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cholesterol

Cholesterol Myths

The commonest cause of death and disability around the globe is cardiovascular disease.

It is estimated that around 17 million people die on a yearly basis from some form of cardiovascular disease.

The commonest cause of cardiovascular disease is atherosclerosis which is the progressive build-up of fat, inflammatory tissue and calcification within the walls of an artery. If you think about a doughnut, the artery is very similar. The blood flows through the channel but all the action is happening in the wall. From very early on in life, fat, inflammatory tissue and subsequently calcium build-up in the wall of the arteries without causing a blockage. This process may take decades before the fatty plaque that has formed suddenly ruptures to cause an acute vascular event such as heart attack or stroke.

There is no doubt that LDL cholesterol is central to this process but it is not that simple. For many years, we have been told that LDL is bad and HDL is good. Here is where size is important! Both LDL and HDL can be divided into small and large particles. The large particles are typically good, whereas the small particles are bad.

Simplistically, small LDL puts fat into your arteries where as large LDL is an important component of cellular metabolism, building healthy brain function, is the basic ring for steroid metabolism, bile salt and vitamin D metabolism.

Small HDL is pro-inflammatory & is intimately involved in the atherosclerotic process in the artery wall. Large HDL removes fat from the arteries. Thus, purely considering the basic cholesterol profile does not give the entire story. The sub-fractions of cholesterol can be measured but typically, if you have elevated cholesterol, elevated HDL cholesterol and low triglycerides, you have predominance of large LDL and HDL and therefore an healthy pattern. Whereas if you have an elevated triglyceride and low HDL, this typically reflects small LDL and HDL which is the pattern that promotes the build-up of fat in the walls of your arteries.

Two large recent trials have also questioned the hypothesis that saturated fat promotes heart disease. A large meta-analysis from Cambridge University in the UK involving 650,000 people showed no link between saturated fat and heart disease and this was also suggested by the PURE study which looked at 220,000 people over nine years in 50 different countries showing a 14% reduction in all cause death and cardiovascular disease in people with the highest intake of saturated fat.

Basically, I do not treat an elevated cholesterol, rather I assess cardiac risk. I perform a coronary calcium score which is a CT scan that does not involve injections or dye and assesses the build-up of fat in the walls of the coronary arteries using calcium as a surrogate marker. The more calcium, typically the more fat, putting you at higher risk. A recent presentation at the European Society of Cardiology meeting in 2019 showed clearly that if the coronary calcium score was below 100 over the age of 50 without a prior history of cardiovascular disease then statin therapy to lower cholesterol is of no benefit.

Thus, before you are commenced on statin treatment it is vital you have a full and accurate assessment of your cardiovascular risk. In my practice I typically use a comprehensive risk calculator that also incorporates coronary calcium scoring.

In 2013, Dr Maryanne Demasi presented a catalyst program known as “The Heart of the Matter”. In this program which was in two parts, two key messages were delivered, both of which placed Dr Demasi in a very precarious position and, in reality, ruined her career as a medical journalist for the public broadcaster in Australia, the ABC.

The two key messages she delivered were that firstly there was a questionable link between saturated fat intake and heart disease. In the second episode, (and this was what really placed her into hot water), Dr Demasi dared to suggest that statin drugs to lower cholesterol were being over prescribed. The National Heart Foundation and many experts in cardiology around Australia damned her message saying it was irresponsible and that many people would die as a consequence of starting to consume saturated fat and also ceasing their vital statin drugs.

Despite these claims being made by the conservative groups involved, there was certainly no increase in cardiac deaths, with the only real death being the truth and Dr Demasi’s career.

Although, still in hot dispute in the nutritional world, the latest evidence from Cambridge University and also the extensive PURE trial suggest that the link between saturated fat intake and heart disease was spurious at best and possibly, especially from the PURE data showed a modest benefit for people with a regular intake of saturated fat in regards to risk of death and cardiovascular disease.

The second key point, which cause most of the furore, was the extraordinary suggestion that statin drugs are being over prescribed throughout the world. Statin drugs, also known as HMG CoA reductase inhibitors, have been used universally since the 1980s with absolute proven benefits in people with established heart disease. But, there is still significant controversy as to their use in patients at lower risk. Lipitor (Atorvastatin) is the biggest selling drug in the world.

In Australia alone, there are around 19 million prescriptions written per year by doctors for statin drugs. In 2013, I agreed entirely with Dr Demasi that although there were a significant number of people who would benefit from statin therapy, in the vast majority of cases these drugs were being over prescribed for people where they were not necessary.

Firstly, let me make the point that I do not treat cholesterol, rather, I treat risk. Over the past 20 years we have had very accurate risk prediction tools that allow us to estimate an individual’s 10 year risk for a vascular event. Many of these tools do not incorporate coronary calcium scoring which has been shown beyond a doubt over this time to be the most accurate predictor for cardiac risk. The prediction tool I use in my practice not only incorporates the standard risk factors for heart disease i.e. high cholesterol, hypertension, history of cigarette smoking, diabetes or prediabetes and family history but also uses the coronary calcium score.

Coronary Calcium scoring uses Computed Tomography, specialised X-ray equipment, to show pictures of the coronary arteries and determine the presence and extent of calcified plaque inside these vessels. The build up of plaque in the coronary arteries, which supply blood to the heart muscles, is an indicator of atherosclerosis or Coronary Artery Disease (CAD). The findings on the cardiac CT are expressed as the coronary calcium score (see box below), which I had introduced in Australia in conjunction with the Sydney Adventist Hospital in 1999 and is now accepted the world over. The great thing about coronary calcium scoring is that it provides a historical picture of the coronary arteries, which is a surrogate marker for the accumulation of fat in the arteries over the decades up to the point of scanning. It helps to assess the risk of developing coronary artery disease in a person.

As per the coronary calcium scoring, statin therapy should be prescribed if a person has a score that places them in the 75th percentile of risk. For example, if a 50-year-old male has a coronary calcium score above 50, this is already significant atherosclerosis for such a young age. However, if a 70 year-old has a coronary calcium score of 150, this is below the normal average for that age and should be ignored.

The coronary calcium scoring ranking:

Zero Lowest cardiac risk (Predicted 10 year risk is only 1 per cent which is much less than the majority of the population.)
1-10 Trivial calcification
10-100 Mild Calcification
100 – 400 100 – 400
> 400 severe calcification (predicts around a 50 per cent ten year risk, which makes it a much stronger risk predictor than cholesterol levels, blood pressure, diabetes and cigarette smoking)

While many cardiologists would conventionally order an intravenous CT coronary angiogram, the angiogram is not the best screening test for heart disease and has no proven benefits over the less expensive, typically less radiation and totally non-invasive coronary calcium score, even though it uses the same technology.

There are (as in all aspects of medicine) disputes over what is low, medium and high risk but it is my view that
1) Below a 7.5% predicted 10 year risk should be considered low.
2) 7.5 to 15% 10 year projected risk should be considered medium or intermediate.
3) Above 15 to 20% 10 year predicted risk should be considered high risk.
Two key studies published over the past two years, in my opinion, have clearly answered any disputes there are around cholesterol therapy. The first published in the Journal of the American College of Cardiology 2018;72 (25): 3233 by Villines et al, clearly demonstrated that if your coronary calcium score was below 100 in people over the age of 50 without heart disease, statin drugs were of no value.

Two key studies published over the past two years, in my opinion, have clearly answered any disputes there are around cholesterol therapy. The first published in the Journal of the American College of Cardiology 2018;72 (25): 3233 by Villines et al, clearly demonstrated that if your coronary calcium score was below 100 in people over the age of 50 without heart disease, statin drugs were of no value.

The second study published in the Annals of Internal Medicine, January 1st 2019, Yebyo et al showed clearly that if your 10 year predicted risk for a cardiovascular event was below 15% then statin drugs were of no value suggesting the potential harm of long-term therapy outweighed the benefits.

There is not much dispute in patients who have already had a heart attack, stent or coronary bypass grafting that statin drugs do offer a long-term potential benefit. Thus, the answer is very simple. You do not take a statin drug purely because your cholesterol is elevated but do take the drug if you already have established heart disease or a predicted 10 year risk greater than 15%.

Why not just take statins purely as an extra insurance against heart disease, even if you are at low risk? The answer here is very clear in that statins have a profound effect on a major metabolic pathway in the body i.e. cholesterol production. Cholesterol is a vitally important component of many aspects of metabolism. Although the short-term data i.e. less than 10 years show reasonable overall benefits in randomised controlled clinical trials, in the real world where I practice, I see many people with subtle and not so subtle side-effects from the long-term ingestion of statin therapy.

It is estimated in the randomised controlled clinical trials that less than 5% of people suffer muscle problems defined as muscle pain with elevated CPK greater than three times normal. In my practice, I would suggest that 20% of people suffer muscle pain, stiffness, weakness, cramping and in some cases even loss of muscle bulk known as atrophy with most of the symptoms markedly improving once the statin drugs are ceased, regardless of CPK levels.

I personally do not prescribe the fat soluble statins, atorvastatin & simvastatin (i.e. Lipitor & Zocor), as it is my belief that they cause more long-term side-effects. 20% of people, especially who take fat soluble statins, develop problems with memory, concentration, fatigue, depression, irritability and poor sleep, Which, in my view, are less common, although still may occur, in patients who take rosuvastatin and pravastatin (Crestor & Pravachol), the water soluble statins.

There is some effect on the liver from all of these drugs but I’m not sure this is clinically relevant, in most cases. There is also a variable increase in the risk for Type two diabetes but it appears that this is only in people who are born with the insulin resistant gene which does occur in 30% of Caucasians, 50% of Asians and close to 100% of people with darker skin.

It is also my clinical experience that around one in 10 people cannot tolerate statins because of all of the above issues and at times other less commonly reported side-effects such as gastrointestinal upset and peripheral neuropathy.

The first line of the Hippocratic Oath is “First do no harm”. An assessment of a person’s cardiovascular risk is a rather simple procedure involving a good clinical history, regularly performed blood tests and a coronary calcium score. An accurate 10 year predictive risk can be calculated. All people, regardless of risk, should be following the five keys of being healthy (which is around 80% of anyone’s management) including quitting all addictions, cultivating a healthy 7 to 8 hours sleep habit, sensible nutrition which is basically eat less & eat more natural food, 3 to 5 hours of testing exercise per week and striving as much as possible for happiness, peace and contentment.

The decision for long-term drug therapy should not be based on one number in a blood test but on a more comprehensive accurate assessment of long-term risk. Until this straightforward message gets through to the medical profession and the public, we will continue to see the over-prescription of medications. Tragically we are continuing to see the under prescription of lifestyle modification which is not negotiable for everyone living in the modern world.

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