Are the Framingham Heart Risk Tests Useless?

by Paul Rogers on January 4, 2010

I trust everyone who had a holiday break over December is refreshed and ready for another long, hot and sweaty year — either from climate change or your exceedingly vigorous exercise regimen.

The Framingham Heart Study and Risk Factors

Commencing in 1948, the Framingham Heart Study is the largest and longest running study of cardiovascular health. The researchers recruited 5,209 men and women between the ages of 30 and 62 from the town of Framingham, Massachusetts, and began the first round of extensive physical examinations and lifestyle interviews that they would later analyze for common patterns related to CVD development. Hundreds of papers have since been published, including several risk tests that evaluate you risk of heart disease or heart attack.

The Framingham web site has this to say: “. . . has led to the identification of the major CVD risk factors – high blood pressure, high blood cholesterol, smoking, obesity, diabetes, and physical inactivity.”

Strangely, none of the Framingham risk tests include physical activity (or inactivity) as  primary risk factor in the calculators even though all of the other factors listed above are included  in one or more  risk tests. Perhaps physical activity, or, more precisely, lack of, is not considered a primary factor because its effects may be reflected in lower LDL cholesterol, high HDL cholesterol, low body mass index and so on.

But no, this is not correct. Enough work has been done to establish that physical activity that leads to cardiovascular fitness changes the dynamics of heart function, and that this has unique protective factors in its own right. Measures such as heart rate reserve (max heart rate less resting heart rate) and VO2 max are independent of measures of cardiovascular risk in some studies.

Even a recent publication in the Journal of Cardiology found that:

PA (physical activity) was associated with CVD, independent of the common cardiometabolic risk factors, in men and women. The association between PA and CVD risk was not mediated by the measured cardiometabolic risk factors.

I emailed a few different web places on this subject, including the American Heart Association web site but got no relevant reply. How can these formal risk calculators be of use when a major risk factor is excluded?

McGuire KA, Janssen I, Ross R. Ability of physical activity to predict cardiovascular disease beyond commonly evaluated cardiometabolic risk factors. Am J Cardiol. 2009 Dec 1;104(11):1522-6.

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