Regional variation in ischemic heart disease: a possible missing risk factor?

Response I Suspicions that oxygen was toxic had indeed led will continue to be demanded to settle thera. ' to its declining clinical use before the National peutic controversies. Cooperative Study (NCS) randomized trial, but We agree with Toth that it would be valuable controversy was still widespread before 1956, to determine the true value of RCTs in settling and many clinicians were unpersuaded. The disputes and affecting clinical practice. We also / results of the trial gave convincing scientific believe it would he valuable to develop less ! evidence of the toxicity, and the subsequent costly, alternative research methods that ma), i textbook recommendations and media publicity with suitable criteria [I-31, sometimes be equally j helped contribute to a further decline in use of or almost equally valid. oxygen. Toth claims that "later research failed to ROBERT M. JACOB SO^ substantiate the 1956 trial", hut he does not cite Mrzyu C I ~ ~ , ~ Rucl~erirr. 112'. C S A , the research, and we are not aware of what it may have been. Toth correctly points out that ALVAN R. FEINSTEIX deprivation of supplemental oxygen for premaYule L ~ i r e r v i ~ j .Schooi OJ ,wedicinp .Vr,t' Hilren. CT 06.716. C S A , ture infants may have led to increased mortality I