To cut or not to cut cholesterol
According to Cholesterol Skeptics, there is precious little evidence that a longer life results for those millions of people who for years have dutifully taken their drugs and endured cholesterol-reducing diets. In fact, a number of trials have found that, even though the number of deaths from heart disease does fall when cholesterol is reduced by a range of means among patients in primary care — that is, at family doctor level — there is often an increase in the overall death rate from other causes.
Rebecca Warburton, a professor at the University of Victoria in Canada, reviewed studies of statins and concluded: “Statins in primary prevention have not consistently reduced the incidence of myocardial infarction (heart attack) or stroke. Other studies have even found that over the age of 50, reducing cholesterol increases the death rate.” The notion that cholesterol is linked to heart disease goes back to the middle of last century, along with the idea of bringing cholesterol levels down with a low-fat diet to protect the heart. But both of these ideas have been strongly challenged. For example, plenty of studies show that only 50 per cent of people who develop heart problems have high cholesterol, while a study in the BMJ in 2001 found no link between changing fat in the diet and heart disease. In Sweden official advice is to reserve statins largely for secondary care. If pushed, experts in favour of aggressive cholesterol reduction may well admit that the value to women is less clear.
That is because, although women tend to have higher levels through life, they develop heart disease 15 to 20 years later. An increasing number of doctors are putting post-menopausal women on statins to protect their hearts now that HRT has been discredited. Is this wise?
A resounding “no’’ was the answer from an analysis of five statin trials conducted by a team of researchers at the University of British Columbia (UBC) in Canada and published last year. Stressing that only 28 per cent of the participants were women, the team concluded: “The results do not support the use of statins by women without heart disease.’’ The UBC group also raised new queries about side effects. Statins are generally described as safe and well tolerated. But the same report concluded that although patients on statins had a 1.4 per cent lower rate of heart attacks, this was cancelled out by a 1.8 per cent rate of “serious adverse events associated with the drug’’, including cancer. That, they say, is almost certainly an underestimate since only two of the trials provided details of any serious side effects. The researchers said they had asked the drug producers for the missing data but received no reply.
To an outsider what is curious about this debate is that both sides are using the same data; much of the disagreement is based on how you interpret it. Two recent developments
have given a big impetus to the Skeptics. The first is the huge surge in the popularity of the Atkins diet. So far the results seem to show that eating a diet high in fat doesn’t automatically result in a rise in cholesterol. This strikes at the roots of the cholesterol hypothesis. Another aspect of the argument is that a diet high in carbohydrates, especially refined carbohydrates such as sugar, damages arteries in the long run. A key factor in developing heart disease, say the Skeptics, is inflammation. This is the defensive reaction produced by the body when it feels under attack. In the past two years, two major studies have found that the amount of inflammation in your body is a better indicator of your heart-attack risk than your cholesterol level. Inflammation is measured by something called C-reactive protein (CRP). Some claim such findings make the cholesterol hypothesis redundant. This could supply an answer to the question raised by the Skeptics’ challenge: If cholesterol reduction isn’t that beneficial, why do the drugs reduce the number of heart attacks? Probably, say the Skeptics, by reducing inflammation.If this turns out to be what is going on, and trials are under way to test the idea, this seems likely to shunt cholesterol reduction into a small corner of the overall picture of heart disease and allow statins to be marketed as “inflammation fighters’’. Other ways of reducing your C-reactive protein level include stopping smoking, losing weight and exercising.
The cholesterol hypothesis is unlikely to be abandoned in a hurry, given the weight of financial and political muscle behind it. But the Skeptics have raised questions that could ultimately have an impact on the way we think about heart disease.