Cholesterol Conundrum
At first glance, the connection between high cholesterol and increased heart disease risk seems solid. Below the surface, the details look murkier. For starters, many people who have heart attacks don´t have high cholesterol. This is one of the most puzzling aspects of the cholesterol story.
Not All Cholesterol Created Equal
Cholesterol comes in several varieties. One is low-density lipoprotein cholesterol. This type is referred to as LDL cholesterol (LDL-C). LDL-C is so-called "bad" cholesterol. It is believed that LDL-C is most likely to stick to the inside of arteries, causing heart disease.
The other type of cholesterol is high-density lipoprotein cholesterol (HDL-C). HDL-C is so-called "good" cholesterol. HDL-C shuttles cholesterol from the body back to the liver. Less cholesterol in circulation is believed to help keep heart disease at bay.
Heart health experts now focus most on lowering LDL-C. The theory is that lowering bad cholesterol is the most important goal.
Considering Cholesterol
Last year researchers reviewed the cholesterol levels of 136,000 people hospitalized for heart attacks between 2000 and 2006. In about 75 percent of heart attack patients, LDL-C levels were within the recommended range for reducing heart disease risk. Based on cholesterol levels, three-quarters of people who have heart attacks would not be flagged as being at risk for heart disease!
Equally puzzling is another recent study. Researchers found no significant connection between cholesterol levels and plaque in the arteries of 1,653 men and women. In fact, 26% of those in the study who were taking cholesterol-lowering drugs (statins) had no evidence of arterial plaque.
The study authors concluded some people who are taking statins do not need them. Statins have side effects and risks, some of which are very serious. People who do not need them should not take statins. Also troubling: some people who need medication – those at high risk of heart disease – may not get it.
If this leaves you scratching your head, you´re not alone.
Filling in the Missing Pieces
If total and LDL cholesterol levels don´t have much to do with heart disease, why focus on them? It turns out that lowering cholesterol with statin drugs does lower heart disease risk. But is it less cholesterol or something else that accounts for reduced risk of heart disease?
Statins lower cholesterol, but they do many other things too. Statins have potent anti-inflammatory actions. Inflammation increases heart disease risk even in people with lower cholesterol levels, so less inflammation is better.
Statins decrease the "stickiness" of blood cells. This helps prevent the clots that can cause a heart attack. Statins may encourage the body to form "collateral vessels". These new blood vessels can help route blood around a narrow space in another vessel.
Even this isn´t the whole picture. Another blood fat is the triglyceride. Triglycerides make LDL-C denser and stickier. When you have a lot of LDL-C and a lot of triglycerides, LDL-C is more damaging to arteries.
There are other types of cholesterol too. Very-low-density-lipoprotein cholesterol or VLDL-C may play a role in heart disease risk. Within the HDL-C and LDL-C groups are different versions (sub-types) of each type of cholesterol. Some sub-types may increase heart disease risk a lot. Others may not.
The Full Picture
In the end, other factors that cause heart disease may increase LDL-C too. This would make it appear that LDL-C causes heart disease. In reality, those other factors are causing both the heart disease and the high cholesterol. These factors might include lack of physical activity, obesity, smoking, stress, pollution, and a poor diet.
Beyond Statins
It´s important to keep in mind that some people have genetic cholesterol syndromes, called hyperlipidemias. "Hyper" means a lot. "lipid" refers to fat, including cholesterol and triglycerides. "Emia" means in the blood.
For people with genetic hyperlipidemias, statins are a lifesaver. If you have one of these conditions, you simply cannot eat or exercise your way out of increased heart disease risk. Typically, people with hyperlipidemias have cholesterol in the 300-400 range. Triglycerides can be as high as 1000-2000. If this describes you, do not stop taking statins.
Taking Control of Your Heart Health
For the vast majority of people with high cholesterol, a more nuanced assessment makes sense. A new University of Michigan study validates this approach.
Lead study author Dr. Rodney Hayward states, "We´ve been worrying too much about people´s cholesterol level and not enough about their overall risk of heart disease." Statins are helpful for some people, but patients and doctors should consider all of the factors that affect a person´s risk of heart attack and strokes.
This includes age, family history, diabetes, high blood pressure, smoking status, and C-reactive protein (CRP). CRP is a way to measure how much inflammation is occurring in a person´s body. More inflammation means higher risk of heart disease and other chronic diseases.
Cholesterol Down: Ten Simple Steps to Lower Your Cholesterol in Four Weeks--Without Prescription Drugs
Dr. Hayward concludes that knowing your overall heart attack risk is more important than knowing your cholesterol level. If your overall risk is high, you should probably take a statin, regardless of your cholesterol level. On the other hand, if your LDL-C is high, but your total heart disease risk is low, skip the statin. Make a healthy diet and regular exercise a prior
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