To the Editor:--Investigators interested in the health of populations continue to look for biologic pathways that can connect some of the social determinants of health with the production of disease. [1]The results reported by Rosenfeld et al. [2]show that plasma fibrinogen concentration increases in human subjects after the infusion of epinephrine, cortisol, or glucagon may add to the understanding of how certain social factors are biologically related to the development of coronary artery disease.

Data from the Northwick and Framingham studies [3,4]and other epidemiologic evidence reviewed by Ernst [5]indicate that plasma fibrinogen concentrations can be used to predict coronary artery disease with predictive power as high as more generally accepted risk factors.

Marmot et al. [6]have shown that mortality from coronary artery disease is inversely related to employment grade with a relative risk more than three times greater in the lowest grade of employment compared with the highest grade. Markowe et al. [7]reported significant differences in plasma fibrinogen concentrations between men in the lowest grades of employment and those in the highest classifications. They also demonstrated a positive correlation between the workers' fibrinogen concentrations and the stress of their respective jobs as determined by a questionnaire composed of items that had been shown to identify stress related to increased risk of coronary artery disease.

Combining the findings of Rosenfeld et al. with the epidemiologic data prompts the speculation that lower social class and employment grade produce stress leading to an increase in circulating epinephrine, which results in increased plasma fibrinogen concentration, which in turn is predictive of coronary artery disease and perhaps causally related.

John C. Ribble, M.D., Visiting Scholar, New England Medical Center #345, 750 Washington Street, Boston, Massachusetts 02111.

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