1960: Cigarette smoking found to increase CHD risk
1961: Cholesterol levels, blood pressure, and electrocardiogram abnormalities found to
increase the risk of heart disease
1967: Physical activity found to reduce the risk of CHD and obesity to increase
the risk of CHD
1977: High HDL cholesterol levels found to protect against CHD
1981: Low LDL cholesterol concentrations linked to low incidence of CHD