Despite the substantial scientific interest and the obvious public health implications of the diet and heart disease issue, relatively few observational cohort or case-control investigations had been published prior to 1985. Although these observational studies were not entirely consistent, taken collectively, they tended to provide important general support for the diet-heart hypothesis. However, due to study design, limited numbers of endpoints, or methods of analysis, many central questions remained unanswered. The most important issue was the quantitative relationship between specific dietary factors and risk of coronary heart disease.