For decades, doctors have believed that high cholesterol is a major cause of the artery blockages that lead to heart disease and stroke. Moreover, worries about high cholesterol levels have worked their way into popular consciousness.
A survey carried out in the US in 2002 estimates that over 3mn Americans were using some kind of alternative medical treatment to lower their cholesterol.
Drugs that claim to achieve this have been one of the largest revenue streams for pharmaceutical firms over the past two decades.
It’s hard to avoid the barrage of conflicting information about cholesterol as it pertains to life in Japan.
If and when we find out our cholesterol is high during a company physical, most of us have three questions: “Is it really that high?”, “Why is it high?” and—as the character Pete in the comedy This is 40 might ask—“Does this mean my heart is going to explode?”
Reports can be misleading
To answer the first question, I should note that there is no clear definition of so-called high results.
In most blood tests, the top and bottom 2.5% of the results for any population are classified as high and low, respectively; the remaining 95% of the results are deemed normal.
Cholesterol results, however, are treated completely differently. When there is some medical evidence that the patient will benefit from lowering either their overall or their LDL (bad) cholesterol levels, a result is reported as high. In many countries this leads to more than half the population being classified as having high cholesterol.
Therefore, if your cholesterol is just over the reference range quoted on a set of blood test results, it is likely to be more or less the same as that of most of the people around you.
Not just a lifestyle disease
As to why cholesterol levels are high, the popular perception has become that this is entirely a lifestyle disease, that it is the direct result of inactivity, being overweight, and/or eating poorly. While there is some truth to this, cholesterol levels also have a strong genetic component.
Cholesterol is an essential building block used to make, for example, many of the sex hormones in our body, and thus we can’t live without it. Because of this, our bodies continuously produce cholesterol in the liver.
While much of the cholesterol in our systems does come from food, reducing or even eliminating our cholesterol intake will usually cause our bodies to compensate by making even more cholesterol.
Each person has a genetically predetermined level of cholesterol production; some people have livers that are programmed to make quite a lot. As a result, they may have high cholesterol despite leading very healthy lives.
While lifestyle changes can reduce cholesterol levels, the extent to which they actually fall can be quite disappointing.
My experience has shown that most people have a hard time reducing their cholesterol by more than 15–20% without making very extreme changes to their diet and exercise patterns.
Risk is relative
Finally, to answer the third question, how dangerous is high cholesterol?
For some people, it’s hardly dangerous at all, while for others it can be life-threatening. Cholesterol is just one of several factors that work together to determine a person’s risk of heart disease.
A young, healthy female who does not smoke would have a very low risk of heart disease even with high cholesterol. At the other end of the spectrum, an overweight man in his late 50s who is diabetic, smokes, and has high blood pressure and cholesterol levels would be at risk of developing heart disease. Reducing his cholesterol would be a priority.
With this in mind, let’s give a risk score to Pete from This is 40.
He’s a male non-smoker, is not overweight and is, of course, 40 years old. His father, who appears in the film, does not seem to have suffered from heart disease, so let’s assume there is no family history of heart problems. Let’s also say Pete’s blood pressure is fine and he isn’t diabetic.
All this information can be entered into in a risk stratification tool—available online or through a smartphone application—to determine Pete’s risk of having a heart attack before his 50th birthday.
We know Pete’s total cholesterol level is 300. I’ve assumed his LDL cholesterol is high, perhaps a little under 200, and that he has an HDL (good) cholesterol reading of about 45, which is average.
Given all these factors, his risk of a heart attack in the next decade comes out at 5%, which is moderate. At this rate most doctors would not automatically recommend he take cholesterol-lowering drugs.
However, if he were a smoker (cardiac risk increases to 16% over 10 years), medication would be an option.
The take-home message for all of us is to know not only how high our cholesterol is, but how much risk that level implies.
I recommend that people concerned about their cholesterol discuss the issue with their doctor. They might be able to avoid being put on medication for life, simply because a single blood test came back high.