Preserved foods and nasopharyngeal carcinoma: a case-control study among Singapore Chinese.

The association between the consumption of preserved foods in infancy, childhood and adulthood and the risk of nasopharyngeal carcinoma was investigated in a case-control study among Singapore Chinese: 200 cases (73% male) were compared with 406 hospital controls (71% male). Significantly increased risks were observed in association with frequent adult consumption of salted soy beans (OR 7.3 for consumption 4 or more times per week, compared with never), canned pickled vegetables (p = 0.01; OR 4.5 for 4 or more times per week), "sze chuan chye", a salted Chinese tuber, (OR 2.4 for 4 or more times per month) and "kiam chye", salted mustard greens (OR 2.7 for 4 or more times per week). A protective effect of high vitamin-E intake in adulthood was observed (OR 0.5 for the highest third of the control range, as compared with the lowest).