As the longest standing heart
health study in the world, Framingham
Heart Study, at Framingham,
Massachusetts, continues to mine
vast data for the last sixty years regarding the cause of heart trouble and
heart study was conceived by Joseph Mountin, an Assistant Surgeon General and
head of the Division of Chronic Diseases in the US Public Health Service. . The
goal of the study is to learn and establish how cardiovascular disease begins,
evolves and ends fatally.
Research statistics indicate that heart disease is the number one cause of death and serious illness in the US. In fact
approximately 2,400 Americans seem to die of cardiovascular disease daily
according to the American Heart Association. An estimated 80 million in the US suffer a
cardiovascular condition. And Framingham
heart study has played a major role in identifying key risk factors for
Framingham heart study
This refers to a longitudinal epidemiological study
of cardiovascular factors undertaken on the initial population of 5,209 men and
women in the age group of 30 to 60 who were healthy, based in Framingham Massachusetts.
This study is a joint project of the National Heart Institute, Lung and Blood
Institute and Boston
Until this time, very little was
known about the causes of heart disease and stroke. Death rate for CVD has been
steadily increasing in the US
and has indeed become an American epidemic.
The first round of extensive physical examinations and lifestyle studies was conducted on 5,209 men and
women who were healthy and ranging in ages 30 to 62 in the 1948. Since then,
every two years, detailed medical history, physical examinations and diagnostic
tests are carried out on the identified men and women folks. Participants in
the study has been tracked using standardized biennial cardiovascular
examination, daily surveillance of hospital admissions, information pertaining
to death and information obtained from the physicians and sources outside the
In 1971, a second generation of 5,124 original participants' adult children and spouses were enrolled for
similar examinations. Again in year 2002, enrollment of third generation
participants, the grandchildren of the original cohort had begun. This is
considered as a vital step to increase the understanding of heart disease and
stroke and how these affect families. This third generation study was completed
in July 2005 and it involved 4,095 participants.
Recently, the study has integrated new diagnostic technologies such as echocardiography, carotid artery
ultrasound, magnetic resonance imaging of heart and brain, CT scans of the
heart and bone densitometry into the past and ongoing protocols.
Major CVD risk factors identified in Framingham study
Framingham heart study, after decades of
careful monitoring of the population has led to identification of major CVD
risk factors namely:
- High blood pressure
- Physical inactivity
- Factors such as blood triglycerides, HDL cholesterol levels, age and gender
Framingham heart study risk score
The study estimates the risk of
various cardiovascular disease outcomes in different time horizons. These are
available as score sheets and direct risk functions. The risk prediction
algorithm takes the following components into account:
- cardiovascular outcome
- population of interest
- time horizon
- risk factors
According to the risk score
calculation, the subjects receive a point score based on certain categorical
- Total cholesterol
- High density lipoprotein
- Blood pressure
- Cigarette smoking
- Diabetes mellitus
- Left ventricular hypertrophy
These factors have been analyzed
in the Framingham Heart Study for creation of a model for Coronary heart
disease CHD prediction. The score sheet can be accessed online. Several multivariate
models for estimation of 10-year absolute risk of developing coronary heart
disease CHD has been developed and published by Framingham heart Study.
heart study risk score was primarily designed to predict a 10-year risk for CHD
but subsequent analysis has revealed that the risk score is very effective in
predicting the short term cumulative risk for CHD. This is also applicable in
the context of competing risk of death from non coronary causes.
However, there are criticisms that the study's
risk model does not perform well in predicting life time risk score in younger
subjects. This is attributed to changes in risk factor status that occur over
time. Rates of hypertension and diabetes seem to increase sharply with age and
this may alter the long time risk of younger patients in an unpredictable
However, the Framingham study risk score stratified
lifetime risk quite well for women of all ages. It is opined by researchers
heart study risk score prediction model discriminates short term risk well for
men and women. But it does not identify subjects with low short term but high
life time risk for CHD.
Framingham heart study calculator
The investigators of Framingham heart study
had devised simple and practical risk scoring tables. For instance, the heart
attack calculator uses recent data to estimate a 10-year risk for myocardial
infarction and coronary death. The calculator is designed for adults aged between
20 and 79 years of age and who have not had heart disease or diabetes.
However, it should be remembered
that this is only a self assessment tool. It is advised to take regular health
care check ups with the health care professional whenever necessary.
Framingham heart study Merits
Although the Framingham heart study cohort is primarily
Caucasian, the study is applicable universally. The risk factors identified in
this group is relevant among international racial and ethnic groups even though
the distribution may vary from group to group.
- The study has the credit of producing approximately
1,200 articles in leading medical journals.
- The Framingham
heart study has yielded most important knowledge about risk factors for
cardio vascular disease such as high blood cholesterol and high blood
heart study has announced further new projects in its ongoing study of
risk for cardiovascular disease and its investigators are expanding their
research horizons into other areas such as the role of genetic factors in
Potential limitations of the Framingham heart study
- The risk estimating score sheets are only for persons
without known heart disease
- The study's risk algorithm encompasses only coronary
heart disease and not other heart and vascular diseases.
- Age is a prominent determinant of CHD risk score and
the 10-year hazards of CHD are on average high in older persons.
- The Framingham
subjects may have been motivated to modify risk factors and this in turn
could have decreased life time risk for CHD.
- The Framingham
risk assessment reveals under prediction in high risk population and over
prediction in lower risk population.
Despite its limitations, Framingham heart study has produced landmark
report on the predictive power of blood pressure, blood cholesterol level and
cigarette smoking for heart and blood vessel diseases. It has no doubt sparked a revolution in
understanding the individual and mass causes as well as the preventability of
heart attack and stroke in the US in particular and all over the world in general.
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