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To the Editor.—
In an article on the life expectancy of college oarsmen (220:1709, 1972), the authors had no choice but to select the controls the way they did. However, when the use of controls is essential in studies on vascular disease, each subject must be matched with a control that is similar in several respects. Since the chief causes of death in men are coronary artery disease, stroke, and hypertension, they should be matched for the risk factor in these conditions.Both subject and control should have a similar hereditary background, confirmed in their siblings. The blood pressure should be approximately the same in both, and if above 140/90 mm Hg, of similar lability (Lancet2:53,1957). If there is cardiac, brain, renal, or metabolic disease, or a history of these, it must be to the same degree in both. Cardiac symptoms, such as breathlessness or angina must also
Robinson SK. Matching Controls In Vascular Disease. JAMA. 1972;221(13):1518. doi:10.1001/jama.1972.03200260054030