In this culture of the quantified self one is awash with an endless stream of numbers: blood pressure, daily steps taken, pulse, hours slept, calories consumed, body mass index, percent body fat, blood sugar... We have endowed these figures and their white-coated accountants with the power of an infallible fortuneteller.
The king of this calculus is cholesterol, public enemy number one.
If there's one number the health-conscious know, it's their cholesterol level. We've been told that cholesterol comes in two flavors: "good" cholesterol (high density lipoprotein/HDL) and "bad" cholesterol (low density lipoprotein/LDL). We've also been convinced that high LDL levels predict heart disease and lowering them will protect you. One in four Americans age 45 or older (about 32 million) take medication daily to buy that protection.
How did cholesterol rise to the top of the cardiac killers roster and so successfully dominate the hearts and minds of the public?
The cholesterol story began to coalesce with Ancel Keys' landmark seven countries study in 1970. He suggested a causal link between diets high in dietary saturated fat, blood cholesterol levels and heart disease. A national experiment in dietary fat reduction ensued. Unfortunately, you don't need a statistician to see that this experiment failed to prevent the epidemic of obesity and diabetes that causes most contemporary heart disease. In fact, it may have facilitated it.
Most theories about what's good for you do not age well, and evidence for this fat hypothesis has thinned. One particularly disruptive phenomenon is the large population who has a heart attack in the absence of elevated LDL levels. A large national study found approximately 50 percent of patients hospitalized for heart attack had LDL levels classified as optimal (<100mg/dL).
Statins (Lipitor, Mevacor, Crestor, Zocor), the treatment of choice for lowering cholesterol, also complicated an understanding of the role cholesterol plays in heart disease. Because statins do decrease both cholesterol levels and the risk for cardiovascular disease, it was assumed that this was the whole story. However we have learned that statin's therapeutic effects are largely achieved through a remarkably wide range of actions including the ability to decrease inflammation, improve the health of arterial walls, decrease excessive clotting and stabilize atherosclerotic plaque so it doesn't flake off and cause a heart attack or stroke.
Studies have demonstrated that statin-treated subjects have significantly lower risk for cardiovascular disease compared to age-matched subjects on placebo, despite comparable cholesterol levels. No association between cardiac event rate and the level of LDL reduction has been shown. Because the risk reduction conferred by statins appears independent of pretreatment cholesterol levels, some suggest their use regardless of cholesterol readings.
So the use of cholesterol testing, something that fuels fears of fatal disease and billions of dollars in drug sales, has significant flaws.
The other irony of this cholesterol story is the dietary advice it has generated. As mentioned earlier, a supposedly causal link between diets high in dietary saturated fat, blood cholesterol levels and heart disease launched the era of low-fat diets.
A significant body of evidence suggests that this reduction in dietary saturated fat (and its replacement with carbohydrate) kindled today's inferno of metabolic disease, obesity and diabetes.
Last week, in the latest chapter of confusing cholesterol interpretation, new guidelines were released for cardiovascular disease risk assessment. The new approach is both good and bad news.
The good news is that cholesterol numbers are no longer the central focus. The bad news is that the new math of risk calculation could paradoxically push millions of people onto statins who would gain no health benefit but would risk harmful side effects.
One might feel encouraged by the devaluation of cholesterol and the inclusion of several other variables (age, gender, smoking, systolic blood pressure and whether taking blood pressure medication) in the new estimation of cardiovascular disease risk. But sadly, the basic premise remains the same. Risk assessment is the equivalent of deciding who needs medication.
Lip service is given to the importance of lifestyle variables such as diet, weight, stress, sleep and exercise. But the funding for lifestyle research, education (for both physicians and the public), and behavior modification, remains a tiny fraction of the budget for drug therapy.
Moving the medical-industrial complex from sick care to health care is like an aircraft carrier making a U-turn. Slow.
Full speed ahead.