Maternal multivitamin supplementation mitigates the risk of fetal congenital heart disease associated with high indoor total volatile organic compounds exposure in east china: a case-control study

Background: Congenital heart disease (CHD) is a common birth defect. Our previous studies suggest that indoor air pollution, especially total volatile organic compounds (TVOCs), may increase fetal CHD risk, whereas vitamin and folic acid (FA) supplements in early pregnancy might offer protection against CHD. However, limited research has explored whether FA or multivitamin supplementation can mitigate the effects of TVOCs exposure on CHD.

Methods: We conducted a case-control study to investigate the association between maternal nutrient supplementation, household indoor air pollutant exposure during pregnancy, and CHD in offspring. Pregnant women with 22-30 gestational weeks were recruited from two hospitals in East China between January 2016 and March 2022. A comprehensive approach was used, incorporating questionnaires to collect nutrient supplement information, blood sample analysis to detect serum folate, vitamin B12, and homocysteine (HCY) concentrations, and field investigations to assess indoor benzene, toluene, xylene, formaldehyde, and TVOCs exposures. Logistic regression analysis was performed to identify CHD risk factors, and stratified analysis was used to evaluate the combined effects of nutrient supplementation and TVOCs on CHD.

Results: The study included 53 cases and 77 controls. Logistic regression analysis identified high maternal serum HCY (> 6.125 µmol/L) and high household TVOCs exposure (> 0.0165 mg/m³) as risk factors for CHD in offspring, with adjusted odds ratios of 2.98 (95% CI: 1.31-6.36) and 9.23 (95% CI: 3.78-22.53), respectively. Regular multivitamin supplementation mitigated the risk of high TVOCs exposure on fetal CHD, while the adverse effect of high serum HCY-related CHD risk was attenuated in the group with regular FA supplementation.

Conclusion: Exposure to high indoor TVOCs concentrations increases the risk of fetal CHD. Regular multivitamin supplementation may reduce the adverse effects of high TVOCs exposure on fetal CHD.