If you do not subscribe to the Sacramento Bee then you may have missed the article that was placed in one of the bottom corners of the front page last Thursday, May 17th. The article highlighted a new study conducted by researchers at The Broad Institute and Massachusetts General Hospital that challenged the accepted notion that raising a person's levels of HDL-or the good cholesterol-will result in a decreased risk of heart attack.
This comes as quite a shock to medical professionals because for the last thirty years, it has been the accepted opinion that if you could raise a person's HDL levels, their risk of heart attack would go down dramatically and they would essentially be "safe" from an early death. Operating under this assumption, there has been an attempt to develop drugs to raise HDL levels with the hope that they would have as much success as statins-or a drug that lowers LDL-the bad cholesterol-levels in the blood have had.
The study examined 170,000 individuals for genetic markers that made them predisposed to having high HDL levels and found that they were at no less risk of heart attack then individuals who did not possess these markers. While this is ground breaking research, the issue comes when sources such as the Sacramento Bee use these findings to make it sound like HDL is no longer important.
Last week, the Clinical Health Appraisals team had to confront this issue when patients who were undergoing blood lipid analysis would remark, "why are you doing this test for HDL levels? I heard it doesn't really matter anymore." The truth is, HDL does matter, but the capacity to which we had previously assigned it has changed. Cholesterol is carried by molecules called lipoproteins in the blood. High levels of Low Density Lipoproteins or LDL, has been proven to increase a person's risk for heart disease in countless large scale studies.
When life saving statins were developed, it seemed that the logical course of action would be to develop a drug that would raise HDL levels and all the world's cholesterol issues would be solved. Until the development of a truly effective drug occurred, physicians and medical professionals operated under the “play it safe” policy and advised nearly everyone with low HDL levels that it was essential to raise them. Now it seems that raising HDL is not the be-all end all when it comes to preventing Heart Disease. What is more likely is that high HDL levels and decreased risk of heart attack are correlational not causational. Meaning, they happen to occur that the same time but one does not necessarily lead to another.
Benjamin Voight, PhD one of the authors of the original paper (highlighted below) summed it up:
"There are many biomarkers measurable in the blood that track with disease but only a very small number are actually causal and directly participate. The reason you want to distinguish between causal and non-causal biomarkers is because of the implications for therapy.” Basically, it is extremely important to understand the genetic background and interactions of the bio-markers you are trying to develop a drug for, before moving to mass production and prescription of said drug.
Senior author Sekar Kathiresan, director of preventive cardiology at MGH, associate professor of medicine at Harvard Medical School, and an associate member of the Broad Institute put is like this:
“We know that HDL is a great biomarker — it’s quite useful in identifying individuals at higher risk of having a heart attack in the future. But we have shown that you cannot assume that raising HDL by any mechanism will help patients. Perhaps other mechanisms exist that can lower risk, but we will need to keep searching for them.”
What this means for the patient and the doctor is, if the patient is diagnosed as having a low HDL level, should you immediately worry about jumping on newest medication that claims to raise HDL? No, in fact what we should all do is look at the other factors that may be causing a lowered HDL level. Is the patient eating properly, exercising regularly, drinking to excess, getting enough sleep? Do they have elevated levels of LDL and Total Cholesterol?
If the answers imply that the patient is not living a healthy lifestyle, then the prescription of diet and exercise that usually accompanies a low HDL finding is entirely appropriate. Though it seems now that raising HDL alone might not be the key to preventing heart disease, the lifestyle changes that accompany an HDL raising regime will help prevent disease in the future by lowering LDL and Total Cholesterol, increasing cardiovascular fitness, bone density, quality of sleep, and overall well-being.
This, along with a million other positive effects is reason enough to say that YES! HDL is STILL IMPORTANT, but not just by itself. You have to take other risk factors into account and ask yourself, am I living the most out of this life I have? One day, they will discover what HDL's role in maintaining a healthy cardiovascular system is, but until then, we need to look at the big picture and think, is what I am doing today going to help or hurt this one body I have when I am 40? 50? 60? 70? If the answer is negative, then it's not so much the numbers we get in a blood test that we need to be concerned with, but the life style that is giving rise to those numbers.
Have a healthful week!
-CHA
Original Article on the Massachusetts General Hospital website
Original Study published in The Lancet
Sacramento Bee Article-May 17th
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