Diet and coronary heart disease: the statistical analysis of risk.

DESPITE reports of more than a dozen authoritative bodies over the past 10 years, the relationship between diet and coronary heart disease (CHD) remains controversial. Comparisons of different populations have indicated a correlation between the consumption of saturated fat and plasma cholesterol levels, and similar studies have established the role of elevated plasma cholesterol as a risk factor for CHD. Within a given population, however, the correlation between dietary saturated fat and plasma cholesterol has not been established outside the controlled conditions of a metabolic ward. In Western societies, it is commonly recommended that consumption of saturated fat be reduced, but whether such a reduction in plasma cholesterol levels would result in a decrease in the incidence of CHD has not been established. In the World Health Organization's trial with clofibrate,' the therapeutically induced reduction in cholesterol reduced nonfatal myocardial infarctions,2 but the overall mortality in the treated group after 4 years was 25% greater than that in the control groups.3 A recent report by the National Research Council of the National Academy of Sciences has heightened the argument concerning the value of dietary change in the general population by recommending that the "normal, healthy" American need not be concerned with dietary intake of fat or cholesterol.4 Gordon et al.5 offered further evidence on the matter of diet and CHD through a study of three populations. They found that consumption of alcohol, starch and total calories in the diet each had an inverse relationship with CHD. These findings do not contradict the view that reduction of dietary saturated fat may decrease CHD in Western society. The substitution of starch for fat is illustrated in the Puerto Rico and Honolulu studies. The negative relationship between CHD and total caloric intake is consistent with beneficial effects of physical activity. The inverse relationship between CHD and alcohol consumption deserves some comment. Alcohol consumption is known to raise the level of HDL cholesterol. However, alcohol intake has several negative aspects, including the higher overall mortality in the present study, the relationship with cirrhosis of the liver, the