FRAMINGHAM HEART STUDY
Almost daily, we are warned that certain behaviors, certain lifestyle choices, may be dangerous to our cardiovascular health. Many of these assertions are based on sound medical logic and years of careful observation. How do we know what we know? The following was provided by the National Heart, Lung, and Blood Institute (NHLBI), part of the U.S. National Institutes of Health.
Fifty years have passed since medical researchers began tracking the course of cardiovascular disease in a small New England town. Much of what is known today about risk factors for cardiovascular disease: cigarette smoking, high blood pressure, high blood cholesterol, overweight, physical inactivity, and diabeteswas a mystery before this project, the "Framingham Heart Study."
In 1948, more than 5,000 residents of Framingham, MA, agreed to participate in a long-term ongoing study of heart disease, to be administered by the newly established National Heart Institute (today the NHLBI) of the National Institutes of Health.
At the time the study was conceived, it was already known that cardiovascular disease was the leading cause of death and serious illness in the United States. But researchers wanted to track a large population, to see how heart disease develops. The original participants, who were between 30 and 60 years of age at the time they enrolled in the study, underwent detailed physical examinations every two years, including an electrocardiogram, chest X ray, and laboratory tests.
The Framingham Heart Study is now considered one of the longest, most important epidemiological studies in medical history. In the 1960s, the study demonstrated the role cigarette smoking plays in the development of heart disease. Those findings helped to fuel the first anti-smoking campaigns of that era.
Data gathered from the participants also showed how elevated blood pressure contributes to the risk of heart attack and stroke. In 1972, the NHLBI established the National High Blood Pressure Education Program. Over the last 25 years, the program's efforts have helped to increase public awareness about the risks of high blood pressure, promote better control of blood pressure, and reduce deaths from strokes.
The Framingham study provided researchers with knowledge of how dietary fat can increase the risk of heart disease. It showed a link between cholesterol levels in the blood and an individual's risk for developing heart disease. Later, Framingham data also demonstrated the beneficial role of high-density lipoprotein (HDL) cholesterol and the negative consequences of low-density lipoprotein (LDL) cholesterol. The National Cholesterol Education Program was established in 1985 by the NHLBI after studies, including Framingham, proved that a lower blood cholesterol level meant a lower risk of heart disease. This program has helped to educate physicians, patients, and the public about the dangers of high blood cholesterol and to bring about reductions in Americans' blood cholesterol levels.
Today, about 75 percent of the original Framingham participants have died. The most common cause of death was cardiovascular disease. But in 1971, the study began a second phase by enrolling more than 5,000 children of the original participants along with their spouses. This second generation is providing researchers with valuable information about the genetic patterns of heart disease.
Framingham will continue to evolve as new technologies emerge to monitor the heart and the progression of cardiovascular disease. To stay on the cutting edge of medical science, the study has implemented new technologies over the years as they became available.
The study also is collaborating with researchers around the world to gather information about other topics, including osteoporosis, nutrition, and eye and lung diseases.
Several new Framingham initiatives are under way, including research into the genes responsible for heart disease, high blood pressure, lung disease, and osteoporosis. Enrollment of minority participants is helping the researchers gather important data on risk factors in minority populations.
The commitment of the residents of Framingham, MA, has been crucial in the study's efforts. Their help has contributed to many of the major findings about heart disease made in the last half-century. Their continued participation is a crucial element for future success in the battle against the nation's number-one killercardiovascular disease.
BLOOD CHOLESTEROL LEVELS
Desirable Borderline High
Total < 200mg/dL 200-239mg/dL 240mg/dL & up
LDL < 130mg/dL 130-159mg/dL 160mg/dL & up
HDL a low HDL cholesterol is less than 35mg/dL
BLOOD PRESSURE LEVELS
Optimal <120 mm Hg and <80 mm Hg
Normal <130 mm Hg and <85 mm Hg
High-Normal 130-139 mm Hg or <85-89 mm Hg
Stage 1 140-159 mm Hg or 90-99 mm Hg
Stage 2 160-179 mm Hg or 100-109 mm Hg
Stage 3 >=3D 180 mm Hg or >=3D 110 mm Hg