Friday, February 11, 2011

The Framingham Heart Study

The Framingham Heart Study is one of the oldest and most widely cited research studies in the history of medicine. Russ Hobbie and I mention the study briefly In Section 2.4 of the 4th edition of Intermediate Physics for Medicine and Biology, when discussing exponential decay.
“Figure 2.8 shows the survival of patients with congestive heart failure for a period of nine years. The data are taken from the Framingham study [McKee et al. (1971)]; the death rate is constant during this period.”
The data in Fig. 2.8 is from a paper with over 1400 citations in the scientific and medical literature: P. A. McKee, W. P. Castelli, P. M. McNamara, and W. B. Kannel (1971). The natural history of congestive heart failure: The Framingham study. New Engl. J. Med. 285:1441-1446. The abstract to the paper states
“The natural history of congestive heart failure was studied over a 16-year period in 5192 persons initially free of the disease. Over this period, overt evidence of congestive heart failure developed in 142 persons. In almost every five-year age group, from 30 to 62 years, the incidence rate was greater for men than for women. Although the usual etiologic precursors were found, the dominant one was clearly hypertension, which preceded failure in 75 per cent of the cases. Coronary heart disease was noted at an earlier examination in 39 per cent, but in 29 per cent of the cases it was accompanied by hypertension. Precursive rheumatic heart disease, noted in 21 per cent of cases of congestive heart failure, was accompanied by hypertension in 11 per cent. Despite modern management, congestive heart failure proved to be extremely lethal. The probability of dying within five years from onset of congestive heart failure was 62 per cent for men and 42 per cent for women.”
In 2005, Daniel Levy and Susan Brink published A Change of Heart: How the Framingham Heart Study Helped Unravel the Mysteries of Cardiovascular Disease. The book is a fascinating history of this landmark study. Levy (the study’s current director) and Brink (formerly a writer for U.S. News & World Report) write
“A turning point in our evolving understanding of heart disease was the establishment of the Framingham Heart Study in 1948. It was a large and ambitious community-based research project unlike anything that had been conducted before. It came at a time of growing awareness that cardiovascular disease was sweeping the country, even slowing down what should have been a steady rise in life expectancy. It was also a time, three years after the end of World War II, when resources from the national treasury, no longer needed for military purposes, could be used for research into the nation’s leading killer….

In light of this ignorance [of how to treat coronary disease], the U.S. government in 1948 made a twenty-year commitment to uncovering the root causes of heart disease. That scientific resolve was sponsored by the U.S. Public Health Service with half a million dollars of start-up funding from Congress. A cadre of physicians, scientists, government officials, and academics—many of whom knew each other from having served together at military hospitals during the war—selected a New England town in which to carry out this national scientific experiment. The Framingham Heart Study turned out to be instrumental in changing the attitudes, if not the behavior, of virtually every American, and it put the otherwise ordinary town of Farmingham, Massachusetts, on the map….

They [the Heart Study researchers] needed the 5209 men and women from Framingham at first, followed by 5124 of their sons and daughters, and now 3500 of their grandchildren who have donated their medical histories to science. It is ironic, perhaps, that this most respected—even beloved—piece of epidemiology centers on the heart, the organ that symbolically aches, breaks, longs, and loves like no other. It took a commitment from thousands of volunteers to make the study a success.”
I found Chapter 5, “The People Who Changed America’s Heart: Voices from Framingham,” to be particularly inspiring. For instance, they quote Evelyn Langley—housewife, mother, and PTA president—who played an early role in promoting the study among potential participants, and was a participant herself.
“Langley’s heart still lies with the Study. ‘When they call me up and tell me it’s time to come in for an exam, I know I have that ritual to do,’ she says. She has made the trip to the clinic twenty-seven times so far. ‘I am trying to give back to the Heart Clinic [Study] what they have given me. I always feel as if I am part of something bigger than myself. It’s not just for the people who live in this town. Many lives have been saved because of the Heart Study.' ”
You can learn more about the Framingham Heart Study at the study’s website: http://www.framinghamheartstudy.org. Also, you can view a video about it from CBS’s Sunday Morning with Charles Osgood. The study is currently funded by the National Heart, Lung, and Blood Institute (part of the National Institutes of Health) and Boston University. Let me finish with a fitting quote from the acknowledgments of A Change in Heart:
“This book would not have been possible without the more than fifty years of dedication and commitment from three generations of Framingham Heart Study volunteers. We would like to thank them all for providing a gift to the world that has changed untold millions of lives.”

1 comment:

  1. "...The probability of dying within five years from onset of congestive heart failure was 62 per cent for men and 42 per cent for women."

    What is the probability of dying within five years from the onset of congestive heart failure today?

    ReplyDelete