Maternal plasma zinc and the risk of isolated oral clefts in children in Utah

Abstract

We reported that low plasma zinc levels were common in Filipino women of reproductive age and higher plasma zinc was associated with a lower risk for cleft lip with or without cleft palate (CL/P) in their children. An IRB approved case-control study was conducted in 169 case-mothers of children with CL/P and 369 control-mothers of unaffected children in Utah. The mean age of children was 4.1 (± 2.1, SD) years old, when maternal blood samples were obtained for zinc assay between 2000 and 2005. Odds ratios (OR) of the relative risk of CL/P were calculated for plasma zinc quartiles. The mean plasma zinc of case-mothers (11.0 ± 2.1 μmol/L) was similar to that in control-mothers (11.3 ± 5.9 μmol/L; p =0.59). Low plasma zinc (< 11.0 μmol/L) was found in 50% of cases and in 56% of controls (p = 0.10). The ORs for CL/P, adjusted for potential confounding factors, were similar for plasma zinc quartiles: 1.0 (lowest quartile reference), 0.67 (95% CI, 0.37 – 1.21), 1.00 (0.57 – 1.79), and 0.91 (0.51 – 1.65) (p trend = 0.92). We were able to detect that poor zinc status is a risk factor for oral clefts in Filipino mothers, where the overall prevalence of CL/P is high and plasma zinc was generally low. In this study, however, we did not detect such an association in mothers with relatively high plasma zinc, suggesting that poor zinc status is considered as a risk only when the status is severely compromised.