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 μmol/l) was significantly lower than that in control mothers (10.1 ± 1.6 μmol/l; P < 0.05). Low plasma zinc concentrations (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. Birth Defects Research (Part A), 2005.