Investigators from the University of Calgary, Calgary, Canada, conducted a retrospective study to assess the association between low levels of prenatal alcohol exposure (PAE) and brain structure and function. For the study, they analyzed data collected as part of the Adolescent Brain Cognitive Development (ABCD) Study, in which structural MRI, resting-state functional MRI, and diffusion tensor imaging were obtained on >10,000 US children who were approximately 10 years old. Cases for the current study were children whose biologic mothers indicated that they used alcohol after awareness of their pregnancy, and denied use of other substances, including tobacco, cannabis, heroin, cocaine, and oxycodone. Alcohol consumption was quantified based on answers to, “average drinks per week?” and “maximum drinks in 1 sitting?” after knowing of pregnancy. Controls were children whose biologic mothers denied use of alcohol or other substances after awareness of pregnancy, and were matched to cases on sex, age, maternal education level, and family income. Data abstracted from neuroimaging results in study participants included fractional anisotropy (FA), a measure of connectivity in the brain, from multiple white matter regions, cortical brain volume, and total intracranial volume. Participants in the ABCD study also completed the Child Behavior Checklist (CBCL); scores on the internalizing and externalizing behaviors scales were abstracted for the current analysis. Neuroimaging imaging and CBCL scores in cases and controls were compared using multiple statistical tests, with results corrected for false discovery rate because of multiple comparisons.
Data were analyzed on 135 cases and 135 controls with mean ages of 9.85 ±0.65 and 9.87 ±0.04 years, respectively. The mean number of drinks per week reportedly consumed during pregnancy by mothers of case children was 1 ±1, and mean maximum number of drinks consumed at 1 sitting was 1 ±1. FA was significantly lower in those with PAE than in control children in 5 white matter regions: left postcentral, left inferior parietal, left planum temporal, left inferior occipital, and right middle occipital. Children in the PAE group had significantly higher total cortical brain volume than unexposed controls, but there was no significant difference between groups for total intracranial volume. Most participants had normal scores on CBCL scales (defined as <65), but scores for externalizing behaviors were significantly higher (ie, worse) in cases than controls (mean scores, 45.2 ±9.0 and 42.8 ±9.0, respectively; mean difference, 2.39; 95% CI, 0.30, 4.47). Two children in the PAE group and 0 controls had scores ≥65. There were no differences between groups for internalizing behavior scores.
The authors conclude that children with low levels of PAE had lower FA and more behavioral problems than well matched unexposed controls.
Dr Badawi has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.