Tobacco Use in Children Affects Cognitive Function and Brain Structure Long-Term

Children who first used tobacco products during their late childhood demonstrated worse cognitive performance and reduced brain structure, which were sustained long-term, according to study findings published in JAMA Network Open.

Researchers conducted a longitudinal, observational, cohort study in 2 waves — wave 1 between October 1, 2016 and October 31, 2018, and wave 2 between August 1, 2018 and January 31, 2021. They obtained data of children aged 9 to 10 years from the Adolescent Brain Cognitive Development (ABCD) study across 21 cities in the United States. After excluding missing data, poor imaging results, and medical reasons that might have influenced the results of this study, 10,214 children participated in wave 1 (mean age 9.9 years; SE, 0.6; 47.9% girls and 52.1% boys; 20.3% Hispanic; 14.9% non-Hispanic Black; and 52.1% non-Hispanic White) of the ABCD study and 6859 children participated in the 2-year follow-up (wave 2).

All children underwent the National Institutes of Health (NIH) Cognition Battery as well as magnetic resonance imaging (MRI) to measure cognitive functioning and cortical surface area, volume, and subcortical segmentation, respectively.  

The children who self-reported tobacco use on questionnaires were classified as “ever users of tobacco”. Approximately 116 children used tobacco products during their childhood with 80 smoking e-cigarettes, 12 using smokeless tobacco products, 10 smoking cigars, 7 smoking hookah, 8 using nicotine replacement products, and 5 smoking pipes. Boys and those who used other substances were more likely to use tobacco products.

Wave 1 children who used tobacco products demonstrated worse scores in crystallized cognition (b = –2.4; SE, 0.5; P <.001), total cognition (b = –2.9; SE, 0.5; P =.01), and the Picture Vocabulary Test (mean, b = –2.9; SE, 0.6; P <.001). At the 2-year follow-up, tobacco users during late childhood continued exhibiting worse higher-order cognitive functions, including oral reading recognition (b = –2.1; SE, 0.5; P <.001), the Picture Vocabulary Test (b = –3.0; SE, 0.7; P <.001), Picture Sequence Memory (b = –3.0; SE, 0.7; P =.007), and crystallized cognition composite scores (b = –2.7; SE, 0.8; P =.005) compared with nonusers.

Wave 1 tobacco users demonstrated decreased total cortical surface area (b = −5014.8 mm²; SE, 1739.8; P =.004) and total cortical volume (b = –174,621.0 mm³; SE, 5857.7 mm³; P =.003). At the 2-year follow-up, they continued to show decreased total cortical volume (b = –21,790.8 mm³; SE, 7043.9; P =.002), and intracranial volume (b = –38,442.8 mm³; SE, 12,057.7; P =.009).

In wave 2, regions of the brain affected by lower cortical volumes in tobacco users included the frontal, parietal, and temporal lobes.

“These findings suggest that youths vulnerable to e-cigarettes and tobacco products should be treated as a priority population in tobacco prevention,” the researchers stated.

They concluded, “Electronic cigarettes and smokeless tobacco products should not be treated as harm reduction alternatives for youth.”

Study limitations include the lack of full national representation within the ABCD study which did not study as many rural families, the inability to establish causal inference based on the observational nature of the study, the focus only on specific cortical morphometric measures, and the possibility of social desirability bias when the children self-reported tobacco use.