MRFIT results published.
One of these was the Multiple Risk Factor Intervention Trial, known as MRFIT (pronounced Mr. Fit), which ran from 1973 to 1982. Stamler had the prestigious job of directing it. After his lackluster efforts to get people to adhere to the ersatz foods he had invented for the National Diet Heart Study, Stamler thought that perhaps a better intervention would be to focus less on diet and more on controlling other factors, such as smoking, weight loss, and blood pressure. MRFIT therefore used the “everything but the kitchen sink” approach to fighting heart disease. It was one of the biggest and most demanding medical experiments ever performed on a group of human beings, involving twenty-eight medical centers
used margarine instead of butter, limited eggs to two or fewer per week, and avoided meat and desserts; the target for saturated fat was 8 percent to 10 percent of calories. The other half were told to eat and live however they liked. Stamler followed all twelve thousand men for seven years.XIII
The results, announced in September 1982, were a disaster for the diet-heart hypothesis. Although men in the intervention group had been spectacularly successful in changing their diets, quitting smoking, and reducing their blood pressure, they died at slightly higher rates than the controls. The MRFIT investigators acknowledged this and floated various possible explanations. One was that the control group had also, independently, reduced rates of smoking and sought medication to control blood pressure, so by the end of the study the differences between the two groups were not as great as expected. Another possible explanation was that the diuretics used to treat high blood pressure were toxic (this idea was disproved). A final idea was that perhaps people would need to start such interventions earlier in life or keep them up over a longer period of time to see results.
nationwide at a cost of $115 million.
Stamler’s teams measured the cholesterol of 361,000 middle-aged American men and found twelve thousand whose cholesterol was above 290 mg/dL—so high that they were considered to be at imminent risk of heart attack.XII Most of the twelve thousand were obese, had high blood pressure, and smoked, so they had plenty of risks to modify. Half of them then received “multiple” interventions: counseling to quit smoking, medication to lower high blood pressure, if necessary, and advice on how to follow a low-fat, low-cholesterol diet. They drank skim milk,