title: Low maternal vitamin B(12) is a risk factor for neural tube defects: a meta-analysis.
abstract: OBJECTIVE
  The objective of this study was to assess whether low level of maternal vitamin B(12) is associated with an increased risk of fetal neural tube defects (NTDs), in order to contribute to research on further reduction of NTDs under a background of mandatory folic acid (FA) fortification.
  
  
  METHODS
  A meta-analysis was conducted. We retrieved and evaluated the studies published on the risk of low level of maternal vitamin B(12) for NTDs. The homogeneity of the studies was examined using the forest graph. Meta-analysis was applied to calculate the odds ratio (OR) of fetal NTDs in relation to low maternal B(12) and its 95% confidence interval (CI).
  
  
  RESULTS
  We identified nine published articles including 567 cases and 1566 controls in the meta-analysis. All the studies selected were homogeneous according to the forest graph (χ(2) = 15.05, P < 0.1). The estimated OR value of fetal NTDs in relation to low maternal B(12) was 2.41 (95% CI: 1.90-3.06).
  
  
  CONCLUSIONS
  Low maternal B(12) status could be an important risk factor for the development of fetal NTDs. The addition of synthetic B(12) to current recommendations for periconceptional FA tablet supplements or FA-fortified foods should be considered.
authors.affiliation: Department of Epidemiology and Health Statistics, Shandong University, Jinan, Shandong, China. zhiping9312@yahoo.com.cn
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Wang
authors.forename: Xiao-Xiao
authors.initials: XX
authors.lastname: Shang
authors.forename: Zhong-Tang
authors.initials: ZT
authors.lastname: Zhao
mesh_terms: D005260:Female; D005843:Geography; D006801:Humans; D007231:Infant, Newborn; D039382:Maternal Nutritional Physiological Phenomena; D008431:Maternal-Fetal Exchange / Q000502:physiology; D009436:Neural Tube Defects / Q000453:epidemiology* / Q000209:etiology*; D009752:Nutritional Status / Q000502:physiology; D016017:Odds Ratio; D011247:Pregnancy; D012307:Risk Factors; D014805:Vitamin B 12 / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000150:complications* / Q000453:epidemiology*
chemical_list: D014805:Vitamin B 12