Moderate Prenatal Cadmium Exposure and Adverse Birth Outcomes: a Role for Sex-Specific Differences?

Background/Aim: Studies on the effects of moderate prenatal exposure to cadmium (Cd) on birth outcomes have been contradictory and it has been suggested that effects may be partly masked by sex-specific effects. Our aim was to examine the association of Cd exposure in a large group of pregnant women with birth outcomes in the whole group of participants and by sex. Methods: Pregnant women were enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). Whole blood samples for singleton pregnancies with a live birth were analysed for Cd (n = 4191). Data collected on the infants included anthropometric variables and gestational age at delivery. Data were analysed using SPSS v18. Results: There were adverse associations of maternal blood Cd level with birthweight (unstandardized B coefficient -62.7 g, 95% CI -107.0, -18.4) and crown-heel length (-0.28 cm, 95% CI -0.48, -0.07) in adjusted regression models. On stratification by sex, maternal blood Cd level was adversely associated with birthweight (-87.1 g, 95% CI -144.8, -29.4), head circumference (-0.22 cm, 95% CI -0.39, -0.04), and crown-heel length (-0.44 cm, 95% CI -0.71, -0.18) in girls but not in boys in adjusted regression models. Conclusion: In these pregnant women with moderate prenatal Cd exposure there evidence of adverse associations with birth anthropometry variables in the whole group. However, there was evidence of associations with anthropometric variables in girls that were not evident in boys. Sex-specific effects require further investigation in large cohorts as a possible contributor to the lack of associations generally found in mixed-sex studies.