For decades people have been told to reduce their intake of cholesterol. Yet, this fatty substance has many important functions in the human body. In fact, cholesterol is vital for good health.
On the other hand, we are told that having high total cholesterol in the blood is a primary cause of narrowing of the arteries and cardiovascular disease. The so called cholesterol hypothesis. Cardiovascular disease includes heart disease, stroke, heart failure and heart attack. So, when a doctor finds high cholesterol levels, cholesterol lowering drugs, statins are recommended.
However, there are several reasons to question this approach. Research published in 2016, in the British Medical Journal, suggests that having high cholesterol may not be harmful for people over 60. In fact, the opposite might be true.
The researchers argue that evidence from Japanese studies suggests that high total cholesterol is not a risk factor for stroke. Not only that, but when these studies looked at total cholesterol levels in relation to death rates from all causes, people with lower total cholesterol had a higher risk of death.
However, the evidence is not so straight forward. The researchers go on to describe a recent meta-analysis of studies that does suggest an association between total cholesterol and increased risk of death from cardiovascular disease. But, deeper analysis shows that the association reduced with increasing age. In fact, the link between total cholesterol and cardiovascular disease risk, was minimal after the age of 80. The researchers in the BMJ study explain that since narrowing arteries and cardiovascular disease mainly affect older people, if the cholesterol hypothesis were true, that link should be at least as strong in the elderly.
Could it be that total cholesterol is not the problem? After all, we know that there are different types of cholesterol. The so called ‘good’ cholesterol or high density lipoprotein cholesterol (HDL cholesterol) and ‘bad’ cholesterol or low density lipoprotein cholesterol (LDL cholesterol). If total cholesterol is not harmful, what about LDL cholesterol?
Is LDL cholesterol a risk factor for older people?
The BMJ study assessed data from several trials, involving a total of over 68,000 people. They wanted to see if there was a link between LDL cholesterol levels and risk of death in older people. The data suggests that for these people, having high LDL cholesterol in fact reduces the risk of death from all causes. Whilst deaths from cardiovascular disease were either reduced in people with higher levels of LDL cholesterol, or there was no link.
This finding has been discussed before, with a possible explanation. The theory is that the increase in deaths associated with lower cholesterol levels is because having a serious disease lowers cholesterol shortly before death. However, the researchers in the BMJ article explained that even in the studies that excluded terminally ill people, they still found either no association between LDL cholesterol and death from all causes, or, lower LDL cholesterol was associated with a higher risk.
So, the research shows that for people over 60 there is either no link between LDL cholesterol and risk of death from all causes, or having higher LDL cholesterol confers a lower risk of dying. In other words, it appears that this research supports the direct opposite of the cholesterol hypothesis for people over 60. For people who are interested in healthy ageing this might be an important fact to know.