title: Maternal dietary intake of nitrates, nitrites and nitrosamines and selected birth defects in offspring: a case-control study.
abstract: BACKGROUND
  Dietary intake of nitrates, nitrites, and nitrosamines can increase the endogenous formation of N-nitroso compounds in the stomach. Results from animal studies suggest that these compounds might be teratogenic. We examined the relationship between maternal dietary intake of nitrates, nitrites (including plant and animal sources as separate groups), and nitrosamines and several types of birth defects in offspring.
  
  
  METHODS
  For this population-based case-control study, data from a 58-question food frequency questionnaire, adapted from the short Willett Food Frequency Questionnaire and administered as part of the National Birth Defects Prevention Study (NBDPS), were used to estimate daily intake of dietary nitrates, nitrites, and nitrosamines in a sample of 6544 mothers of infants with neural tube defects (NTD)s, oral clefts (OC)s, or limb deficiencies (LD)s and 6807 mothers of unaffected control infants. Total daily intake of these compounds was divided into quartiles based on the control mother distributions. Odds ratios (OR)s and 95% confidence intervals (CI)s were estimated using logistic regression; estimates were adjusted for maternal daily caloric intake, maternal race-ethnicity, education, dietary folate intake, high fat diet (>30% of calories from fat), and state of residence.
  
  
  RESULTS
  While some unadjusted ORs for NTDS had 95% (CI)s that excluded the null value, none remained significant after adjustment for covariates, and the effect sizes were small (adjusted odds ratios [aOR]<1.12). Similar results were found for OCs and LDs with the exception of animal nitrites and cleft lip with/without cleft palate (aORs and CIs for quartile 4 compared to quartile 1 =1.24; CI=1.05-1.48), animal nitrites and cleft lip (4th quartile aOR=1.32; CI=1.01-1.72), and total nitrite and intercalary LD (4th quartile aOR=4.70; CI=1.23-17.93).
  
  
  CONCLUSIONS
  Overall, odds of NTDs, OCs or LDs did not appear to be significantly associated with estimated dietary intake of nitrate, nitrite, and nitrosamines.
authors.affiliation: Department of Epidemiology and Biostatistics, The Texas A&M Health Science Center School of Rural Public Health, MS 1266 TAMU, College Station, TX 77843-1266, USA. jdbrender@srph.tamhsc.edu.
authors.forename: John C
authors.initials: JC
authors.lastname: Huber
authors.forename: Jean D
authors.initials: JD
authors.lastname: Brender
authors.forename: Qi
authors.initials: Q
authors.lastname: Zheng
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Sharkey
authors.forename: Ann M
authors.initials: AM
authors.lastname: Vuong
authors.forename: Mayura U
authors.initials: MU
authors.lastname: Shinde
authors.forename: John S
authors.initials: JS
authors.lastname: Griesenbeck
authors.forename: Lucina
authors.initials: L
authors.lastname: Suarez
authors.forename: Peter H
authors.initials: PH
authors.lastname: Langlois
authors.forename: Mark A
authors.initials: MA
authors.lastname: Canfield
authors.forename: Paul A
authors.initials: PA
authors.lastname: Romitti
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Weyer
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002971:Cleft Lip / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D002972:Cleft Palate / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D016001:Confidence Intervals; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009436:Neural Tube Defects / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D009566:Nitrates / Q000008:administration & dosage* / Q000009:adverse effects; D009573:Nitrites / Q000008:administration & dosage* / Q000009:adverse effects; D009602:Nitrosamines / Q000008:administration & dosage* / Q000009:adverse effects; D016017:Odds Ratio; D011247:Pregnancy; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines; D005492:Folic Acid