Framingham Heart Study Risk

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 care. Framingham 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. Infact 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 cardiovascular disease.

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 University.

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 clinic.

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
  
• Cholesterol
  
• Smoking
  
• Obesity
  
• Diabetes
  
• 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 values:

• Age
  
• 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.

The Framingham 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 manner.

However, the Framingham study risk score stratified lifetime risk quite well for women of all ages. It is opined by researchers that Framingham 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 pressure.
  
  
• Framingham 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 CVD.
  
  

• 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.