No Link Between Cholesterol and Heart Disease, Review Claims

Heart disease is the leading cause of death in the UK. Conventional thinking is that having high LDL cholesterol levels increases your risk of dying of cardiovascular diseases, such as heart disease.

However, a new review has gathered evidence from previous observational studies to find out whether LDL cholesterol (so-called "bad cholesterol") was linked with mortality in older adults aged over 60.

 

Researchers analyzed 30 studies. 28 studies looked at the link with death from any cause. Twelve found no link between LDL and mortality, but 16 (representing 92% of individuals in the review) actually found that lower LDL was linked with higher mortality risk – the opposite to what was expected.

 

Only nine studies looked at cardiovascular mortality link specifically – seven found no link, and two found the opposite link to what was expected.

 

The study by Ravnskov et al. was carried out by researchers from the University of South Florida, the Japan Institute of Pharmacovigilance and various other international institutions in Japan, Sweden, UK, Ireland, US and Italy. Findings are published in the peer-reviewed BMJ Open journal.

 

Four of the study authors have previously written book(s) criticizing "the cholesterol hypothesis". It should also be noted that nine of the authors are members of THINCS – The International Network of Cholesterol Skeptics. This is described as a group of scientists who "oppose…that animal fat and high cholesterol play a role [in heart disease]".

 

The researchers did not pool the results of the individual cohorts in a meta-analysis, but gave a narrative summary of the findings.
They concluded that: "High LDL-C is inversely associated with mortality in most people over 60 years", and state that their finding contradicts the cholesterol hypothesis: that cholesterol, particularly LDL, causes fatty build-up in the arteries.

 

This research suggests that – contrary to common belief – LDL cholesterol is not as "bad" as may be thought, and higher levels are not linked to all-cause or cardiovascular mortality.

 

However, before accepting this as fact, there are many important limitations to consider – both to the review and the included studies – many of which the review authors themselves acknowledge.

 

The findings of this review and possible explanations will need to be explored further, but for now this review doesn't provide solid evidence that high LDL cholesterol is good for you, or that statins are of no help. People given statins should continue to take them as prescribed.

 

There is currently no comprehensive body of evidence that contradicts current official advice on saturated fat consumption – which recommends no more than 30g of saturated fat a day for men and 20g for women.

 

Some experts have reacted to the findings of this review. Professor Colin Baigent, Professor of Epidemiology & Deputy Director of the Clinical Trial Service Unit (CTSU), University of Oxford, said: “This study has a number of serious weaknesses and, as a consequence, has reached completely the wrong conclusion. In fact, we know that cholesterol is just as important as a cause of heart disease in older people as it is in the young. We know this because of the evidence from all the randomized trials of statin therapy, which collectively have studied substantial numbers of older people, and which have shown very clearly that people benefit just as much from reducing their cholesterol when they are in their 70s as when they are younger.”

 

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, commented that the results were “not surprising because, as we get older, many more factors determine our overall health, making the impact of high cholesterol levels less easy to detect.”

 

“In contrast, the evidence from large clinical trials demonstrates very clearly that lowering LDL cholesterol reduces our risk of death overall and from heart attacks and strokes, regardless of age. There is nothing in the current paper to support the authors’ suggestions that the studies they reviewed cast doubt on the idea that LDL cholesterol is a major cause of heart disease or that guidelines on LDL reduction in the elderly need re-evaluating.”

 

Dr Tim Chico, Reader in Cardiovascular Medicine & consultant cardiologist, University of Sheffield, said: “There have been several studies that tested whether higher cholesterol increases the risk of heart disease, by lowering cholesterol in elderly patients and observing whether this reduces their risk of heart disease (for example the PROSPER study). These have shown that lowering cholesterol using a drug does reduce the risk of heart disease in the elderly, and I find this more compelling than the data in the current study. I am surprised the authors of this study do not refer to such trials, which tends to make their own paper disappointingly unbalanced.”