I went to have my own cholesterol checked a couple of months ago as part of an annual health check, and had an appointment afterwards to follow up on the results. I knew it was elevated before I even entered the room; my GP had already given me that sort of slightly tilted head look they often give before dispensing some form of bad news. I’m guilty of it too.
It’s usually considered wise that GPs don’t act as their own GP, and so they very kindly talked me through the options, although I was already rather familiar with them. Broadly, when faced with significantly raised cholesterol, there are three: do nothing (the least advisable); make a concerted effort to improve things through diet, exercise and other lifestyle changes (often a very reasonable first step); or start a statin – a common, effective, and for many people, necessary treatment.
I elected for option two – in truth there was plenty of scope for me to make some welcome changes. I’ve got enough insight, having seen enough patients with high cholesterol go on to develop complications, to not refuse intervention or sweep the problem under the carpet. But at the same time, I had just enough leeway (and pride) to resist the immediate offer of a statin.
Cholesterol is a rather misunderstood entity. Often people think of it as something inherently bad; that the less of it floating around in our bloodstream, the better. And then there’s the test itself – open your results, and you’re confronted by an often-bamboozling list of different values: HDL, LDL, triglycerides and ratios. Which one are you supposed to worry about? What counts as “good” or “bad” cholesterol? What are we really supposed to think? Or do?
Here are some of the things we get wrong about cholesterol, and some of the myths I try to dispel with my own patients.
Cholesterol is fundamental to body function
While it’s commonly besmirched, the gospel truth is that we simply cannot live without cholesterol. It forms a core component of the membranes of our cells, but is also a building block of Vitamin D, bile salts – which assist the digestion of fats – and a variety of important hormones, including cortisol, oestrogen and testosterone. It also supports the normal function of the nervous and immune systems – helping nerve signals travel efficiently, and tissues grow and repair.
Some patients are found to have unusually low cholesterol levels, sometimes from taking cholesterol-lowering medications, or because of other conditions – like an overactive thyroid, coeliac or liver disease, or metabolic disorders. Interestingly, it appears that having very low cholesterol levels doesn’t appear to cause many problems – which suggests that modest levels of cholesterol are all that we need to function.
The problems we worry about clinically are far more commonly caused by cholesterol in excess. The main complications are cardiovascular diseases (CVD), since cholesterol typically causes arteries to become stiffer, narrowed and more prone to blockage. These conditions are namely coronary artery disease (like angina), stroke or peripheral arterial disease, affecting the limbs. It can also affect the blood flow to other organs too, including the gut and eyes.
Think lipids, not cholesterol
When we measure cholesterol with a blood test, what we actually request is a lipid profile – which measures the levels of several different lipids (or fats) in the bloodstream.
The two main headline numbers to note are high-density and low-density lipoprotein (HDL and LDL, respectively). These correspond to packages of protein and fat that carry cholesterol around the body. They can be thought of as flip sides of the same coin: higher LDL is associated with an increased risk of CVD, whereas higher HDL is associated with a lower risk.
That’s why LDL is often referred to as “bad” cholesterol and HDL as the “good”. In practice, it’s not as simple as that, but it makes for an understandable starting point – generally we want HDL higher, LDL lower – which is easier to remember. Sometimes these values are expressed as a ratio – namely how much of your total cholesterol is HDL. The lower the ratio, the lower the risk.
Another measurement is triglycerides, which are a different form of fatty substance and when raised are also a cardiovascular risk factor. However, their cause – and sometimes their treatment – is different from those of raised LDL cholesterol.
These days the test can be performed without fasting, which makes life easier. What you eat can temporarily affect some readings, particularly triglycerides. But an indulgent period over Christmas or New Year for instance isn’t going to explain away persistently high cholesterol – which usually reflects long-term influences, like diet, weight and the effect of genetics.
And sometimes, raised cholesterol can leave visible clues. Yellow fatty deposits called xanthelasma can gather around the eyelids, while a white or grey ring around the edge of the cornea – known as corneal arcus – can sometimes herald a high cholesterol. Neither is definitive proof, but note them if you spot them. It’s also a good idea to request a lipid test from your doctor.
You might have a healthy lifestyle, but you should still get your cholesterol checked
Genetics can have a powerful influence on cholesterol levels – some patients inherit a tendency towards very high levels of LDL from their parents. This is called familial hypercholesterolaemia and can sometimes cause high cholesterol to be diagnosed in the most unlikely of individuals.
I’ve seen patients who eat exceptionally and consistently healthily, who exercise every day, and have never touched a cigarette in their life – yet have strikingly high cholesterol levels. In these individuals, there is often no scope to manage this with lifestyle alone – they’re already maxed out on all the good stuff. The advisable next step is a statin to bring high cholesterol levels down.
In establishing who needs treatment for high cholesterol, we need to do a bit of maths. Or rather, we let the computer do it for us. In the UK, we commonly use something called a QRISK score. This combines cholesterol values with a range of other factors – including age, sex, weight, blood pressure, smoking history and family history of heart disease – to estimate your risk of developing CVD over the next 10 years.
If your QRISK score is greater than 10 per cent – essentially meaning that you have at least a one-in-10 chance of developing CVD within the next decade, it’s recommended that you should consider taking a statin as prevention.
Statins aren’t something to be scared of
Statins also get bad press – sometimes even more than cholesterol itself – mostly for their potential to cause adverse side effects. But they remain the most readily available, and effective means of lowering LDL cholesterol and reducing the risk of CVD.
Some people will indeed develop side effects while taking them. These include muscle aches and weakness, gastrointestinal upset (such as nausea or diarrhoea), and tiredness. Luckily, more serious complications, like muscle damage, are rare. In some patients, they can also affect the liver – so it’s advisable to get a blood test to check liver enzymes soon afterwards – and you’ll need follow-up blood tests to make sure either the changes you’re making to your lifestyle, or the statin, is working effectively.
Oddly, some patients can also complain of disturbed sleep – from vivid dreams or nightmares – while taking them. Sometimes switching to a different statin can help here.
Give statins a fair go, but do voice any side effects you note along the way. Your doctor really does want to know, since there are often ways to make treatment more tolerable – rather than abandoning them altogether.
My own blood result was a very useful reminder that cholesterol can be not seen and not heard. You can’t feel high cholesterol or see what it’s doing to your arteries. That’s precisely why it’s worth considering before trouble arises.