Reduction in neural-tube defects after folic acid fortification in Canada

Philippe De Wals, Fassiatou Tairou, Margot I. Van Allen, Soo Hong Uh, R. Brian Lowry, Barbara Sibbald, Jane A. Evans, Michiel C. Van Den Hof, Pamela Zimmer, Marian Crowley, Bridget Fernandez, Nora S. Lee, Theophile Niyonsenga

Research output: Contribution to journalArticle

518 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)135-142
Number of pages8
JournalNew England Journal of Medicine
Volume357
Issue number2
DOIs
Publication statusPublished - 2007
Externally publishedYes

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Neural Tube Defects
Folic Acid
Canada
Parturition
Anencephaly
Encephalocele
Food
Spinal Dysraphism
Stillbirth
Live Birth
Confidence Intervals
Pregnancy
Population

Cite this

De Wals, P., Tairou, F., Van Allen, M. I., Uh, S. H., Lowry, R. B., Sibbald, B., ... Niyonsenga, T. (2007). Reduction in neural-tube defects after folic acid fortification in Canada. New England Journal of Medicine, 357(2), 135-142. https://doi.org/10.1056/NEJMoa067103
De Wals, Philippe ; Tairou, Fassiatou ; Van Allen, Margot I. ; Uh, Soo Hong ; Lowry, R. Brian ; Sibbald, Barbara ; Evans, Jane A. ; Van Den Hof, Michiel C. ; Zimmer, Pamela ; Crowley, Marian ; Fernandez, Bridget ; Lee, Nora S. ; Niyonsenga, Theophile. / Reduction in neural-tube defects after folic acid fortification in Canada. In: New England Journal of Medicine. 2007 ; Vol. 357, No. 2. pp. 135-142.
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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.",
author = "{De Wals}, Philippe and Fassiatou Tairou and {Van Allen}, {Margot I.} and Uh, {Soo Hong} and Lowry, {R. Brian} and Barbara Sibbald and Evans, {Jane A.} and {Van Den Hof}, {Michiel C.} and Pamela Zimmer and Marian Crowley and Bridget Fernandez and Lee, {Nora S.} and Theophile Niyonsenga",
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De Wals, P, Tairou, F, Van Allen, MI, Uh, SH, Lowry, RB, Sibbald, B, Evans, JA, Van Den Hof, MC, Zimmer, P, Crowley, M, Fernandez, B, Lee, NS & Niyonsenga, T 2007, 'Reduction in neural-tube defects after folic acid fortification in Canada', New England Journal of Medicine, vol. 357, no. 2, pp. 135-142. https://doi.org/10.1056/NEJMoa067103

Reduction in neural-tube defects after folic acid fortification in Canada. / De Wals, Philippe; Tairou, Fassiatou; Van Allen, Margot I.; Uh, Soo Hong; Lowry, R. Brian; Sibbald, Barbara; Evans, Jane A.; Van Den Hof, Michiel C.; Zimmer, Pamela; Crowley, Marian; Fernandez, Bridget; Lee, Nora S.; Niyonsenga, Theophile.

In: New England Journal of Medicine, Vol. 357, No. 2, 2007, p. 135-142.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Reduction in neural-tube defects after folic acid fortification in Canada

AU - De Wals, Philippe

AU - Tairou, Fassiatou

AU - Van Allen, Margot I.

AU - Uh, Soo Hong

AU - Lowry, R. Brian

AU - Sibbald, Barbara

AU - Evans, Jane A.

AU - Van Den Hof, Michiel C.

AU - Zimmer, Pamela

AU - Crowley, Marian

AU - Fernandez, Bridget

AU - Lee, Nora S.

AU - Niyonsenga, Theophile

PY - 2007

Y1 - 2007

N2 - 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.

AB - 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.

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De Wals P, Tairou F, Van Allen MI, Uh SH, Lowry RB, Sibbald B et al. Reduction in neural-tube defects after folic acid fortification in Canada. New England Journal of Medicine. 2007;357(2):135-142. https://doi.org/10.1056/NEJMoa067103