About 10 percent of the population is at particularly high polygenic risk – the combined effect of several genes that influence a person’s susceptibility to cardiovascular disease. A family history of early heart attack, stroke, bypass surgery, or stenting can sometimes be a clue to this hereditary risk, especially when these events occur in men before age 55 or in women before age 60.
Some people also have high LDL levels from birth, a condition known as familial hypercholesterolemia, which affects about one in 250 people. It is often diagnosed late in life or only after a heart attack. This is why I think having your cholesterol levels checked regularly – perhaps with a blood test every five years starting in your 30s – can be particularly helpful.
Familial hypercholesterolemia results in cumulative exposure to high cholesterol. Think of it like smoking: the risk depends not only on how much you smoke, but also on how long you smoke. A person with an LDL level of 5 mmol/L may have had it for five years, while a person suffering from familial hypercholesterolemia may have had the same level since birth. So the length of time your cholesterol level is high matters as much as the level itself.
Why the same LDL level does not mean the same thing for everyone
Doctors use clinical risk calculators to estimate a patient’s risk of developing cardiovascular disease – such as a heart attack or stroke – over the next 10 years. But age has a major influence on these calculations, meaning a younger person may be at low short-term risk despite having significant risk factors.
A 40-year-old woman, for example, may have a very low 10-year risk due to her age. This does not mean that she does not have underlying atherosclerosis or significant risk during her life. A person with a few birthdays older may be at much higher risk over their lifetime, even if their underlying risk factors have not suddenly changed. This explains why there is no universal “safe” number for cholesterol.
It’s also important to note that the average LDL level in a person having a heart attack is not particularly high, being around 3.2 to 3.4 mmol/L. Many people who have a heart attack do not have a dramatic increase in their cholesterol levels. Their level may simply be too high for their individual vulnerability.
What about statins?
There is a common misconception that doctors prescribe statins to anyone with high cholesterol. This is not true. Statins are prescribed when a person’s overall cardiovascular risk is high enough that lowering LDL cholesterol will reduce the risk of heart attack or stroke.
Today, it is not appropriate for a doctor to simply say to a patient, “Your cholesterol is high, take a statin.” » A good doctor should explain why a statin has been recommended and what risk it aims to reduce. No one should feel obligated to take medication; rather, they should be provided with clear and meaningful information so that they can make an informed decision.
Lifestyle choices can also improve cholesterol levels. Consuming more fiber-rich foods, such as oats, seeds, legumes, lean meat and fatty fish, while reducing your intake of processed foods, saturated fats, excess dairy and red meat, can have a significant impact on your cholesterol levels.
Midlife Checkups You Shouldn’t Ignore
To measure your overall risk of heart disease, make the most of your NHS mid-life health check. This includes a cholesterol check, blood pressure measurement and assessment of your risk of diseases such as diabetes. Also consider getting your Lp(a) tested once and factoring it into your broader family history. If you want to get an idea of your long-term risk, try the QRISK lifespan calculator. Taking all of these measurements into account is much more useful than focusing only on total cholesterol.
Don’t just focus on 10-year risk: Understanding your risk over your lifetime can help you make lifestyle changes before more serious problems develop. Know your numbers from the start, understand what they mean in context, and don’t wait for symptoms before thinking about cardiovascular risk.
As told to Ella Nunn
Professor Kausik Ray is a world-renowned preventive cardiologist and Professor of Public Health at Imperial College London.
Gn Health
