Nicole Hefner
Professor Callahan-Kapoor
Politics of Health
April 3, 2017
Framingham Heart Study
Definition and Background
The Framingham Heart Study, first developed under the National Heart Institute and continuing today under the National Heart, Lung, and Blood Institute, launched a challenging research project in 1948 focused on identifying the general causes of cardiovascular diseases (History of the Framingham Heart Study, 2017). Cardiovascular diseases, or CVDs, such as heart disease, hypertension, and stroke, were very prevalent and deadly during this time period. Framingham is an epidemiological study – it explores relationships in health and disease that cannot be observed directly. The study’s primary goal was to secure epidemiological data on arteriosclerotic and hypertensive cardiovascular diseases; its two secondary goals were to secure data on the prevalence of various forms of CVDs and to test how efficient certain diagnostic procedures in heart disease are. Even before the Framingham study, the medical community had a general consensus that CVDs did not have one singular cause, but that instead they were due to a combination of multiple causes. Prior to the study, some of the hypotheses by researchers were that CVD increases in patients with more advanced age, greater body weight, hypertension, high blood cholesterol levels, and in those who smoke and drink heavily. These hypotheses became the basis of the medical examinations performed on the participants in the study to determine if these factors did indeed cause CVDs (Epidemiological Background and Design, 2017).
The authors of the study recruited a cohort of 5,209 residents of Framingham, Massachusetts between the ages of 30 and 59 to go through physical examinations and lifestyle interviews that would be analyzed for common patterns in the development of CVDs (History of the Framingham Heart Study, 2017). The participants were selected randomly from the town, although when not everyone who was randomly selected opted to participate, the study was forced to accept volunteers as well. Every two years, examinations were done on the cohort to track their overall health, lifestyle changes, and development of CVDs. Prior to the study, high blood pressure was considered normal in the elderly, and minimal effort was made to control patients’ blood pressure because it was not considered unusual. In 1957, after the study had been running for about a decade, Framingham defined hypertension as a blood pressure of 160/95 mmHg or higher, and released their findings that there was a fourfold increase in the incidence of coronary heart disease for study participants with hypertension. Prior to Framingham, doctors were taught that systolic blood pressure, the pressure of blood against artery walls during a heartbeat, was not nearly as important as diastolic blood pressure, the pressure that blood exerts against artery walls between heartbeats; thus, doctors ignored high systolic blood pressure. However, in 1971 Framingham data showed that systolic pressure has an even stronger association with coronary heart disease than does diastolic pressure and is an even better predictor of cerebrovascular accidents and heart failure as well. The Framingham Study changed the long-held belief that systolic pressure was of little consequence (Mahmood et al, 2014).
In an effort to create a more expansive and diverse study, additional cohorts of participants were added over the years. In 1971 Framingham accepted 5,124 of the original participants’ adult children and spouses into the study and called this group the second generation cohort. In 2002, the grandchildren of the original participants became the third generation cohort, and information from each of these related groups was used in concert to identify risks and trends in CVDs (History of the Framingham Heart Study, 2017). Because Framingham is a predominantly white, middle class town, Omni cohorts of ethnic minorities living in Framingham were established in 1994 and again in 2004 to make the study more inclusive of all races and ethnicities (Mahmood et al, 2014).
The Framingham Heart Study succeeded in identifying the major risk factors for CVDs, such as high blood pressure, high blood cholesterol, smoking, obesity, and physical inactivity (History of the Framingham Heart Study, 2017). As Shanthi Mendis describes in his global perspective on the Framingham Heart Study, the Framingham equation that predicts cardiovascular risk is another major contribution of the study. The risk score is calculated “based on age, blood pressure, [and] total or low-density lipoprotein cholesterol level” among other criteria, and provides a “remarkably good ability to discriminate those at risk” for cardiovascular diseases (Mendis 2010, 12). Over the last 50 years, 1,200 articles have been produced and published in medical journals from the Framingham Heart Study. Currently, new technologies such as echocardiography are being integrated into the studies, and research is being expanded to include the role of genetic factors in CVDs (History of the Framingham Heart Study, 2017). The Framingham Heart Study has been a milestone in medical research studies and will undoubtedly continue to make monumental contributions to the scientific community in upcoming years.
Controversy/Perspectives
The two main controversies surrounding the Framingham Heart Study concerned the randomness of the cohorts chosen to participate in the study and the diversity of the pool that participants were chosen from. Framingham was chosen as the site for the heart study because the town has many characteristics that make it suitable for a long-term epidemiological study. The town was large enough to provide enough participants for the study yet compact enough that the whole study population could be easily observed. Other factors that made Framingham a suitable town to base the study were that the population was stable and allowed regular follow-up visits of the participants, and that medical professionals in the area were supportive of the study, fostering a spirit of cooperation. However, Framingham investigators were aware that the town was not a true representation of the diversity of the United States’ population. Ideally, the study would have been set up in a way that many different ethnic groups could have been represented and in such a manner that geographic, socioeconomic, and environmental factors could be taken into account as well. Framingham, however, was a white, middle-class town, and there have been critiques of the study claiming that its lack of diversity lessens the validity of its findings (Epidemiological Background and Design, 2017). Nevertheless, Framingham was one of the first cohort studies to recruit women, which provided it with some diversity in its representation that many other studies of the time did not have (Mendis, 2010). Additionally, Framingham has made efforts in recent years to diversify by recruiting cohorts of ethnic minorities called Omni cohorts (Epidemiological Background and Design, 2017).
The other main controversy surrounding the Framingham Heart Study is the randomness of the participants. The original plan for the study was to have 6,000 individuals between the ages of 30 and 59 participate in the study out of the 10,000 individuals in Framingham that fit this criteria. Lists were created for each precinct in the town, and two out of every three families in each precinct were selected and invited to participate in the study. The initial sample size was 6,507 subjects, but only 4,469 of those individuals showed up for an initial examination, making the initial response both poor and biased. A response rate less than 70% is not ideal – this rate was only 68.7% – and those who did respond were healthier than the nonrespondents. In order to get participant numbers exceeding 5,000, 888 volunteers were invited for an examination, and from these, 740 were added to the cohort. Investigators expected to find one in six of the participants to have a CVD but instead found only one in fifty; the cohort was healthier than the general population, which led to this unexpected finding. This discrepancy precluded the Framingham Heart Study from yielding reliable information on the prevalence rates of certain types of CVDs because the numbers from the healthier population would have been underestimates of actual prevalence rates. Nevertheless, the study was still capable of providing estimates on incidence rates – the rates of individuals developing a condition over a certain time frame. The Framingham Heart Study demonstrated the relationship between risk factors and the development and progression of cardiovascular diseases, despite not being able to conduct the study with a perfectly random participant pool (Epidemiological Background and Design, 2017).
Historical/Topical Context
Before the Framingham Heart Study, very little was known about the prevention and treatment of cardiovascular diseases, and early death was accepted as unavoidable for many individuals (Mahmood et al, 2014). Prior to World War II, public health focused on controlling infectious diseases. Efforts from the 1930s to 1950s succeeded in improving sanitation, and the creation of penicillin in 1942 helped to reduce rates of tuberculosis and pneumonia. Throughout the 1940s and 1950s, the United States saw increasing numbers of patients with cardiovascular disease. Heart disease became the number one killer in the country, and there was no known treatment for it at the time (Epidemiological Background and Design, 2017). President Roosevelt’s death in 1945 from cerebral hemorrhage, a byproduct of extreme hypertension, stirred up sentiments to learn more about the causes of cardiovascular diseases, and in 1948, President Truman signed the National Heart Act. This act provided a $500,000 grant for the establishment of the National Heart Institute and began a 20-year-long epidemiological study of heart disease (Mahmood et al., 2014)
At the time, basic research was not revealing helpful information about CVDs, and because these conditions are typically degenerative diseases, some hypothesized that a preventive approach could delay the onset of the diseases. But first, predisposing factors needed to be identified. The Framingham Heart Study was designed as an epidemiological study, the first of its kind, to determine the underlying causes of cardiovascular diseases. While previous epidemiological studies focused on single causes of epidemics, Framingham considered several hypotheses regarding the causes of cardiovascular diseases (Epidemiological Background and Design, 2017). During this period, the term “risk factor” was popularized, and Framingham contributed to a shifting focus from concentration on treatment of illnesses to prevention of illnesses (Mahmood et al., 2014).
In 1969, the National Institute of Health attempted to phase out the Framingham Heart Study, forcing investigators to raise private funds. However, President Nixon intervened, allowing the study to continue, and in 1971, the leaders of the Framingham study created a pact of monetary support with Boston University so that they would no longer need private donors (Mahmood et al., 2014). The Framingham Heart Study still works today to make groundbreaking medical advances and contribute to the scientific community (History of the Framingham Heart Study, 2017).
How it relates to politics of health
The Framingham Heart Study, with its recruitment of civilians from Framingham, Massachusetts, relates to the politics of health through the concept of ready-to-consent versus ready-to-recruit populations. There is a difference between individuals who are recruited to participate in a study and individuals who provide their free and informed consent to participate. Some medical studies present themselves in a way that almost forces certain individuals to participate because they have no other viable access to treatment; this group of people comprises ready-to-recruit populations. Other groups of individuals who have the means to better alternatives for treatment than participation in clinical trials make up ready-to-consent populations. In the Tuskegee Syphilis Study, patients with syphilis were not treated with penicillin in order for doctors to observe the progression of the disease. These patients were not given full information about their condition nor were they made aware that effective treatment for their condition existed. However, the participants were generally poor and uneducated, and if they were not part of the study, they still would not have been receiving treatment for syphilis. This group of patients is a classic example of a ready-to-recruit population who has nothing to lose from participating in a study (Fisher, 2015). In the Framingham Heart Study, it is not made clear how much information the participants were given ahead of time. From the literature, it seems that the authors of the study expected the families chosen at random to participate in the study because they were surprised when only 68.7% of the subjects responded and additional volunteers had to be sought out. The Framingham Heart Study website did not give specific information on the steps the investigators took to obtain the consent of the participants. Although the Framingham Heart Study was an observational study to find out the causes of cardiovascular diseases, it is still important, ethically and by law, to fully inform participants of their role in the study and about what any discoveries made through the study will be used for. Today, there are informed consent laws that regulate such issues. Whether the participants in the Framingham Heart Study were fully informed and could be considered a ready-to-consent population is unclear; although most participants were recruited from the general population of Framingham, there was no previous consensus given by everyone in the town that they knew the facts about the study and gave their approval to participate.
Bibliography
“Epidemiological Background and Design: The Framingham Study.” Framingham Heart Study. 2017. Accessed April 3, 2017. https://www.framinghamheartstudy.org/about-fhs/background.php
Fischer, Jill A. “‘Ready-to-Recruit’ or ‘Ready-to-Consent’ Populations? Informed Consent and the Limits of Subject Autonomy.” Qualitative Inquiry 13, no.6 (2007): 875-94.
“History of the Framingham Heart Study.” Framingham Heart Study. 2017. Accessed April 3, 2017. http://www.framinghamheartstudy.org/about-fhs/history.php
Mahmood, Syed S., Daniel Levy, Ramachandran S. Vasan, and Thomas J. Wang. “The Framingham Heart Study and the epidemiology of cardiovascular disease: a historical perspective.” The Lancet 383, no. 9921 (2014): 999-1008.
Mendis, Shanthi. “The Contribution of the Framingham Heart Study to the Prevention of Cardiovascular Disease: A Global Perspective.” Progress in Cardiovascular Diseases 53, no. 1 (2010): 10-14.
« Back to Glossary Index