title: Dietary components related to N-nitroso compound formation: a prospective study of adult glioma.
abstract: BACKGROUND
  N-nitroso compounds (NOC) are found in processed meat and are formed endogenously from intake of nitrite and nitrate. Endogenous NOC formation is antagonized by nitrosation inhibitors in fruit and vegetables (e.g., vitamin C) and promoted by heme in red meat. It has been hypothesized that a diet resulting in high exposure to NOCs increases adult glioma risk.
  
  
  METHODS
  Using proportional hazards models, we tested this hypothesis among 545,770 participants in the prospective NIH-AARP Diet and Health Study, which assessed dietary intake at baseline (1995-1996) with a comprehensive food frequency questionnaire, and at ages 12 to 13 years with an abbreviated food frequency questionnaire.
  
  
  RESULTS
  During follow-up through 2003, 585 participants were diagnosed with glioma. We found no significant trends in glioma risk for consumption of processed or red meat, nitrate, or vitamin C or E. We found significant positive trends for nitrite intake from plant sources (hazard ratio for quintile 5 versus quintile 1, 1.59; 95% confidence interval, 1.20-2.10; P for trend = 0.028) and, unexpectedly, for fruit and vegetable intake (hazard ratio, 1.42; 95% confidence interval, 1.08-1.86; P for trend = 0.0081). Examination of interactions between dietary intakes (e.g., nitrite and vitamin C) and a limited analysis of diet at ages 12 to 13 years provided no support for the NOC hypothesis.
  
  
  CONCLUSIONS
  Our results suggest that consumption of processed or red meat, nitrite, or nitrate does not increase adult glioma risk, and that consumption of fruit and vegetables, vitamin C, or vitamin E does not reduce risk.
  
  
  CONCLUSIONS
  Our results, in agreement with the only previous prospective analysis, cast doubt on the NOC hypothesis in relation to dietary intake and adult glioma risk.
authors.affiliation: Yale School of Public Health, 60 College Street, P.O. Box 208034, New Haven, CT 06520-8034, USA. robert.dubrow@yale.edu
authors.forename: Robert
authors.initials: R
authors.lastname: Dubrow
authors.forename: Amy S
authors.initials: AS
authors.lastname: Darefsky
authors.forename: Yikyung
authors.initials: Y
authors.lastname: Park
authors.forename: Susan T
authors.initials: ST
authors.lastname: Mayne
authors.forename: Steven C
authors.initials: SC
authors.lastname: Moore
authors.forename: Briseis
authors.initials: B
authors.lastname: Kilfoy
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Cross
authors.forename: Rashmi
authors.initials: R
authors.lastname: Sinha
authors.forename: Albert R
authors.initials: AR
authors.lastname: Hollenbeck
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000378:metabolism*; D004032:Diet; D005260:Female; D005638:Fruit; D005910:Glioma / Q000453:epidemiology* / Q000378:metabolism*; D006801:Humans; D008297:Male; D008460:Meat; D008875:Middle Aged; D009603:Nitroso Compounds / Q000378:metabolism*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014675:Vegetables
chemical_list: D009603:Nitroso Compounds