Supplementary material from "Typical self-regulation and white matter brain fibre properties in preterm adolescents from the ABCD cohort"

Preterm birth is associated with impairments in self-regulation and altered white matter fibre properties of brain areas linked to self-regulation in childhood, which may extend into adolescence. As self-regulation can be effectively targeted by interventions, it is important to understand such potential disadvantages and their neural sources in vulnerable groups. We examined associations between gestational age (GA) at birth, white-matter fibre properties (e.g., fractional anisotropy, FA), and self-regulation, as well as brain–behaviour associations at the onset of adolescence. We hypothesised that lower GA relates to poorer self-regulation ability and reduced FA in brain fibres connecting self-regulation hubs, and that self-regulation correlates positively with FA. Participants were drawn from the Adolescent Brain Cognitive Development (ABCD) study: 1,695 preterm and 1,693 term-born adolescents for behavioural analyses, and 1,304 preterm and 1,379 term-born adolescents for neural analyses. Associations between GA, self-regulation, and fibre properties were tested using local structural equation modelling (SEM) and brain–behaviour associations were estimated via regularised SEM. None of the hypotheses were supported by the data. We suspect a sampling bias in the ABCD preterm cohort towards better adapted individuals, highlighting the importance of considering cohort characteristics when generalising results from this cohort to the broader preterm population.