Flawed cholesterol study makes headlines
A controversial study has argued that if you have a high LDL (bad) cholesterol level when you are aged over 60, you will live longer, there is no increased risk of cardiovascular disease and that statins will have little effect. But can we trust these bold claims?
The researchers, led by Dr Uffe Ravnskov at the University of Lund, Sweden, looked at 19 existing studies which considered the association between ‘bad’ LDL cholesterol levels and the overall risk of death in people aged over 60. They concluded that 92 percent of people with a high cholesterol level lived longer, and called for a re-evaluation of the guidelines for cardiovascular prevention, “in particular because the benefits from statin treatment have been exaggerated.”
Cholesterol is essential for your body to work, although too much ‘bad cholesterol’ (called low-density lipoprotein or LDL) can lead to fatty deposits building up in your arteries. These fatty deposits can increase your risk of developing conditions such as coronary heart disease, heart attack and stroke.
Statins are drugs that lower your body’s cholesterol level. They work by reducing the production of cholesterol in the liver and therefore reduce your risk of heart disease.
The total number of people involved in the study was nearly 70,000, but only 9 of the 19 studies actually included deaths from heart and circulatory disease.
Moreover, two-thirds of the total number of participants in this new analysis are from one study (Bathum et al 2013). This study found that higher cholesterol (total, HDL, or LDL) in people aged 50+ was associated with a lower all-cause mortality. That study also showed that taking a statin prescription provided a significant survival benefit, regardless of age, whereas the researchers in this new analysis are using it to argue against statins.
They relied on limited, aggregated and inconsistent information …an approach liable to bias
BHF Professor of Epidemiology
Furthermore, the research, published in the BMJ Open journal, has been deemed unbalanced due to what John Danesh, BHF Professor of Epidemiology said was “crude study methods”. This is because their analysis "relied on limited, aggregated and inconsistent information from published sources, an approach liable to bias.”
Similarly Colin Baigent, of the University of Oxford, has described the study as reaching “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.”
The authors themselves said that “We may have overlooked relevant studies as we only searched PubMed” (an online search for medical publications), and they may have excluded studies that evaluated LDL-C as a risk factor for death, if the study did not mention it in the title or abstract. “We may have overlooked a small number of relevant studies because we only searched papers in English,” they added.
Dr Tim Chico, a consultant cardiologist at Northern General Hospital in Sheffield, said there are several studies that has shown lowering cholesterol using a drug does reduce the risk of heart disease in the elderly. He said: “I am surprised the authors of this study do not refer to such trials, which tends to make their own paper disappointingly unbalanced.”
Evidence from large clinical trials demonstrates very clearly that lowering LDL cholesterol reduces our risk of death overall
Professor Jeremy Pearson
BHF Associate Medical Director
Some of the participants in the study with high cholesterol may have started statins during the study, and therefore their high life expectancy could be due to them being on statins. Similarly, some of them may have started a healthy diet during the study, and this could have increased their life expectancy.
At least five of the study authors have previously written books questioning the links between cholesterol and heart disease. The lead author Dr Uffe Ravnscroft, has written a book called ‘The Cholesterol Myths: Exposing the Fallacy that Saturated Fat and Cholesterol Cause Heart Disease’. Another of the authors, London cardiologist Dr Aseem Malhotra, is a prominent campaigner against statins.
The BHF View
Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, said: “As we get older, many more factors determine our overall health, making the impact of high cholesterol levels less easy to detect.
"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.”
The media coverage
The story was covered by the Daily Mail, Guardian, Independent, Telegraph, BBC Radio Four and others. The Daily Mail headline ‘Statins 'may be a waste of time': Controversial report claims there's NO link between 'bad cholesterol' and heart disease’ did at least include the word ‘controversial’, rather than present the evidence as fact, while The Times’ headline Bad cholesterol ‘helps you live longer’ was arguably less balanced.
Much of the news coverage did show the controversy that the report has caused, although in some cases this was not mentioned till most of the way through the article.
It is important that people at high risk of a heart attack or stroke take their prescribed medication. Individuals can assess their cardiovascular risk and find information about how to reduce it using the Heart Age Tool, developed by the BHF, Public Health England, NHS Choices and Joint British Societies. If someone is unsure about their heart medicines, they can speak with their GP or contact our Heart Helpline on 0300 330 3300.