January 1, 1991
Framingham publishes new findings and the predictive power of total cholesterol was not nearly as strong as study leaders had originally thought.
However, thirty years later, in the Framingham follow-up study—when investigators had more data because a greater number of people had died—it turned out that the predictive power of total cholesterol was not nearly as strong as study leaders had originally thought. For men and women with cholesterol between 205 and 264 milligrams per deciliter (mg/dL), no relationship between these numbers and heart disease risk could be found. In fact, half of the people who had heart attacks had cholesterol levels below the “normal” level of 220 mg/dL. And for men aged forty-eight to fifty-seven, those with cholesterol in the midrange (183–222 mg/dL) had a greater risk of heart attack death than those with higher cholesterol (222–261 mg/dL). Total cholesterol turned out not to be a reliable predictor for heart disease after all.
Because the Framingham leaders had been trumpeting total cholesterol as the best possible risk factor for heart disease for so many years, they did not take great pains to publicize these weaker follow-up numbers when they came out in the late 1980s. (Soon they would be shifting the conversation over to cholesterol subfractions, known as high-density lipoprotein [HDL] and low-density lipoprotein [LDL], which could now be measured and whose predictive powers showed more promise, although even aspects of these subfractions turned out to be disappointing in the end, as we’ll see in Chapters 6 and 10.)
The Framingham data also failed to show that lowering one’s cholesterol over time was even remotely helpful. In the thirty-year follow-up report, the authors state, “For each 1% mg/dL drop of cholesterol there was an 11% increase in coronary and total mortality [italics added].” This is a shocking finding, the very opposite of the official line on cholesterol lowering. Yet this particular Framingham finding is never discussed in scientific reviews, even though many large trials have found similar results.
Other important findings from Framingham have also been ignored, including—notably—those on dietary risk factors, which were examined in the part of the study that Mann conducted. Together with a dietician, Mann spent two years collecting food-consumption data from one thousand subjects, and when he calculated the results in 1960, it was very clear that saturated fat was not related to heart disease. Concerning the incidence of coronary heart disease and diet, the authors concluded, simply, “No relationship found.”