(P27-056-25) The Association of Radon Exposure With Preterm Birth Modified by B Vitamin Intakes: Findings From the nuMoM2b Study

Objectives: While radon exposure has been linked to some pregnancy outcomes, e.g., gestational diabetes and hypertensive disorder, little is known about radon and preterm birth. Also, studies have indicated that B vitamins (folate, B₆, B₁₂) may modify radon impact because of their properties of anti-oxidative stress and DNA repair. We prospectively examined the association of radon exposure with preterm birth and determined whether preconception intake of B vitamins modifies the association of interest.

Methods: Participants (n=9336) from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be (nuMoM2b) with available data were included. County-level radon concentrations, derived from the Lawrence Berkeley National Laboratory, were linked to participant’s residential address for each visit. Preterm birth was defined as live birth before 37 weeks of gestation. At baseline (6⁰ to 13⁶ weeks’ gestation), dietary information for the three months prior to pregnancy, including B vitamin intakes from both diet and supplement, was assessed by using the modified Block 2005 Food Frequency Questionnaire. A multivariable logistic regression model was performed to estimate the odds ratio of preterm birth by radon exposure.

Results: The median radon exposure was 1.31 pCi/L (interquartile range: 0.90-2.72). After controlling for potential confounders, the association of radon exposure with preterm birth was marginally significant (odds ratio [OR] and 95% confidence interval [CI] for quintile 5 (highest) vs. quintile 1 (lowest): 1.25, 0.91-1.70, P_trend=0.07). The association of interest was stronger and became significant among individuals with low B vitamin intakes (< median). The ORs (95% CIs) were 1.66 (1.01-2.74), P_trend=0.03 for folate; 1.63 (1.001-2.67), P_trend=0.01 for vitamin B₆ and 1.52 (0.93-2.49), P_trend=0.03 for vitamin B₁₂ respectively, but non-significant among those with high B vitamin intakes ( >= median). Nevertheless, the tests for interactions between radon and B vitamins were statistically non-significant.

Conclusions: Findings from this large cohort study indicate that the association of radon exposure with preterm birth may be modified by B vitamin intakes. Pregnant people with higher radon exposure and lower B vitamin intake may be more likely to give preterm birth.

Funding Sources: Faculty start-up funds from Ball States University