title: [Study on N-nitroso compound in food and its relevant risk factors for esophageal cancer].
abstract: OBJECTIVE
  To study multiple risk factors of N-nitroso compounds (NOC) in high- and low-risk areas for esophageal cancer in southern China.
  
  
  METHODS
  The samples of 24-hr diets and 12-hr overnight urine were collected from 120 male healthy subjects (35-64 years old) selected by a 3-stage random cluster sample procedure in each of the high-risk area (Nanao County) and low-risk area (Lufeng County) for esophageal cancer. The urinary samples were respectively collected from undosed subjects, subjects ingested 500 mg L-proline (together with 200 mg ascorbic acid ) and subjects ingested 500 mg proline. The levels of total NOC (TNOC), N-nitrosamino acids (NAAs), volatile N-nitroso compounds and reductive ascorbic acid (VC) in the samples were measured. By unconditional logistic stepwise regression model, we analyzed the association between the multiple factors of NOC and esophageal cancer mortality. The factors included the intake and excretion levels of various kinds of NOC, the ability of NAAs endogenous formation and its inhibition by VC, and nutrition status of VC in the body.
  
  
  RESULTS
  The results of unconditional logistic stepwise regression showed that risk factors entered the model were diet TNOC content (OR 9.613, 95% CI 1.921-48.115) and urinary NAAs level after ingested VC (OR 1.137, 95 % CI 1.001-1.298).
  
  
  CONCLUSIONS
  The higher level of diet TNOC and the lower inhibition ability of NOC endogenous formation by VC were important risk factors on NOC etiology of esophageal cancer in southern China.
authors.affiliation: Shantou University Medical College, Shantou 515031, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Lin
authors.forename: Shi-Jiang
authors.initials: SJ
authors.lastname: Yu
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Zhang
authors.forename: Yong-Ning
authors.initials: YN
authors.lastname: Wu
authors.forename: Qingying
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xuerui
authors.initials: X
authors.lastname: Tan
authors.forename: Jiayi
authors.initials: J
authors.lastname: Luo
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects*; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000652:urine; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009603:Nitroso Compounds / Q000032:analysis* / Q000652:urine*; D012307:Risk Factors
chemical_list: D009603:Nitroso Compounds