for prescribing statin drugs, that's where I draw the line.

The screening test is being used as a treatment determinant. I think that before anyone consents to take statin drugs (believe me, they're scary) they should insist that their LDL be measured, because as you see from the reference article, the calculated results can be way off. Doctors are giving out statin drugs to children these days based on the Friedewald heuristic. Doctors are using drugs as a first resort, instead of appropriately as a last resort. They assume that "diet and exercise" aren't going to really work. Drugs are the only things that really work so might as well just go straight to the drugs. And big pharma is standing on the sidelines, cheerleading and clapping them on the back. You Go Doc!!! Who doesn't like to be told how great they are. And meanwhile those cheerleaders are raking in the bucks.

A doctor might say to a patient with a dismissive tone of voice, "well you could try the diet ad exercise (eye rolling says yeah and we know how well THAT works) but come back after it fails and I'll give you something that will knock that cholesterol on its ass. Ignoring that the doctor didn't really give any specific recommendations for diet and exercise, we also note that people are very responsive to unspoken messages. They are being set up to fail at taking responsibility for their own health and just take the easy way and let drugs do it for them. For both doctor and patient, drugs are easy. Just remember to pop this pill every day.

Another scientific beef I have: It's pretty clear that statins drive the cholesterol numbers down, but there has never been a solid proof that cholesterol CAUSES atherosclerosis, only correlations between the two. It is possible that a third factor causes both! Here's a wikipedia example. Is it not conceivable that in the same way HRT was not actually causing lower heart disease risk, so cholesterol isn't causing atherosclerosis. If you lower the cholesterol, but the cholesterol was a result rather than a cause, you haven't affected the atherosclerosis at all because you have not removed whatever third factor is causing it.