Prenatal Exposure to Tobacco and Childhood Cognition and Behavior: Effect Modification by Maternal Folate Intake and Breastfeeding Duration

In this exploratory analysis, we assessed whether nutrition modified the association between prenatal exposure to tobacco and childhood cognition/behavior among 366 Colorado-based mothers and their offspring (born ≥ 37 weeks with birthweights ≥ 2500 g). Interaction by folate (≥ 1074 µg/day) and breastfeeding (≥ 5 months) was assessed by including a product term with cotinine (≥ limit of detection [LOD]) in regression models for NIH Toolbox and Child Behavior Checklist T-scores. Main effects were observed between cotinine ≥ LOD and inhibitory control (− 3.2; 95% CI: − 6.8, 0.3), folate < 1074 µg/day and anxious/depressed symptoms (1.1; 95% CI: 0.1, 2.1), and breastfeeding < 5 months and receptive language (− 4.3; 95% CI: − 8.5, − 0.02), though these findings would not survive Bonferroni correction. Breastfeeding modified the tobacco-behavior associations. Sleep (3.8; 95% CI: 0.5, 7.1; interaction p-value = 0.02), depressive (4.6; 95% CI: 1.0, 8.2; interaction p-value = 0.01) and total problems (5.8; 95% CI: − 0.7, 12.4; interaction p-value = 0.09) were observed among tobacco-exposed offspring who breastfed > 5 months, but not for shorter durations. Our findings support the need for smoking cessation campaigns throughout pregnancy and throughout the postpartum period breastfeeding to reduce neurobehavioral risks in the offspring.