title: Folic acid supplementation influences the distribution of neural tube defect subtypes: A registry-based study.
abstract: Periconceptional folic acid (FA) reduces neural tube defect (NTD) risk, but seems to have a varying effect per NTD subtype. We aimed to study the effect of FA supplementation on NTD subtype distribution using data from EUROCAT Northern Netherlands. We included all birth types with non-syndromal NTDs born in 1997-2012. By Fisher's exact test we analyzed possible differences in NTD subtype distribution between a correct FA supplementation group and incorrect FA supplementation group. We found proportionally fewer cervical/thoracic spina bifida cases and more lumbar/sacral spina bifida cases in the correct FA supplementation group, irrespective of the presence of the main NTD risk factors. The effect on NTD subtype distribution was only seen when FA supplementation was started before conception. We conclude that FA not only prevents the occurrence of a significant proportion of NTDs, but might also decrease the severity of NTDs, as long as supplementation is started before conception.
authors.affiliation: Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: J E H
authors.initials: JE
authors.lastname: Bergman
authors.affiliation: Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Otten
authors.affiliation: Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: J B G M
authors.initials: JB
authors.lastname: Verheij
authors.affiliation: Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: j.e.h.van.kammen@umcg.nl.
authors.forename: H E K
authors.initials: HE
authors.lastname: de Walle
mesh_terms: D000757:Anencephaly / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D016742:Preconception Care / Q000379:methods*; D011247:Pregnancy; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D016135:Spinal Dysraphism / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D005492:Folic Acid
keywords: Anencephaly; Encephalocele; Folic acid; Neural tube defect; Severity; Spina bifida