title: Changes in the birth prevalence of selected birth defects after grain fortification with folic acid in the United States: findings from a multi-state population-based study.
abstract: BACKGROUND
  Observational studies and clinical trials have suggested that periconceptional use of folic acid can reduce the risk of birth defects other than neural tube defects (NTDs). Using data reported by states to the National Birth Defects Prevention Network, we examined whether folic acid fortification might have decreased the prevalence of other specific birth defects.
  
  
  METHODS
  For each of 16 birth defect categories selected for study, birth prevalence for two time periods was calculated with data submitted from a number of states in 1995-1996 ("pre-fortification") and 1999-2000 ("post-fortification"). Changes in birth prevalence between the two time periods were assessed by calculating prevalence ratios and 95% confidence intervals for each defect, and compared by maternal race/ethnicity and availability of prenatally diagnosed cases.
  
  
  RESULTS
  We confirmed previously reported reductions in the birth prevalence of NTDs. In addition, we found modest, yet statistically significant, decreases in the birth prevalence for transposition of the great arteries(12%), cleft palate only (12%), pyloric stenosis (5%), upper limb reduction defects (11%), and omphalocele (21%). More substantial subgroup decreases were observed for renal agenesis among programs that conduct prenatal surveillance (28%), for common truncus among Hispanics (45%), and for upper limb reduction defects among Hispanics (44%). There were modest yet significant increases in the prevalence of obstructive genitourinary defects (12%) and Down syndrome (7%), but not among programs conducting prenatal surveillance for these defects.
  
  
  CONCLUSIONS
  These results suggest some modest benefit from the folic acid fortification on the prevalence of a number of non-NTD birth defects.
authors.affiliation: Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Austin, 78756, USA. mark.canfield@dshs.state.tx.us
authors.forename: Mark A
authors.initials: MA
authors.lastname: Canfield
authors.forename: Julianne S
authors.initials: JS
authors.lastname: Collins
authors.forename: Lorenzo D
authors.initials: LD
authors.lastname: Botto
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Williams
authors.forename: Cara T
authors.initials: CT
authors.lastname: Mai
authors.forename: Russell S
authors.initials: RS
authors.lastname: Kirby
authors.forename: Kay
authors.initials: K
authors.lastname: Pearson
authors.forename: Owen
authors.initials: O
authors.lastname: Devine
authors.forename: Joe
authors.initials: J
authors.lastname: Mulinare
mesh_terms: D000013:Congenital Abnormalities / Q000175:diagnosis* / Q000453:epidemiology*; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D005527:Food, Fortified; D006801:Humans; D009436:Neural Tube Defects / Q000517:prevention & control; D011159:Population Surveillance; D011247:Pregnancy; D011295:Prenatal Care; D015995:Prevalence; D013997:Time Factors; D014481:United States
chemical_list: D005492:Folic Acid