Keen to improve your heart health? One great place to start, aside from leading a healthy lifestyle, is with an awareness of your cholesterol level. Cardiovascular disease is the leading cause of death globally. It’s a silent killer caused by various risk factors. The most typical of these includes what are known as the “three hypers”: hypertension, hyperglycemia and hypercholesterolemia. Among these three, hypercholesterolemia – the medical term used to refer to a high blood cholesterol level – is the major one involved in the genesis of heart disease and stroke.
How much do you know about cholesterol, the waxy, fat-like substance found in our blood? How does high cholesterol level affect our health? We spoke with DR NORMAN CHAN and DR ADRIAN CHEONG and asked them ten readers’ questions on the topic.
#1 “Is all cholesterol harmful to my health?”
We tend to associate cholesterol with cardiovascular disease. Yet it’s also essential for our body formation – for example, cell membrane and sex hormones are made of cholesterol. Cholesterol can be divided into “good” – that is, high-density lipoprotein (HDL) cholesterol – and “bad” – low-density lipoprotein (LDL) cholesterol. The excessive production of LDL cholesterol may cause deposition in blood vessels; the formation of plaques may then rupture or narrow the blood vessels, leading to heart attack and stroke.
#2 “If I have high cholesterol, what kind of symptoms will I experience?”
Patients with high cholesterol seldom experience obvious symptoms. Symptoms usually appear only when vascular blockage gets worse. It implies a certain level of damage has been made to the blood vessels, putting patients at an increased risk of cardiovascular diseases. People can’t identify their cholesterol levels unless a blood test is performed.
#3 “If I’m diabetic, should I pay extra attention to my cholesterol levels?”
When compared with healthy people, the risk of cardiovascular disease is higher in most diabetic patients due to the association between diabetes and cholesterol. Clinical trials found that for type 2 diabetic patients with coronary heart disease, the single most important risk factor is high LDL cholesterol level rather than high glucose level. Cholesterol molecules in diabetic patients are smaller and denser, making them accumulate easily on the artery walls and cause blockage. That’s why it’s highly recommended that diabetic patients maintain a healthy cholesterol level to reduce the risk of cardiovascular diseases.
#4 “What is my optimal cholesterol level?”
There is no universal cholesterol level that suits everyone. The optimal LDL cholesterol level varies with different risk groups. For lower- risk groups without known cardiovascular risk factors, they should keep the level below 2.6 mmol/L. In the high-risk group, including those with high blood pressure and diabetes, the LDL cholesterol level should be kept below 1.8 mmol/L. For very high-risk groups including patients with cardiovascular diseases and those who have had bypass grafting or stenting, the LDL cholesterol level should be reduced to less than 1.4 mmol/L.
#5 “If I’ve had a stent placed, do I need to control my cholesterol levels after the procedure?”
Some people who have suffered from cardiovascular diseases, such as stroke or heart attack, may have received percutaneous coronary intervention (that is, treatment to keep the narrowed arteries open with stents). This procedure is effective in treating cardiovascular diseases, but not high cholesterol. If the cholesterol levels aren’t well-managed after the procedure, then yes, there’s a possibility that patients may still suffer from high cholesterol. This group of patients should control the LDL cholesterol level to 1.4 mmol/L or below, otherwise they may end up having another operation in five years.
#6 “Can modifying my lifestyle be sufficient on its own to reduce cholesterol?”
Lifestyle modification plays a role in cholesterol reduction prior to the need for treatment. However, only about 20 percent of cholesterol is absorbed from the diet, while 80 percent are produced by the liver. It may take a long time to make a significant difference to the LDL cholesterol level, if only lifestyle modification is adopted. Especially for the high-risk group and very high-risk group, diet modification may not be enough to reduce cholesterol to a large extent and reach the target level. The combo of drug treatment and lifestyle modification may be more effective in lowering cholesterol level in this occasion.
#7 “Is cholesterol level the only factor I need to monitor?”
Cholesterol level is one of the typical risk factors for cardiovascular diseases, but there are some other risk factors as well. Lipoprotein(a), or LP(a), has a similar molecule structure to LDL cholesterol, and its production in our body is genetically relevant. Recently, some young patients with cardiovascular diseases aged between 30 and 40 were found to have high LP(a) levels and severe coronary plaques, though not many other typical risk factors were present.
Fatty liver is another important risk factor. It’s associated with PCSK9 protein levels that link up with the LDL cholesterol level. Some newly diagnosed diabetic patients receive high doses of statins, but their cholesterol levels are still beyond the target level. This may be caused by fatty liver. Monitoring of LDL cholesterol level, LP(a) level and fatty liver could provide a more comprehensive picture of cardiovascular risk management.
#8 “What are the treatment options for cholesterol and lipoprotein(a) reduction?”
The available cholesterol-lowering agents are divided into oral drugs and injectables in general. Statins are a class of oral drug with a fixed and relatively frequent dose schedule. Though they are commonly used for cholesterol reduction, they may not be effective in people with genetic resistance to statins; even when a high dose of statins is prescribed, these patients may not be able to achieve the target LDL cholesterol level.
In general, side effects may increase with the dose of statins. Some patients experience muscle pain and find they need a longer time to recover after exercise; others even suffer from rhabdomyolysis (a life-threatening condition of muscle breakdown). Also, it can be tricky for patients leading a busy life to take the medication on time every day. The introduction of injectables with a less frequent dose schedule, including PCSK9 inhibitors and siRNA therapy, may be an alternative option for these patients.
#9 “If I don’t keep up my medications, how will that affect my disease management?”
Regular treatment is crucial to maintain optimal cholesterol levels. Most treatment options require patients to take medication frequently, even once a day. While it may be challenging for patients to be compliant to the treatment with a frequent dosing schedule, it’s particularly dangerous for the very high-risk group if they’re not taking medication when they should. Their cholesterol levels may rise again, increasing the risk of cardiovascular diseases.
Nowadays, new injectables targeting the PCSK9 protein such as siRNA therapy is introduced for patients who fail to reach the optimal cholesterol level with oral drugs. By blocking the activity of PCSK9 proteins, PCSK9 inhibitors increase the clearance of cholesterol. The siRNA therapy reduces the cholesterol through interfering with the production of PCSK9 proteins to allow more functioning cholesterol receptors on the surface of liver cells. This enhances the recycling capacity of the liver, so that more cholesterols can be absorbed and removed from the blood. Patients prescribed with the siRNA injectables need to receive the injection every six months, which acts as an alternative option.
#10 “How can I identify if the symptoms I’m feeling are side effects of taking the medications?”
When taking statins, as an example, side effects such as fatigue and muscle weakness are not specific. Therefore, it’s hard for patients to identify the real cause of presenting symptoms. If they do experience these symptoms, it’s recommended to seek consultation from a doctor instead of stopping the medication themselves. Otherwise, the cholesterol level may go up without medication control.
As high cholesterol level is harmful to cardiovascular health, everyone should maintain an optimal LDL cholesterol level based on the risk group they belong to. Effective treatment and high compliance are essential for patients with high cholesterol levels. Patients should strictly follow the instructions of doctors for treatment and check-ups to lower the risk of cardiovascular diseases. The lower the cholesterol level, the lower risk there is of cardiovascular disease. Besides, patients should maintain a habit to check cholesterol levels regularly for early detection and treatment.
Dr Norman Chan is a Specialist in Endocrinology, Diabetes & Metabolism and Dr Adrian Cheong is a Specialist in Cardiology. This article is supported by Novartis Pharmaceuticals (HK) Limited. HK2207257451
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