High cholesterol, a condition often associated with being overweight or having an unhealthy diet, can silently affect individuals who appear slim and healthy, according to Dr. Zoe Astroulakis, a consultant cardiologist. This fatty substance builds up in blood vessels, and without symptoms, can go undetected for years, increasing the risk of heart attack, stroke, and other cardiovascular diseases, which remain a leading cause of death and disability.
Cholesterol levels are measured in millimoles per litre of blood (mmol/L). High-density lipoprotein (HDL) is known as 'good' cholesterol, aiding in its removal, while low-density lipoprotein (LDL) can accumulate in artery walls, leading to narrowed vessels and restricted blood flow. A healthy adult should aim for an overall cholesterol level of 5 mmol/L or less, with LDL no higher than 3 mmol/L and HDL above 1 mmol/L.
Genetic Predispositions and 'Skinny Fat'
Dr. Astroulakis notes that inherited conditions, such as familial hypercholesterolaemia, are a common cause of high cholesterol even in healthy individuals. Affecting approximately one in 250 people globally, this genetic disorder significantly increases the risk of heart and artery problems, leading to very high LDL levels from an early age and a risk of premature heart disease. Without genetic testing, many remain unaware until a major cardiovascular event occurs.
Even without a specific inherited condition, approximately 40–60 per cent of variations in LDL cholesterol are estimated to be inherited, with lifestyle factors contributing the rest. Individuals with close relatives who experienced early heart disease or have multiple family members with high cholesterol are advised to get tested, even if under 40.
Another factor is visceral fat, sometimes referred to as 'skinny fat' or TOFI (thin outside, fat inside). This type of fat surrounds internal organs and can disrupt cholesterol processing. Diet, particularly high-calorie intake and excessive alcohol consumption, is a primary cause, and it can also be linked to conditions like diabetes, chronic kidney and liver disease, and lupus.
Beyond LDL and HDL, Dr. Astroulakis emphasizes the importance of understanding the full lipid profile, including triglycerides, another type of blood fat that contributes to cardiovascular risk when elevated, even if 'bad' cholesterol levels are normal. This comprehensive data allows doctors to use risk calculators to estimate a person's ten-year risk of heart attack or stroke and determine appropriate treatment.
Gender and Menopause
Gender also plays a role. While estrogen provides women with some protection against heart attacks and strokes before menopause, this advantage diminishes afterward. Post-menopause, LDL cholesterol levels can rise by over 20 percent while HDL levels decrease, contributing to a surge in heart disease rates among post-menopausal women, which can catch up to men's rates within a decade. Women experiencing early menopause may face this increased risk sooner. A history of pre-eclampsia or gestational diabetes can also heighten the likelihood of later-life cardiovascular disease, underscoring the importance of early monitoring.
Physical Warning Signs
Visible signs can also indicate high cholesterol. Xanthelasma, characterized by soft, yellow, fatty lumps appearing on the eyelids, is associated with high cholesterol in about 50 percent of cases, though it can also signal diabetes or liver disease. A grey or white ring around the cornea, known as corneal arcus, is common with aging but can be a sign of high cholesterol if it appears before age 45.
Tendon xanthomas, firm lumps on the Achilles tendon and the tendons of the hands, are also commonly seen in individuals with familial hypercholesterolaemia.
Treatment Options
For those diagnosed with high cholesterol, Dr. Astroulakis highlights the effectiveness of statins. These medications significantly reduce the risk of heart attacks and strokes by 25 to 30 percent, with their benefits greatly outweighing the small risk of serious side effects. Statins work by lowering LDL cholesterol circulating in the blood, reducing plaque buildup in artery walls, and may also help stabilize existing plaques to prevent rupture, a precursor to blood clots.
Cholesterol tests are offered by the NHS to all adults aged 40 and over. Earlier or free testing is available for those with a family history of heart disease, who are overweight, smoke, or have high blood pressure. Private testing is also available at pharmacies.