WHEN DID PEOPLE FIRST BEGIN TO STUDY ENVIRONMENTAL EFFECTS?
One of the first large studies to investigate complex diseases was the Framingham study. This project began in 1948 and initially studied a variety of factors for increased risk of stroke and heart disease in approximately 5,000 individuals. By studying many thousands of people for an extended period of time (several decades), this study identified a variety of factors important for people’s health. Smoking, obesity, high blood pressure, high cholesterol levels, and other factors were found to be linked to heart disease. These observations led to important recommendations that are still used by physicians for their patients. Later, analysis of DNA from this group and many other large-scale studies identified many genetic regions associated with heart disease, obesity, and diabetes.