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Risk Factor


Lewis Jones

Skeptical Briefs Volume 5.1, March 1995

In London, there is a digital mechanism that changes its display every minute. (Call it the Bell Prompt if you like.) When (and only when) the display shows the figures “00” (which is once every hour), a large hammer whacks the 13 1/2-ton bell in the tower of the Houses of Parliament, and Big Ben sounds out the hour.

Some cause-and-effect sequences are straightforward. Some are more complex. And some are misinterpreted by those who should know better. For a bizarre example of this last phenomenon, I offer you the health activists (variously known as health Leninists, health fascists, and other even less complimentary terms).

When coronary heart disease (CHD) became the latest media bogeyman, the alarmists were keen to tell us all what to do and what not to do. Unfortunately, they were aided by the epidemiologists, who were looking for something else to occupy their attention, now that infectious diseases were becoming so much less common. I say “unfortunately” because the epidemiological model is the wrong one to use. It is the clinician who pinpoints cause and effect by noting and manipulating changes in the individual. The epidemiologists set about comparing entire countries.

There are countless similarities and differences between one country and another, so it’s not surprising that the list of things held in common by CHD sufferers across the world quickly became a long one. By now, there are about 300 of these poorly named, so-called risk factors. They include snoring, baldness, not having siestas, extramarital sex, not keeping appointments, not eating mackerel, having English as a mother tongue, not being a Mormon, slow beard growth, no garlic, and having an intelligent wife. They also include the interesting pair: too much milk, and too little milk.

You might expect that any rational thinker would be able to distinguish between a correlation and a cause. Otherwise the possession of a driving license would have to count as a “risk factor” for a fatal car accident, and learning to swim would be a “risk factor” for drowning. Nevertheless, an entire health-alarm industry has fallen in love with the association game. The belief seems immune to disproof. James McCormick and Petr Skrabanek gathered together the results of all the major intervention trials, and published the resulting tables in the medical journal The Lancet (Oct. 8, 1988). The various interventions manipulated diet, smoking, blood pressure, exercise, and reducing weight, and covered 828,000 man-years. “This summary shows no experimental evidence to support the notion that intervention programs prevent coronary heart disease or reduce overall mortality. . . . Despite this considerable body of evidence, which shows no benefit for intervention, many have interpreted the results as supportive of their wishful thinking.” This review, they say “provides no data to justify the time, energy, and money which are being devoted to this crusade.”

One of the favorite villains right now is cholesterol. Most of the public had never heard of it before the present hit list was drawn up, but now many of them are altering their entire lifestyle and eating habits trying to avoid it. This is in spite of all the evidence showing the pointlessness of any such measures. The result produced by 115,176 man-years of observation was that “lowering cholesterol by drugs did no good and may have done harm.” The same applies to altering cholesterol by diet. In Sweden, for example, coronary deaths in middle-aged men were rising while the risk factors were falling. In a number of countries, death rates for men and women are moving in opposite directions, in spite of the fact that they eat the same foods. In fact, most people with heart disease have a normal cholesterol level.

Skrabanek summarizes evidence presented in the British Medical Journal and The Lancet: “Blood cholesterol for practical purposes has no predictive value for the risk of future heart attack in the individual, and manipulation of blood cholesterol with diet or drugs has no effect on overall mortality, though it may significantly increase the risk of cancer death.”

Do you really want to turn over your life to the heath zealots? G. S. Myers has put together this composite picture of someone with a low risk of CHD: “. . . an effeminate municipal worker or embalmer completely lacking in physical or mental alertness and without drive, ambition, or competitive spirit who has never attempted to meet a deadline of any kind; a man with poor appetite, subsisting on fruits and vegetables laced with corn and whale oil, detesting tobacco, spurning ownership of radio, television, or motorcar, with full head of hair but scrawny and unathletic appearance, yet constantly straining his puny muscles by exercise. Low in income, blood pressure, blood sugar, uric acid and cholesterol, he has taken nicotinic acid, pyridoxine, and long-term anti-coagulant therapy ever since his prophylactic castration.”

All this health advice is not the work of clinical or medical researchers, who know better, but is issued by “health committees,” who vote their list of recommendations into existence. Their unstated motto appears to be (in Skrabanek’s words): “If it is delicious, proscribe it; if it is bland, prescribe it.” K.A. Oster, in Medical Counterpoint, warned that these recommendations, “with wasteful neglect of nutritious foods, such as butter, eggs, whole milk, cheeses and beef, borders on irresponsibility and smacks of medical quackery.”

Another result of “riskfactormania” is that city streets are often littered with joggers, who seem unaware of the most common cause of death among joggers—coronary heart disease. The American cardiologist Henry Solomon estimates that every year about 40,000 Americans drop dead while exercising “for their health.”

Perhaps I should now confess that the Bell Prompt I mentioned in the beginning was the digital watch on my left wrist. In health committee terms, that makes the display on my watch a risk factor for the striking of Big Ben. I shouldn’t take that too seriously either if I were you.

Lewis Jones

Lewis Jones is a science writer in the U.K.