Association between body mass index and subcortical volume in pre-adolescent children with autism spectrum disorder: An exploratory study.
Control for BMI in autism imaging studies because body fat shifts subcortical brain volumes in ways unique to these kids.
01Research in Context
What this study did
Hwang et al. (2022) scanned the brains of pre-teen children with and without autism. They measured how body weight related to the size of deep-brain structures.
The team wanted to know if extra body fat changes the brain differently in autism than in typical kids.
What they found
Kids with autism had smaller caudate nuclei on both sides of the brain. In both groups, higher body mass index changed the size of other deep structures.
The twist: the same BMI number altered brain volumes in opposite ways for autism versus typical kids. So weight must be tracked when reading MRI scans.
How this fits with other research
Kupis et al. (2021) saw the same BMI-by-diagnosis pattern, but for brain connectivity instead of size. Together the papers show body weight touches multiple brain measures in autism.
Li et al. (2022) also worked on subcortical volumes. They grouped kids to shrink scatter; In-Seong shows part of that scatter is BMI. The newer study adds a control step the older one missed.
Griffith et al. (2012) mapped cortical thickness in autism kids years ago. Their raw thickness data may now need re-checking with BMI added, because In-Seong proves weight can flip volume effects.
Why it matters
Before you label an MRI difference as "autism," record the child’s BMI and include it in your stats. A high number might explain odd volumes that looked like core autism traits. Share this note with the medical team so diet or activity plans can protect both brain and body health.
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02At a glance
03Original abstract
Conflicting associations exist between autism spectrum disorder (ASD) and subcortical brain volumes. This study assessed whether obesity might have a confounding influence on associations between ASD and brain subcortical volumes. A comprehensive investigation evaluating the relationship between ASD, obesity, and subcortical structure volumes was conducted. Data obtained included body mass index (BMI) and T1-weighted structural magnetic resonance images for children with and without ASD diagnoses from the Autism Brain Imaging Data Exchange database. Brain subcortical volumes were calculated using vol2Brain software. Hierarchical linear regression analyses were performed to explore the subcortical volumes similarly or differentially associated with BMI in children with or without ASD and examine association and interaction effects regarding ASD and subcortical volume impact on the Social Responsiveness Scale and Vineland Adaptive Behavior Scale (VABS) scores. Bilateral caudate nuclei were smaller in children with ASD than in control participants. Significant interactions were observed between ASD diagnosis and BMI regarding the left caudate, right and left putamen, and right and left ventral diencephalon (DC) volumes (β = -0.384, p = 0.010; β = -0.336, p = 0.030; β = -0.317, p = 0.040; β = 0.322, p = 0.010; β = 0.295, p = 0.021, respectively) and between ASD diagnosis and right and left ventral DC volumes regarding the VABS scores (β = 0.434, p = 0.014; β = 0.495, p = 0.007, respectively). However, each subcortical structure volume included in the ventral DC area could not be measured separately. The results identified subcortical volumes differentially associated with obesity in children with ASD compared with typically developing peers. BMI may need to be considered an important confounder in future research examining brain subcortical volumes within ASD.
Autism research : official journal of the International Society for Autism Research, 2022 · doi:10.1002/aur.2834