title: Plasma zinc concentrations of mothers and the risk of nonsyndromic oral clefts in their children: a case-control study in the Philippines.
abstract: BACKGROUND
  Findings from animal experiments suggest a link between poor maternal zinc status and increased risk of oral clefts in offspring; however, there are few human studies on this issue.
  
  
  METHODS
  A case-control study was conducted using 74 case mothers of children with nonsyndromic cleft lip with or without cleft palate (CL/P, n=57) or cleft palate alone (CP, n=17), and 283 control mothers of unaffected children recruited in the Philippines in early 2003. Maternal zinc status was assessed by determining plasma zinc concentrations a mean of 5 years after delivery of the index child. Odds ratios (ORs) of estimates of the relative risk of oral clefts were calculated for quartiles of maternal plasma zinc concentrations.
  
  
  RESULTS
  The mean plasma zinc concentration of CL/P case mothers (9.6+/-1.2, SD micromol/l) was significantly lower than that in control mothers (10.1+/-1.6 micromol/l; P<0.05). Low plasma zinc concentrations (<11.0 micromol/l) were found in 88% and 94% of CL/P and CP case mothers, respectively, and in 72% of controls (P<0.05). The ORs for CL/P and CP combined, adjusted for potential confounding factors, decreased with increasing quartile of plasma zinc as follows: 1.0 (lowest quartile reference), 0.83 (95% confidence interval 0.37-1.89), 0.70 (0.31-1.68), and 0.26 (0.10-0.70) (P trend=0.008).
  
  
  CONCLUSIONS
  Low plasma zinc concentrations were common in Filipino women of reproductive age, and higher plasma zinc concentrations were associated with a lower risk for oral clefts in their children.
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Al 35294, USA. tamurat@uab.edu
authors.forename: Tsunenobu
authors.initials: T
authors.lastname: Tamura
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Munger
authors.forename: Christopher
authors.initials: C
authors.lastname: Corcoran
authors.forename: Jocelyn Y
authors.initials: JY
authors.lastname: Bacayao
authors.forename: Buena
authors.initials: B
authors.lastname: Nepomuceno
authors.forename: Florentino
authors.initials: F
authors.lastname: Solon
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002971:Cleft Lip / Q000097:blood* / Q000453:epidemiology / Q000209:etiology; D002972:Cleft Palate / Q000097:blood* / Q000453:epidemiology / Q000209:etiology; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D016017:Odds Ratio; D010679:Philippines / Q000453:epidemiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012307:Risk Factors; D015032:Zinc / Q000097:blood* / Q000172:deficiency*
chemical_list: D015032:Zinc