title: Habitual consumption of soy products and risk of nasopharyngeal carcinoma in Chinese adults: a case-control study.
abstract: OBJECTIVE
  Many studies have shown a negative association between the consumption of soy products and the risk of some cancers, but little is known about the effect of soy consumption on nasopharyngeal carcinoma. We assessed the association between the consumption of soy products on nasopharyngeal carcinoma risk in Chinese individuals.
  
  
  METHODS
  This case-control study included 600 (448 males and 152 females) incident cases of nasopharyngeal carcinoma, and an equal number of controls, matched according to gender, age (± 3 y) and household type to the nasopharyngeal carcinoma cases. All subjects were recruited from hospitals in Guangzhou, China. A face-to-face interview was conducted with each study individual to collect general information and habitual dietary intake using a 78-item quantitative food-frequency questionnaire. Odds ratios and their 95% confidence intervals were estimated using conditional logistic regression analyses.
  
  
  RESULTS
  The median intakes of soy foods (in protein) were 0.5/0.5, 1.4/1.7, 2.7/3.3 and 6.1/7.7 (male/female) g/d in the quartiles 1 to 4. Both univariate and multivariate analyses showed no significant association between the consumption of soy proteins or soy isoflavones and the risk of nasopharyngeal carcinoma. The adjusted odds ratios (95% confidence intervals) between extreme quartiles were 0.97 (0.66-1.45) for soy proteins and 0.97 (0.66-1.42) for total isoflavones. Null associations were also observed between intake of the individual isoflavones daidzein, genistein and glycitein and NPC risk, with adjusted odds ratios for the extreme quartiles ranging between 0.73 and 1.23.
  
  
  CONCLUSIONS
  Habitual consumption of soy products had no significant effect on the risk of nasopharyngeal carcinoma in Chinese adults with a relatively low intake.
authors.affiliation: Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China ; Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: Yuan-ting
authors.initials: YT
authors.lastname: Liu
authors.forename: Yu-ying
authors.initials: YY
authors.lastname: Fan
authors.forename: Chun-hua
authors.initials: CH
authors.lastname: Xu
authors.forename: Xiao-ling
authors.initials: XL
authors.lastname: Lin
authors.forename: Yun-kai
authors.initials: YK
authors.lastname: Lu
authors.forename: Xing-lan
authors.initials: XL
authors.lastname: Zhang
authors.forename: Cai-xia
authors.initials: CX
authors.lastname: Zhang
authors.forename: Yu-ming
authors.initials: YM
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D002277:Carcinoma; D016022:Case-Control Studies; D002681:China; D003710:Demography; D004522:Educational Status; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000009:adverse effects; D008019:Life Style; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000209:etiology*; D012307:Risk Factors; D045730:Soy Foods / Q000009:adverse effects*
chemical_list: D007529:Isoflavones