Socioeconomic status and economic hardship attenuated the associations between early tobacco or nicotine use and brain outcomes in preadolescent children.

OBJECTIVES

Early tobacco use (before age 11) is linked to poorer cognition and reduced cortical surface area and volume in young adolescents. This study examined how socioeconomic status (SES) factors - parental education, household income, and economic hardships - influenced these associations.

METHODS

Using baseline (N=11,876) and year 3 (N=10,414) datasets from the Adolescent Brain Cognitive Development study, we assessed the impact of baseline tobacco/nicotine use initiation on cognitive scores, cortical volume, thickness, and surface area across the entire cohort and in propensity-matched subgroups. Linear mixed effects models controlled for SES and other covariates, with multiple comparison correction. Analyses were cross-sectional at baseline and longitudinal with both timepoints.

RESULTS

Compared to non-users (N=11,240), early users (N=110) had more advanced pubertal development (p=0.003) and economic hardships (p<0.001), but fewer girls (p=0.04), Hispanics (p=0.02), parents with graduate degrees (p<0.001) and high-income families >$100 K (p=p<0.001). Relative to non-users, early users had poorer cognitive scores (Cohen's d: -0.69 to -0.24), smaller surface areas (Cohen's d: -2.28 to -0.22), similar cortical thickness at both timepoints, and by year 3, smaller cortical volumes (Cohen's d: -1.06 to -1.24). However, SES-adjustments eliminated cognitive scores and volumes differences and reduced cortical surface area effects at both timepoints (Cohen's d: -1.92 to -0.51). After propensity score matching, early users and non-users showed no cognitive or brain differences, regardless of SES adjustments.

CONCLUSIONS

Adjusting for SES eliminated the negative impact of early tobacco/nicotine use on cognition and reduced its effect on brain surface area, underscoring the importance of SES in morphometry studies.