The role of maternal zinc nutrition in human oral clefts (OCs) is unclear. We measured plasma zinc concentrations (PZn) of case- and control-mothers to evaluate the associations between PZn and risk of OCs with and without other malformations.
Case-mothers were ascertained by the Utah Birth Defects Network and control-mothers were selected from Utah birth certificates by matching for child gender and delivery month and year. Maternal blood was collected > 1 year after the last pregnancy. PZn was available for 410 case-mothers who were divided into four subgroups; isolated cleft lip with or without cleft palate (CL/P-I, n = 231), isolated cleft palate (CP-I, n = 74), CL/P with other malformations (CLP-M, n = 42), and CP with other malformations (CP-M, n = 63). PZn was available for 447 control-mothers. The mean age of children at blood sampling was 3.7 years for all cases combined and 4.3 years for controls.
Mean PZn of all groups were similar, and low PZn (< 11.0 μmol/l) was found in 59% of cases and 62% of controls. Risk of OCs did not vary significantly across PZn quartiles for the four subgroups individually and all OC groups combined.
We previously reported that poor maternal zinc status was a risk factor for OCs in the Philippines, where OC prevalence is high and maternal PZn is low. In Utah, however, no such association was found, suggesting that poor maternal zinc status may become a risk factor only when zinc status is highly compromised.