Today, one of the leading causes of mortality in the US is cardiovascular diseases (CVD). It is considered to be one of the serious illnesses; there are one out of four deaths every year from CVD in the US (Go, 2013). To understand the common factors that contribute to development of CVD, a study termed as the “Framingham Heart Study” was initiated way back in 1948 (FHS, 2013). At this time, there was very little knowledge on the general causes of heart disease, but there was a rising incidence of CVD in the US and it had almost become an epidemic. At such crucial times, the Framingham study was initiated under the direction of the National Heart Institute, which is recognized as the National Heart, Lung, and Blood Institute (NHLBI). The study design is observational and cohort type. It is still ongoing (FHS, 2013).
The Framingham Heart Study initially recruited 5209 participants of both the genders between the age group of 30 and 62 years. Patients recruited were those who had not yet developed sypmtoms of CVD, or suffered a stroke or heart attack (FHS, 2013). While recruitment, they were enquired for their general health, medical history, family history, and medications (including cholesterol and hypertension medications, aspirin, diuretics, and any other over-the-counter and prescription drugs). Physical examinations and lifestyle patterns were assessed, which the investigators later used to analyze for patterns of CVD development. Since 1948, participants are assessed every two years and are made to undergo a detailed medical history, physical examination, and laboratory tests (FHS, 2013).
New cohorts have been added multiple times to the study – offspring cohort (1971), Omni cohort (1994), third generation cohort (2002), new offspring spouse cohort (2003), and second generation omni cohort (2003). The 1971 cohort enrolled the second-generation group -- 5,124 men and women who are adult children of the participants of the original study started in 1948. Their spouses were also included. The third generation cohort recruited 4095 grandchildren of participants of the original study; the first phase of this cohort was completed in 2005 (FHS, 2013).
Over past 65 years, the study has been identifying and providing insights into major CVD risk factors such as hypertension, smoking, lack of physical activity, age, blood cholesterol and triglyceride levels, obesity, gender, and psychosocial issues. The study is also investigating other risk factors such as dementia, certain physical traits, and genetic patterns (FHS, 2013).
The earliest analysis of the study was published in 1960, exactly 12 years after its initiation, which stated smoking to increase the risk of heart disease. Findings published a year later in 1961 stated blood pressure (hypertension), cholesterol level, and ECG abnormalities to increase the risk of coronary heart disease (CHD). According to findings published in 1967, lack of physical activity and obesity were shown to lead to development of CVD in an adult. In the period between 1970 to 1978, very important results were published that showed hypertension, atrial fibrillation, psychosocial factors and menopause (in women), to increase the risk of CVD and stroke. According to outcomes published in 1999, lifetime risk for developing CVD at the age of 40 is one in two for men and one in three for women. In results published in 2002, the risk factor for heart failure was identified to be obesity. Social networking has an important role to play in a person’s decision to quit smoking, was also shown by the study. In 2009, the study reported a new genetic variant associated with increased vulnerability for atrial fibrillation (AF). It was also instrumental in showing parental dementia’s association with poor memory of their offspring’s in adulthood; and that high leptin levels may offer protection against dementia. In 2010, the study outcomes published showed sleep apnea tied to increased risk of stroke, additional genes to play a role in Alzheimer’s disease, and abdominal obesity to be associated with smaller brains in old age. It also found genes linking puberty timing and body fat in women (FHS Research Milestones, 2013).
Impact of Framingham Heart Study
The study is continuing to provide significant insights in the area of cardiovascular segment for past 60 years. It has influenced significant investigations across the globe. Public health initiatives are underway to demonstrate sedentary lifestyle modifications to improve cardiovascular outcomes (Greenberg, 2010). Nationwide cardiovascular disease prevention programs are conducted. When risk factors for CVD like obesity, smoking, tobacco use, physical inactivity, hypertension, hypercholesterolemia, and diabetes were first published, these were novel CVD risk factors, now these risk factors are the major focus of national and international prevention programs. The insights provided by the study have changed the healthcare profession’s approach towards CVD and has launched a new field of preventive medicine (Greenberg, 2010).
The study is particularly important for women because it is the first major cardiovascular study to include women. Traditionally, it was thought that CHD is the disease predominantly affecting the men; therefore women were not included in most of the studies of the past. The Framingham study showed that while CVD occurred twice as often in men, the incidence of CVD in women approaches that seen in men with advancing age (Brink, 1998). Coronary attacks were more fatal in women than in men; menopause was seen to be associated with significant rise in coronary events. As an impact of the study, in 1994, only 23% of women were reported to smoke. Since Framingham linked menopause to increased risk of CHD, gynecologists routinely recommend hormone replacement therapy (HRT) for their menopausal patients (Brink, 1998).
Thus, Framingham Heart Study is considered to be one of the most renowned works in the history of medicine that has made a significant impact not only on the health of men, but also women; and made them change the way they lead their lives.
Go AS, Mozaffarian D, Roger VL, Benjamin EJ, Berry JD, Borden WB, et al. Heart disease and stroke statistics—2013 update: a report from the American Heart Association. Circulation. 2013;127(1):e6-e245.
About the Framingham Heart Study. (2013) Framingham Heart Study. Retrieved from: http://www.framinghamheartstudy.org/about; Accessed: 20 April 2013.
Research milestones. (2013) Framingham Heart Study. Retrieved from: http://www.framinghamheartstudy.org/about/milestones.html; Accessed: 20 April 2013.
Henry Greenberg. (2010). Progress in Cardiovascular Diseases. The Framingham Heart Study – Global Impact, Ongoing Influence. Retrieved from: http://www.elsevier.com/about/press-releases/research-and-journals/the-framingham-heart-study-global-impact,-ongoing-influence
Brink, S., (1998) Unlocking the heart's secrets. US news. Retrieved from: http://www.forces.org/articles/files/fram.htm; Accessed: 20th April, 2013.