title: Maternal vitamin B-6 and folate status and risk of oral cleft birth defects in the Philippines.
abstract: BACKGROUND
  Vitamin deficiencies induce oral clefts in animal experiments, but the role of specific nutrients in human oral clefts is uncertain.
  
  
  METHODS
  Associations between maternal vitamin B-6 and folate status and risk of nonsyndromic cleft lip, with or without cleft palate (CL/P), were examined in case-control studies at two sites in the Philippines--Negros Occidental and Davao. Cases were mothers of affected children and control mothers were those who had no children with oral clefts.
  
  
  RESULTS
  The risk of having a CL/P-affected child increased with increasing tertile of vitamin B-6 deficiency in both Negros Occidental and Davao (odds ratios [ORs] and 95% confidence intervals [CIs] for sites combined = 1.0 [reference], OR, 2.94; 95% CI, 1.51-5.73; OR, 4.98; 95% CI, 2.56-9.67). Poor B-6 status had a stronger association with CL/P among mothers with lower versus higher plasma folate levels. Increasing tertiles of plasma folate were marginally associated with an increased risk of clefts in both sites combined (1.0 [reference]; OR, 1.58; 95% CI, 0.93-2.68; OR, 1.59; 95% CI, 0.94-2.70). Increasing tertiles of erythrocyte folate were associated with a decreased risk of CL/P in Negros Occidental (1.0 [reference]; OR, 0.34; 95% CI, 0.13-0.90; OR, 0.46; 95% CI, 0.20-1.09) and an increased risk in Davao (1.0 [reference]; OR, 1.23; 95% CI, 0.54-2.81; OR, 4.85; 95% CI, 2.24-10.50). The inconsistent associations between folate status and CL/P risk appeared to be a result of statistical interaction between folate, vitamin B-6, and case-control status that produced different results in study areas of higher versus lower prevalence of vitamin B-6 deficiency.
  
  
  CONCLUSIONS
  Poor maternal vitamin B-6 status was consistently associated with an increased risk of CL/P at two sites in the Philippines. Folate-CL/P associations were inconsistent and may be related to the vitamin B-6 status or other characteristics of the populations under study.
authors.affiliation: Department of Nutrition and Food Sciences, Utah State University, Logan, Utah, USA. rmunger@cc.usu.edu
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Munger
authors.forename: Howerde E
authors.initials: HE
authors.lastname: Sauberlich
authors.forename: Christopher
authors.initials: C
authors.lastname: Corcoran
authors.forename: Buena
authors.initials: B
authors.lastname: Nepomuceno
authors.forename: Sandra
authors.initials: S
authors.lastname: Daack-Hirsch
authors.forename: Florentino S
authors.initials: FS
authors.lastname: Solon
mesh_terms: D016022:Case-Control Studies; D002971:Cleft Lip / Q000378:metabolism*; D002972:Cleft Palate / Q000378:metabolism*; D005260:Female; D005492:Folic Acid / Q000378:metabolism*; D006801:Humans; D008297:Male; D009035:Mothers; D010679:Philippines / Q000453:epidemiology; D012307:Risk Factors; D025101:Vitamin B 6 / Q000378:metabolism*
chemical_list: D025101:Vitamin B 6; D005492:Folic Acid