Preserved foods and nasopharyngeal carcinoma: A case‐control study among singapore chinese

Abstract

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).

Adulthood consumption of preserved and nonpreserved vegetables and the risk of nasopharyngeal carcinoma: A systematic review

“…34 Twelve studies stated that the NPC cases under study were histologically confirmed. 14,31-34,37-42 The source of controls was populationbased in 11 studies, 12,14,[32][33][34][35][36][37]40,42,43 hospital-based in 4 studies 13,31,38,39 and not stated in 1 study. 41 Thirteen studies were conducted among Chinese residents of Asian countries; of these, 9 were conducted in China 12,31,34,35,[37][38][39][40][41] and the others were carried out in Taiwan, 33 Malaysia, 14,43 and Singapore.…”

“…41 Thirteen studies were conducted among Chinese residents of Asian countries; of these, 9 were conducted in China 12,31,34,35,[37][38][39][40][41] and the others were carried out in Taiwan, 33 Malaysia, 14,43 and Singapore. 13 The remaining 3 studies were conducted in the United States, 36 Algeria, 32 and Tunisia. 42 Dietary intake information was collected using a food-frequency questionnaire in 12 studies, [12][13][14]31,[33][34][35][36][37][40][41][42] a dietary history questionnaire in 2 studies, 38,39 and dietary recall in 1 study.…”

“…13 The remaining 3 studies were conducted in the United States, 36 Algeria, 32 and Tunisia. 42 Dietary intake information was collected using a food-frequency questionnaire in 12 studies, [12][13][14]31,[33][34][35][36][37][40][41][42] a dietary history questionnaire in 2 studies, 38,39 and dietary recall in 1 study. 43 In 1 study, the type of instrument used to assess food intake was not specified.…”

“…13,33 Further, only 8 studies stated that the response rate among the controls was at least 70%. [12][13][14][33][34][35][36]43 Only 1 study explicitly stated that the instrument used to assess dietary intake was validated. 36 This study was conducted in the United States and did not contribute to the preserved vegetable intake analyses.…”

“…The consumption of Cantonese-style salted fish has consistently been found to be associated with an increased risk of NPC. [8][9][10][11][12][13][14] Cantonese-style salted fish contains high levels of volatile nitrosamines produced during the preservation process, 15,16 which have been shown in animal and laboratory studies to be both mutagenic and carcinogenic. 17 Cantonese-style salted fish, however, is not frequently consumed in many communities of Southern China.…”