title: Reduction in neural-tube defects after folic acid fortification in Canada.
abstract: BACKGROUND
  In 1998, folic acid fortification of a large variety of cereal products became mandatory in Canada, a country where the prevalence of neural-tube defects was historically higher in the eastern provinces than in the western provinces. We assessed changes in the prevalence of neural-tube defects in Canada before and after food fortification with folic acid was implemented.
  
  
  METHODS
  The study population included live births, stillbirths, and terminations of pregnancies because of fetal anomalies among women residing in seven Canadian provinces from 1993 to 2002. On the basis of published results of testing of red-cell folate levels, the study period was divided into prefortification, partial-fortification, and full-fortification periods. We evaluated the relationship between baseline rates of neural-tube defects in each province and the magnitude of the decrease after fortification was implemented.
  
  
  RESULTS
  A total of 2446 subjects with neural-tube defects were recorded among 1.9 million births. The prevalence of neural-tube defects decreased from 1.58 per 1000 births before fortification to 0.86 per 1000 births during the full-fortification period, a 46% reduction (95% confidence interval, 40 to 51). The magnitude of the decrease was proportional to the prefortification baseline rate in each province, and geographical differences almost disappeared after fortification began. The observed reduction in rate was greater for spina bifida (a decrease of 53%) than for anencephaly and encephalocele (decreases of 38% and 31%, respectively).
  
  
  CONCLUSIONS
  Food fortification with folic acid was associated with a significant reduction in the rate of neural-tube defects in Canada. The decrease was greatest in areas in which the baseline rate was high.
authors.affiliation: Laval University, Quebec, Canada. philippe.dewals@msp.ulaval.ca
authors.forename: Philippe
authors.initials: P
authors.lastname: De Wals
authors.forename: Fassiatou
authors.initials: F
authors.lastname: Tairou
authors.forename: Margot I
authors.initials: MI
authors.lastname: Van Allen
authors.forename: Soo-Hong
authors.initials: SH
authors.lastname: Uh
authors.forename: R Brian
authors.initials: RB
authors.lastname: Lowry
authors.forename: Barbara
authors.initials: B
authors.lastname: Sibbald
authors.forename: Jane A
authors.initials: JA
authors.lastname: Evans
authors.forename: Michiel C
authors.initials: MC
authors.lastname: Van den Hof
authors.forename: Pamela
authors.initials: P
authors.lastname: Zimmer
authors.forename: Marian
authors.initials: M
authors.lastname: Crowley
authors.forename: Bridget
authors.initials: B
authors.lastname: Fernandez
authors.forename: Nora S
authors.initials: NS
authors.lastname: Lee
authors.forename: Theophile
authors.initials: T
authors.lastname: Niyonsenga
mesh_terms: D002170:Canada / Q000453:epidemiology; D005492:Folic Acid / Q000008:administration & dosage*; D005527:Food, Fortified; D006801:Humans; D007231:Infant, Newborn; D009436:Neural Tube Defects / Q000453:epidemiology* / Q000517:prevention & control*; D015995:Prevalence; D014803:Vitamin B Complex / Q000008:administration & dosage*
chemical_list: D014803:Vitamin B Complex; D005492:Folic Acid