Myths In Medicine
While remembering that it’s a myth that myths are myths, we’re into questioning some of the received wisdom being passed down from our forefathers. One of the more commonly known “facts” out and about these days is that high cholesterol causes heart disease. Rand Simberg questions the answers.
One of the prevailing myths of modern life (I use the word here in the sense of something that everyone believes, not necessarily something that is false) is that cholesterol causes heart disease and stroke, and that reducing it will reduce the risk of heart disease and stroke. But the recent Vytorin issue should give us cause to question this conventional wisdom.Whenever I’ve looked at the research, I’ve never been able to see any clear indication that taking cholesterol-reducing medication actually reduces risk, per se–all that the clinical studies that I’ve seen seem to indicate is that cholesterol reduction is taking place. But correlation is not causation. It could be that both high cholesterol and vascular disease are caused by some third factor that hasn’t been identified, and that in reducing cholesterol, whether by diet or medication, or both, we are treating a symptom rather than a cause.
And the Vytorin issue? From the linked NYT article:
Vytorin is a combination of cholesterol-lowering drugs, one called Zetia and the other a statin called Zocor. Because the two drugs lower LDL cholesterol by different mechanisms, the makers of Vytorin (Merck and Schering-Plough) assumed that their double-barreled therapy would lower it more than either drug alone, which it did, and so do a better job of slowing the accumulation of fatty plaques in the arteries which it did not.Heart disease specialists who were asked to comment on this turn of events insisted that the result implied nothing about their assumption that LDL cholesterol is dangerous, only about whether it is always medically effective to lower it.
But this interpretation is based on a longstanding conceptual error embedded in the very language we use to discuss heart disease. It confuses the cholesterol carried in the bloodstream with the particles, known as lipoproteins, that shuttle that cholesterol around. There is little doubt that certain of these lipoproteins pose dangers, but whether cholesterol itself is a critical factor is a question that the Vytorin trial has most definitely raised. It’s a question that needs to be acknowledged and addressed if we’re going to make any more headway in preventing heart disease.
So just how long has this – um – situation – been going on?
The truth is, we’ve always had reason to question the idea that cholesterol is an agent of disease. Indeed, what the Framingham researchers meant in 1977 when they described LDL cholesterol as a “marginal risk factor” is that a large proportion of people who suffer heart attacks have relatively low LDL cholesterol.
So daily I’m taking an expensive drug (expensive even with most of the costs taken out by my insurance, which means I pay for it with money taken out of every paycheck before it’s even printed…) that may not be doing anything for me except changing a meaningless number on a test. Maybe. Or not.
It has one other effect. It makes me raise an eyebrow.
[Pokes finger in the air and does a Horshack.] Ooh! Ooh! I have a question. Can the FDA say Scientific Method???