High cholesterol is often thought of as a problem for people who are overweight, older or living on an unhealthy diet – but the reality is far less straightforward.
Because it rarely causes symptoms, raised cholesterol can go undetected for years, quietly increasing the risk of heart attack, stroke and other forms of cardiovascular disease – even in those who appear to be slim and ‘healthy’.
These conditions remain the leading cause of death and disability in the UK and are responsible for around 170,000 deaths each year.
Now, experts are warning that even ‘healthy’ people must be aware of their level of cholesterol – which is a fatty substance that builds up in the blood vessels.
‘Your cholesterol levels won’t automatically be “fine” because you are slim, exercise regularly and eat healthily,’ says Dr Zoe Astroulakis, consultant cardiologist from New Victoria Hospital in London.
‘You cannot tell what your blood cholesterol is without a blood test. You may have had high cholesterol levels all your life, and yet wouldn’t show any signs of it.’
But there are risk factors that could prove to be a red flag, and are a reason to get tested, according to Dr Astroulakis.
Here, she outlines the exact family history you need to watch out for, as well as the signs that have nothing to do with your weight, shape or levels of body fat.
Firstly, Dr Astroulakis says, it’s important to know how cholesterol is measured, and about the different types.
Blood cholesterol is measured in units called millimoles per litre of blood, often shortened to mmol/L.
Cholesterol is carried around the bloodstream in particles including high-density lipoprotein (HDL) and low-density lipoprotein (LDL).
A healthy adult’s overall level should be 5mmol/L or less, while their LDL level should be no more than 3mmol/L – an ideal level of HDL is above 1mmol/L.
HDL is often called ‘good’ cholesterol because it helps carry excess cholesterol back to the liver, where it can be processed and removed from the body.
LDL, meanwhile, can become lodged in the walls of the arteries. Over time, this contributes to the formation of fatty plaques, narrowing the blood vessels and restricting the flow of blood to the heart and brain.
Low levels of HDL may also make it harder for the body to clear this excess cholesterol.
So why do some people discover they have raised cholesterol despite exercising regularly, eating a balanced diet?
Often, the problem is inherited says Dr Astroulakis. ‘Familial hypercholesterolaemia is a fairly common, though underdiagnosed, inherited condition affecting approximately one in 250 people worldwide.’
Those with this genetic vulnerability have a 10 to 20-fold increased risk of developing heart and artery problems, compared to those who don’t have it.
The condition causes very high levels of LDL cholesterol from an early age and can dramatically increase the risk of premature heart disease.
Around half of male sufferers who remain untreated will go on to have a heart attack by age 50; the same is true for roughly a third of women by age 60.
Without testing, however, many people may have no idea they are affected until they have a major medical event, like a heart attack.
However, even those without the condition may have a genetic vulnerability to dangerous high cholesterol.
In fact, according to the British Heart Foundation around 40–60 per cent of the variation in LDL cholesterol is estimated to be inherited from parents, with the remaining variation a result of a combination of lifestyle factors.
Doctors say those who have close relatives who developed heart disease at a young age and/or have several family members with high cholesterol should get tested, even if they’re under 40.
Meanwhile, others could fall into the category of ‘skinny fat’ or TOFI – thin outside fat inside.
Xanthelasma can cause fatty deposits around the eyes
Despite having a slim frame, they have visceral fat around their internal organs – the most dangerous type of fat that sits around the abdomen and disrupts cholesterol processing.
The main cause is diet, with foods that are high in calories, as well as above-average alcohol intake.
Being ‘skinny fat’ can also be linked to other conditions, such as chronic kidney and liver disease, diabetes and lupus.
What’s more, Dr Astroulakis says it’s not just the headline cholesterol figure that patients should pay attention to.
‘When a cardiologist asks about your cholesterol, they are looking for more information than you might have realised,’ she says.
‘We want to know the full lipid profile, or ‘the Good, the Bad and the Ugly’, by which we mean the breakdown of the “Good” HDL-cholesterol, the “Bad” LDL-cholesterol, and your “Ugly” triglyceride.’
Triglycerides are another type of fat found in the blood and can also contribute to cardiovascular risk when levels are raised – even if ‘bad’ cholesterol is normal.
‘Knowing these data, we can put the figures into an online calculator to discover your risk score,’ Dr Astroulakis says.
The score estimates a person’s chance of having a heart attack or stroke within the next ten years and helps doctors decide whether treatment may be appropriate.
While the NHS offers cholesterol tests for all adults aged 40 and over as part of a midlife health check, those with a family history can access a free earlier test – as well as those who are overweight, smoke, or have high blood pressure.
Alternatively, you can pay for one at a local pharmacy.
Another risk factor too few are aware of, says Dr Astroulakis, is gender.
Although oestrogen appears to offer women some protection before the menopause, that advantage does not last forever.
‘It’s true that women, when compared to men, are protected against heart attacks and strokes by their circulating oestrogen levels, but only until the menopause,’ says Dr Astroulakis.
Once oestrogen levels fall, cholesterol can quickly move in the wrong direction.
‘Thereafter, LDL-cholesterol levels may increase by more than 20 per cent, while HDL-cholesterol levels decrease,’ she explains.
‘This, alongside other metabolic changes in the lead-up to the menopause leads to the sudden increase in heart disease in post-menopausal women, with heart attack rates catching up to that of men within ten years.’
Women who experience an early menopause may face this increased risk sooner.
A history of pre-eclampsia or gestational diabetes can also raise the likelihood of cardiovascular disease later in life, making early monitoring particularly important.
Although high cholesterol can lay silent for years, there are physical signs that could hint that medical investigation – and potential interventions – are warranted.
These include a change in the skin around the eyelids – technically referred to as xanthelasma – when soft, yellow, fatty lumps rise to the surface of the eye socket.
Brandon Wilson has familial hypercholesterolemia and has had four heart attacks, seven coronary stents, and a stroke before 40 as a result of his condition
About 50 per cent of cases are related to high cholesterol, but they are also seen in people with diabetes, hypothyroidism, liver disease, or other conditions that affect how fats are processed by the body.
Another warning sign in the eyes is corneal arcus, when a grey or white ring appears around the edge of the cornea. It’s a common sign of ageing, but if it appears before the age of 45 it can signal high cholesterol.
Visible signs of high cholesterol can also manifest elsewhere on the body.
Tendon xanthomas causes firm lumps over the Achilles tendon and the tendons on the backs of the hands. It is most commonly seen in those with familial hypercholesterolaemia.
For those found to have high cholesterol, there’s thankfully a treatment that’s proven to be extremely effective, and which patients mustn’t be reluctant to take, says Dr Astroulakis.
For those at genuine risk of heart attack or stroke, Dr Astroulakis says the benefits of statins are substantial.
‘They offer huge health benefits, reducing the risk of heart attacks and strokes by 25 to 30 per cent.
‘The benefits of statin therapy far outweigh the small risk of serious side-effects.’
Statins lower the amount of LDL cholesterol circulating in the blood, leaving less available to collect in artery walls.
They may also help make existing plaques less likely to rupture.
‘Not only do statins deplete circulating LDL-cholesterol levels, there is evidence that statins help prevent cholesterol plaques from rupturing – a precursor to blood clots that cause heart attacks and strokes.’
