Association and interaction between metal aluminum and iron exposure and the risk of offspring’ congenital heart defects occurrence in northwestern China

The purpose of this study is to explore the levels of aluminum (Al) and iron (Fe) levels in maternal peripheral blood (MB) and cord blood (CB) and the relationship to the risk of congenital heart defects (CHDs) in the offspring. This matched-based birth cohort study with 194 controls and 97 CHDs-cases (proportion = 2:1) was included in this study. Serum concentrations of Al and Fe were measured by inductively coupled plasma mass spectroscopy. Conditional logistic regression model was employed to evaluate the influence of Al/Fe and its interaction on risk of fetal CHDs, adjusted for confounders. Compared to the low quartiles of Al level in CB, risk differences were significantly detected in the highest quartiles of Al in total CHDs (aOR = 2.826, 95% CI: 1.009–7.266) and isolated CHDs (aOR = 10.713, 95% CI: 1.017–112.851). A significant dose-effect was observed between the Al level and total CHDs in both MB and CB (Ptrend < 0.05). Notably, co-exposure to high Al and Fe elicited a strong correlation on fetal heart development than low Al and low Fe in CB of total CHDs (aOR = 5.273, 95% CI: 1.897–14.657), multiple CHDs (aOR = 7.820, 95% CI: 1.672–36.588), septal defects (aOR = 4.747, 95% CI: 1.428–15.780) and PDA (aOR = 13.147, 95% CI: 2.415–71.565). Our data support that Al exposure(≥2.408 mg/L) poses a major health threat for the risk of CHDs, which can monitor fetal CHDs at-risk pregnancies.