Multiple Risk Factor Intervention Trial

Multiple Risk Factor Intervention Trial (MRFIT)


A risk factor refers to a part of a certain chain of causation that leads to a given disease and is also an independent and strong predictor of the existence of excess risk. The issue of controlled experiment to arbitrate with people with high risk of experiencing heart attack because of multiple eminent risk factors began towards the end of 1960s. Main risk factors for high blood pressure, coronary heart disease, cigarette smoking and high cholesterol level in blood had already been well-known through careful observation studies. The fundamental health care question at this time was whether modification of the diet to contain lower levels of cholesterol in blood would prevent heart attack (Labarthe, 1998, p. 21).

Literature review

The Multiple Risk Factor Intervention Trial was a renowned primary prevention trial that was used to test the result of an intervention program with many factors on mortality from coronary heart disease in around 12,866 men and women of high risk aged between 35 to 57 years. According Gordis (2009), there was a random assignment of men to either a special intervention (SI) program that included counseling on cigarette smoking, stepped-care treatment for high blood pressure and advice on the foods that would lower the cholesterol level in blood, or to their day to day health care sources in the community where they were told of their conditions underwent medical assessment at the clinics of MRFIT every year (p. 34). It is however known that the trail on this hypothesis could not confirm it.

The editorial that accompanied the report indicated that unfortunately the most important question that in fact led to the setting in of this experiment was never answered by the time the experiment was over. This is enough confirmation that the answers that were sought after could not be found. It was also indicated that the results that the team came up with were not conclusive and therefore left so many questions unanswered. Another medical publication known as The Lancet indicated that the results of the MRFIT proved nothing at all. What all these people tried to imply is that the MRFIT did not prove that reducing the smoking levels, cholesterol levels and blood pressure would reduce the death risks because of heart disease (DIANE publishing company, 1992, p. 78).

After being followed up for several years, the men who were assigned in the SI group indicated a very substantial reduction in the risk level factors as compared to those that were assigned to the UC group. The most significant change of them all were realized in smoking of cigarette. According to Gordis (2009), for the men who had reported that they are smokers in the initial screening session, the rate of those who quite among the SI group was greater than the quit rate of those in UC by over 70% (p. 56). It therefore indicates that the SI group was more successful than the UC group. If you base the difference in the smoking quit rates on the smoking at the base rate, then the number is much larger. The investigators defined the baseline as the average smoking rates at both the second and the third screening sessions.

The later scenario indicated quit rates that were 100% more in the SI group than in the UC group. In fact it was reported by the investigators that the smoking quit-rate in SI-UC was more than the design goal by around 122%. This is a very great margin considering the conditions of that time. Compared to the UC group, the men in the SI group also showed a reduction in the serum cholesterol and in blood pressure. According to Meinert & Tonascia (1986), these reductions were however very minimal and could not meet the investigators expectations. Despite this, the overall difference between the two groups was considered substantial by the MRFIT (p. 67). The above illustration clearly shows huge differences that could not be ignored. They even stated that they achieved 83% of the risk factor difference in SI-UC that had been initially assumed.

In the course of the seven year period of follow up, those in the SI group demonstrated lower CHD mortality rate than the UC group. This was 17.9 deaths for every 1,000 people compared to 19.3 deaths per 1,000 in the UC group. There is a clear indication of a small difference that could be very insignificant in terms of statistics. There is no way by which the above results could support the hypothesis that risk factors such as cigarette smoking that were studied in MRFIT are causally related to the deaths caused by coronary heart disease. This is to say that even though the experiment successfully reduced the levels in the risk factors the conclusion of the investigators was rightfully indicated that the total or whole some results do not illustrate any meaningful effect on the total mortality from the intervention of the various factors that were used (Gordis, 2009, 92).

Even though the researchers reported this lack of effect, they did not over see the risk factor value intervention in reducing the total mortality. They also justified their successive belief in the importance of intervention of risk factor by indicating that the chances that intervention was ineffective looks inconstant with most of the scientific data that has been published before. According to DIANE publishing company (1995), the intervention trials on risk factor from both England and Norway were not able to demonstrate effects that could be considered statistically significant on the total mortality credited by reduction in smoking (p. 103). In addition, if there were previous data to indicate whether there are remuneration of reduction in risk factor, they there would have no need of the MRFIT. It is even indicated by the authors that the trial was aimed at testing this question.

The MRFIT project that could be termed as ambitious was conducted in the 1970s a time when mass social cultural change in behavior and health awareness was on the rise. This was also a companied by a decrease the number of incidences of stroke diseases and heart attack in the western industrial nations. With the outstanding exceptions of the Oslo study that was so successful, where the smoking and cholesterol levels were very high and the awareness on health lower than any other place, the MRFIT research was not able to illustrate considerable reduction in the rates of heart attack of the risk factors above and over the favorable changes existing in their control team (Meinert & Tonascia, 1986, p.70).

When the investigators were faced with findings that could not support the intercession hypothesis, there were various explanations they offered. They pointed figures at the constraints of the tests used within the study. According to DIANE publishing company (1995), they also added that they did not expect the major reductions in the mortality rates and the risk factor levels (p. 69). More over they also indicated that there was a possibility that some of the men in the SI group must have been unfavorably affected by the kind of treatments conducted for hypertension treatment in the intervention. This according to them must have been the reason as to why things turned out to be unfavorable compared to their expectations.

Concerning the UC group, it is important to note that the investigators recorded reductions that were more than expected in the risk factor levels as well as lower mortality rates than they expected. It is however questionable whether the kind of developments witnessed led to the inability to a wholesome beneficial intervention effect. The mortality rates in the UC groups was lower than expected and this is the reason as to why it was difficult to observe the risk of reduction factors experienced within the SI group (Labarthe, 1998, p. 45).

If you put aside all questions regarding the validity questions and various reasons that were provided by the investigators from MRFIT, their findings are marginal to the common purpose and all the results that were provided by the MRFIT (DIANE publishing company. 1992, p. 102). Generally therefore, the investigators literary refused to accept their own findings but instead began giving excuses here and there as they blame various other conditions and factors for the failure of the experiment.


The multiple risk reduction concept in the prevention of stroke and heart attack remain unchanged because of the crystal clear evidence of the fundamental role of these risk factors. With the increase in technology that has come with globalization, there is every day development and improvement in the prevention practices that are effective and sustainable. I addition we also have the improvement in the public health strategies that could go along way in the reduction of heart related complications such as hypertension and stroke. Such a situation was witnessed between 1960s and mid 1990s where the rates of coronary complications reduced drastically. This was also associated wit a reduction in the levels of risk factor and lack of health promotion to reach out to the elderly, poor, women and the young children population. Prevention in the current time is now directed to both the industrial society's multifactor risk segment and the whole country's prevention of superior multiple risk factors. This is commonly known as primordial prevention.


DIANE publishing company. (1992). Cross design synthesis: A new strategy for medical effectiveness research. Pennsylvania DIANE publishing.

DIANE publishing company. (1995). Health Benefits of smoking cessation: a report of the surgeon general. Pennsylvania: DIANE publishing.

Gordis, L. (2009). Epidemiology. Philadelphia: Elsevier Health sciences.

Labarthe, D. (1998). Epidemiology and prevention of cardiovascular diseases: a global challenge. Massachusetts: Jones & Bartlett learning.

Meinert, C. L & Tonascia, S. (1986). Clinical trials: design, conduct and analysis. New York: Oxford University press.

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