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Objective: To investigate risk factors for medullary thyroid cancer (MTC). Methods: We conducted a pooled analysis of 14 case-control studies from Europe, North America, and Asia, including 67 medullary cancers (43 women and 24 men) diagnosed in ten studies. Of the original 4776, we selected five controls per case matched on study, gender, and age. The pooled odds ratios (OR) were estimated using conditional logistic regression. Results: Education, weight, and body mass were not associated with MTC, but a significant positive relationship was seen with height (OR = 2.6 for highest vs lowest tertile). Significant excess risks were associated with a history of thyroid nodules (OR = 12), hypertension (OR = 2.3), gallbladder disease (OR = 4.3), and allergies (OR = 2.2). Among current smokers, a decreased risk of MTC was observed with increasing number of cigarettes. The risk was significantly elevated among women having a first birth after age 25 years, but no clear pattern emerged for other reproductive factors. Conclusions: Although the number of MTC was small, we detected several significant associations, including prior thyroid and other diseases.

M ANY WORKERS” HAVE STUDIED THE effects on cardiac function of modifying the concentration of blood potassium. These investigations have been carried out in experimental animals of various species, as well as in man, in both normal and pathologic conditions. It has been proved that an increase of extracellular potassium over the normal limits leads to slowing of the cardiac rate, decrease of the contractile force of the myocardium, to atrio-ventricular block, and to disturbances of intraventricular conductivitv.�’#{176} Except for the treatment of certain arrhythmias, especially extrasystoles and digitalis toxicity with KC 1, the results of electrophysiologic studies concerning the action of potassium on myocardial function have not found significant application in cardiac therapeutics. It is true that there are clinical studies which indicate that a decrease of activity of an idioventricular focus with resulting Adams-Stokes crises may appear in cases of acidosis with hyperkalemia in patients with complete A-V block.” In order to combat Adams-Stokes crises in these cases, molar sodium lactate was suggested for treatment.’2 More recently, Tobian” has described eight clinical cases with A-V block, with frequent Adams-Stokes crises, in whom a reduction of blood potassium with the aid of chlorothiazide led to the disappearance of the Adams-Stokes crises. It must be noted that in all these cases the blood pH was not altered.