Does high cholesterol alone mean you’ll develop heart disease? Is there an ideal cholesterol reading? A top cardiologist answers some common questions about cholesterol levels and shares details about some exciting new treatments on the horizon. Plus, find out how well you understand cholesterol with our quiz...
Is cholesterol as bad as many of us think?
It’s linked to heart disease: People with high total cholesterol– one of every six adults in the U.S. –run twice the risk of heart disease as those with optimal levels, according to the U.S. Centers for Disease Control and Prevention. But is cholesterol solely to blame?
And does a high cholesterol level automatically equal heart disease?
We spoke to cardiologist Prediman K. Shah, M.D., director of the cardiology division at Cedars-Sinai Heart Institute and Medical Center in Los Angeles, to get answers– as well as learn about promising research that may give high cholesterol levels the boot for good.
Some people claim cholesterol isn’t linked to heart disease. Can you shed some light on this?
There’s absolutely no question that cholesterol is linked to heart disease. Research clearly shows that cholesterol leads to formation of plaque, the substance the blocks the arteries. Without cholesterol, you can’t get arterial blockage. But cholesterol alone is not the cause of heart disease.
Something else besides a high cholesterol level creates heart disease?
Yes. Some people have high cholesterol and never have plaque. Some people with average cholesterol will have extreme plaque.
Besides cholesterol, inflammation also produces the plaque that builds up in arteries and contributes to heart disease. Without inflammation, cholesterol doesn’t convert into plaque.
People differ in terms of susceptibility to inflammation, which affects their likelihood of developing plaque and heart disease. So cholesterol causes arterial blockage, but not by itself.
What do we know about the inflammation process then?
A certain type of cholesterol – LDL, the so-called bad cholesterol– is implicated in inflammation. When LDL cholesterol gets trapped in an artery, it oxidizes – that is, converts to an irritant. This irritant causes inflammation, which contributes to thickening of the arterial wall and more cholesterol deposits and plaque formation.
Compelling research shows that if we eliminate certain inflammation genes in a mouse with high cholesterol levels between 1,000 and 2,000 [mg/dL], very little plaque develops in the arterial walls. So inflammation is necessary to transform high cholesterol into plaque. We can’t do those same studies in humans, but we believe it’s a similar process.
Are the same genes that prompt other types of inflammation – arthritic inflammation, for example – also responsible for inflammation in arteries?
Some genes involved in inflammation in the heart are common to other diseases, and some are very specific to the arterial wall.
People generally think bad LDL cholesterol should be below 100 and the good HDL should be 60 and above. What is an ideal cholesterol reading?
It’s actually a little complicated. Those are good guidelines, but what is ideal for you may be bad for me. No two people with the same cholesterol levels will have the same degree of plaque.
My body might respond with an inflammatory response to lower cholesterol levels . If you have a less responsive inflammatory system, you might escape heart disease, despite having higher cholesterol. So there’s a lot of individual variability.
How can you find out how responsive (or not) your inflammatory system is? Is there a test?
Unfortunately, there is not a test to find out if you are a plaque-former or not. But a CT scan of the heart and an ultrasound of carotid arteries are very useful tools.
If you’re over 60 years old with elevated cholesterol, yet a CT scan of the heart and an ultrasound of the carotid arteries show you’re free of plaque, we know something is protecting you.
If your grandparents or parents didn’t suffer from heart disease, are you free and clear?
No, not at all. Children don’t automatically inherit the blunting effect.
If someone is 60-plus and you find through imaging they don’t have high cholesterol levels, what then?
I tell them there’s no need to take medication, but they should still follow a heart-healthy lifestyle.
Should everyone have a CT scan of the heart and ultrasound of the carotid arteries to determine if they should take medication?
No, that’s not necessary. You have to consider the risk profile. If a patient is ultra-low risk, I wouldn’t do imaging or give medication. And if the patient is ultra-high [risk], I’d just prescribe medication regardless. It’s really the in-between people with whom we use imaging.
I helped develop the SHAPE [Screening for Heart Attack Prevention and Eradication] guidelines that clarify this. These were guidelines recommended to the public in 2006. At that time, they were not widely accepted. But now, the American Heart Association and others are also recommending imaging for intermediate-risk patients.
Why wouldn’t everyone want these tests to check for high cholesterol levels, though? Are they risky or expensive?
The test is not expensive anymore. At Cedars-Sinai, it’s less than $200.There is some degree of radiation involved, though.
You don’t want to do anything with radiation willy-nilly. You want to use it only in people who are most likely to benefit. That said, the level of radiation is actually coming down, because technology is always getting better.
Can you explain the risk categories for cardiac disease?
Ultra low is someone with no family history of cardiac disease, LDL below 100, normal HDL, no diabetes, no high blood pressure, doesn’t smoke, is physically active and isn’t obese. If, under these circumstances, you have cholesterol clog an artery, it’s like lightning striking – extremely rare.
High risk would be somebody who is a smoker, diabetic, has high cholesterol levels, is obese and has high blood pressure. The vast majority of these people will automatically be prescribed medication [to lower their cholesterol].
But in between is a very large group. That’s where we can use imaging to decide whom to treat aggressively with medication and who doesn’t need it.
When you’re considering cholesterol-lowering medication, cost is not the only factor. You’re also considering a lifelong treatment of drugs that do carry some side effects.
What kind of side effects?
The most common side effects of statins include muscle aches and muscle weakness. One of 10 people who take statins will have muscle soreness or stiffness. This side effect usually goes away if you change medication or dose. But there are some reports of neuro-muscular side effects persisting years after drug cessation.
People always worry about liver damage, but fewer than one of 1,000 will experience any negative side effects that have to do with the liver.
Still, statins are the most effective treatment to lower LDL cholesterol. Research backs up the claim that lowering cholesterol reduces cardiac risk, but statins haven’t eliminated heart attacks and strokes. And not everyone can take them.
People on immuno-suppressants and antiretroviral medications, for example, have to be careful because there could be a drug-to-drug interaction. People with liver disease also can’t take them.
Recently, the National Institutes of Health halted a study that was testing statins to lower LDL, along with niacin to raise HDL. Apparently the treatment for high cholesterol levels wasn’t working and even perhaps may slightly increase stroke risk. Are you concerned about this common practice of doctors combining niacin with a statin?
We shouldn’t jump on the bandwagon of demonizing this treatment quite yet. I’ve been a big prescriber of niacin [with a statin] because all prior data was supportive. So I was a bit puzzled and surprised when the study was stopped. I would like to see the data. It will probably take a few months before we understand what happened.
You have some exciting research going on right now. Can you tell us about it?
We’re working on a number of issues related to atherosclerosis and cholesterol. One involves the concept of vaccinations against LDL cholesterol buildup. We’ve developed this vaccine over the last 15 years in collaboration with Dr. Jan Nilsson, a Swedish scientist.
LDL contains a protein called ApoB-100. There’s evidence that ApoB-100 contains the antigen to LDL cholesterol. That is, it triggers an immune response that can reduce [bad] cholesterol and plaque in arteries.
We’ve been taking antigens from ApoB-100, making synthetic copies in the lab and using them in vaccinations to reduce inflammation and plaque in animal models. We’re hoping to complete these studies by the end of year.
How important might a cholesterol vaccine be?
It could be a game-changer. Imagine if you could vaccinate children against heart disease. It’s a possibility.
And your other cholesterol research?
The other idea is based on a mutant gene that occurs in about 40 families in Limone Sul Garda in Italy. The gene has a protein– ApoA-1 Milano– that was discovered to have a protective effect on the heart. When injected, it stops plaque formation in rabbits and mice. So it can halt and reverse plaque buildup.
A 2003 study showed the reversal of plaque in coronary arteries within five weeks of an ApoA-1 Milano protein injection. It’s a very difficult protein to produce, though. We’ve been trying three different ways, and at least one may go to human trials in the next couple of years.
Are you optimistic that vaccinations to fight high cholesterol levels may someday be widely used?
I’m cautiously optimistic.
In the meantime, what’s your advice to people regarding cholesterol?
Choose your parents wisely! There’s a genetic propensity to high cholesterol. Other than that, eat healthy and exercise. Don’t smoke. See your doctor to get your cholesterol checked. And, for now, take your statin medication if you need it.
For more information and expert advice, visit our Cholesterol Health Center.
How Well Do You Understand Cholesterol?
Cholesterol is much maligned, yet many people don’t understand this essential substance and how it works in our bodies. Do you know your HDL from your LDL? How about which lifestyle choices influence cholesterol levels?
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