Cause and Effect in Epidemiology

Abstract

Thomas Huxley once commented on "the great tragedy of Science — the slaying of a beautiful hypothesis by an ugly fact."¹ In a Special Article by Hulley et al. in this issue, the theory that triglyceride is a cause of coronary heart disease has been wounded gravely, perhaps mortally. The culprit is the ugly fact that in most or all epidemiologic data now at hand, the observed association between triglyceride and coronary heart disease can be entirely explained by other recognized risk factors for the disease. The authors seem to have good epidemiologic reasons for recommending "that widespread screening and . . .