The role of alcohol, tobacco, and dietary factors in upper aerogastric tract cancers: a prospective study of 10,900 Norwegian men.

Previous knowledge on risk factors for oral, pharyngeal, laryngeal, and esophageal cancer has been based mainly on case-control studies. In the present study, the impact of alcohol consumption, tobacco smoking, and dietary factors on upper aerogastric tract cancer risk was studied in a cohort of 10,960 Norwegian men followed from 1968 through 1992, in which period a total of 71 upper aerogastric tract cancers occurred. The relative risk (RR) of cancer was 3.9 (95 percent confidence interval [CI] = 2.1-7.1) for the highest consumption group of alcohol and 4.7 (CI = 1.7-13.2) for the highest smoking level, compared with the respective reference groups. Among the dietary items, high consumption of oranges was associated with reduced cancer risk (RR = 0.5, CI = 0.3-1.0), as was high consumption of bread (RR = 0.2, CI = 0.1-0.5). Frequent consumption of beef and bacon increased relative cancer risk bordering on significance. The present results are largely in accordance with previous studies. The decreased risk associated with a high intake of bread deserves further investigation.