Figure 1. The Cholesterol Hypothesis. Between the years 1955 and 1985, many epidemiologic studies showed a positive relation between cholesterol levels and atherosclerotic cardiovascular disease (ASCVD) events. Over the next 30 years, a host of randomized controlled clinical trials has demonstrated that lowering cholesterol levels will reduce risk for ASCVD. This bidirectional relationship between cholesterol levels and ASCVD provides ample support for the cholesterol hypothesis.