In the 1940s, heart disease was the number one killer of Americans. To understand why, the U.S. Public Health Service launched a study to examine the nature and causes of heart disease. They decided to follow the lives and habits of ordinary people living in a Boston suburb called Framingham to determine whether there was any connection between the way they lived and the health of their hearts. Their original goal was to investigate the factors people were born with (genetic factors) and those they were exposed to (environmental factors) and see how each contributed to the development of heart disease.

The study began on September 27, 1948. Healthy adult participants between the ages of 30 and 60 volunteered, and a total of 5,209 men and women agreed to take part in the study. All participants were given a thorough physical examination and answered detailed questions about their family medical history and lifestyle. Every two years, participants were given a physical examination and a variety of tests, including blood tests, electrocardiograms (EKGs) and blood pressure readings.

Later, the most modern heart tests (e.g., echocardiograms) were also added to the protocol to provide the researchers with complete “benchmark” data on each participant. Information was also obtained from hospital admission records, death reports and local physicians. Eventually, the study was taken over by the National Heart Institute, which is now known as the National Heart, Lung and Blood Institute (NHLBI).

In 1971, 5,124 children (and their spouses) of the original study participants were enrolled in the study. This has revealed important data in the 1990s and has been called the Framingham Offspring Study. A third generation (children of the Offspring Study) is currently being recruited for continuation of the study. Researchers are hoping to enroll 3,500 grandchildren of the original group. Like previous participants, these individuals will undergo an extensive cardiovascular assessment.

One major flaw with the original study was the lack of ethnic diversity. The participants are almost entirely white (Caucasian). In the late 1990s, researchers recruited 500 African-Americans, Asian-Americans, Native Americans and other members from Framingham’s growing minority population to participate in the study. This more ethnically diverse study is called “The Omni Study,” and researchers are investigating to determine if minority populations have the same risk factors as those found in other cohort studies.

In addition, the NHLBI has begun a study of cardiovascular disease among African-Americans from the Jackson, MS, metropolitan area. Mississippi’s death rates from cardiovascular disease are among the highest in the nation, particularly among African-Americans. The primary objective of the study is to examine the causes of cardiovascular diseases in African-Americans in order to determine the best strategy to prevent these conditions.

To date, the Framingham study has been an overwhelming success. It has resulted in the publication of over 1,000 scientific papers and earned a respected reputation around the world. Its findings are considered so important that they are routinely taught as part of medical school education and have significantly changed the lifestyles of countless people around the world. The study has lead to the identification of the major risk factors of cardiovascular disease:

• High blood pressure
• High blood cholesterol
• Obesity
• Smoking
• Diabetes
• Reduced physical activity

In addition, the study has provided additional information on other related factors, such as age, gender, socioeconomic elements and psychological issues. A few additional milestones that resulted from Framingham research include:

• In 1960, Framingham researchers linked cigarette smoking to heart disease. In 1981, Framingham researchers debunked the idea that filter cigarettes provide any protection against heart disease among smokers.
  
  
• In 1976, Framingham researchers linked menopause to increased risk of heart disease.
  
  
• In 1978, psychosocial factors were found to affect heart disease.
  
  
• In 1994, an enlarged left ventricle was shown to increased risk of stroke. That same year, Framingham researchers linked lipoprotein (a) to heart disease.
  
  
• In 1996, researchers linked high blood pressure with high pressure by showing disease progression and gradual enlargement of the heart's chambers.

Further information about genetics is hoped to be obtained from the grandchildren and great-grandchildren of the original participants, as Framingham researchers have created a DNA library from more than 5,000 participants across two generations. Advances in diagnostic technology have helped provide even more detailed information with the new participants. As long as it continues to reveal valuable data, the study is expected to continue through future generations.