Hot and cold mate drinking and esophageal cancer in Paraguay.

A hospital-based case-control study, including 131 cases of esophageal cancer and 381 controls, was carried out in Paraguay to investigate the role of hot and cold mate drinking in esophageal cancer risk. Detailed information on mate drinking and on tobacco smoking, alcohol consumption, and dietary habits was obtained by interview. Amount and duration of cold or hot mate drinking were not associated with esophageal cancer risk. However, temperature at which mate was drunk was significantly associated with risk. As compared to drinkers of warm or hot mate, drinkers of very hot mate had an increased risk for esophageal cancer even after adjusting for the strong effects of alcohol and tobacco consumption (adjusted odds ratio = 2.4; 95% confidence interval = 1.3-4.3). This effect seemed to be mainly due to the temperature at which mate cocido (one of the two ways in which hot mate is prepared) was drunk (odds ratio = 6.5; 95% confidence interval = 3.2-12.2). As expected, very strong dose-response associations were found for alcohol consumption and cigarette smoking. After correcting for these and the consumption of other food groups, diets rich in fats and red meats, especially beef, were associated with esophageal cancer risk. In conclusion, the findings from this study suggest that cold mate drinking does not increase the risk of esophageal cancer. This study identifies the very hot temperature at which mate is drunk, and not the amount or the duration, as an important risk factor for esophageal cancer in this population. Alcohol drinking and tobacco smoking remain, nevertheless, the main risk factors for esophageal cancer in Paraguay.