Prenatal Tobacco Exposure, Brain Subcortical Volumes, and Gray-White Matter Contrast

Importance Maternal tobacco use during pregnancy (MTDP) remains a major public health challenge. However, the complete spectrum of effects of MTDP is not fully understood. Objectives To examine the longitudinal associations of MTDP and children's brain morphometric subcortical volume and gray-white matter contrast (GWC) development. Design, Setting, and Participants Cohort study of children aged 9 to 10 years at wave 1 (October 2016 to October 2018) and at a 2-year follow-up (wave 2; August 2018 to January 2021; aged 11-12 years) across 21 US sites in the Adolescent Brain Cognitive Development (ABCD) Study. Data were analyzed from October 2023 to October 2024. Exposure MTDP. Main outcomes and measures Morphometric brain measures of subcortical volume and GWC. Results Among the 11 448 children (51.5% male; 13.1% Black; 24.0% Hispanic; and 52.9% White) at wave 1, 1607 (16.6%; 95% CI, 13.0%-20.2%) were identified with MTDP exposure. At wave 1, children with MTDP exposure (vs no exposure) exhibited lower GWC in widespread brain regions primarily located in the frontal (eg, superior frontal; regression coefficient [B] = -0.0019; SE, 0.0006; P = .004), parietal (eg, supramarginal; B = -0.0021; SE, 0.0007; P = .002) and temporal lobes (eg, middle temporal; B = -0.0024; SE, 0.0007; P < .001). These differences in GWC continued to be significant at wave 2. In regard to subcortical volume, children with MTDP exposure demonstrated smaller volume of the lateral ventricle (B = -257.5; SE, 78.6; P = .001) and caudate (B = -37.7; SE, 14.0; P = .01) in the left hemisphere at wave 1, and lower volume of the caudate in both left (B = -48.7; SE, 15.9; P = .002) and right hemisphere (B = -45.5; SE, 16.1; P = .01) at wave 2. Conclusions and Relevance This cohort study found that MTDP exposure was associated with lower GWC across the whole cortex and smaller caudate nuclei volume compared with no exposure, signifying the importance of preventing MTDP and necessitating further research on this topic.