Developmental Correlates of Accelerated Molar Eruption in Early Childhood

Adversity has been linked to accelerated maturation. Molar eruption is a simple and scalable way to identify early maturation, but its developmental correlates remain unexplored. Thus, we examined whether accelerated maturation as indexed by molar eruption is associated with children's mental health or cognitive skills.

Molar eruption was evaluated from T2-weighted magnetic resonance imaging in 117 children (63 female; ages 4-7 years). Parents reported on child mental health with the Child Behavior Checklist. Children completed standardized assessments of fluid reasoning, working memory, processing speed, crystallized knowledge, and math performance. Relationships between molar eruption and developmental outcomes were examined using linear models, with age, gender, and stress risk as covariates.

Earlier molar eruption was positively associated with children's externalizing symptoms (false discovery rate-corrected p [p_FDR] = .027) but not internalizing symptoms, and the relationship with externalizing symptoms did not hold when controlling for stress risk. Earlier molar eruption was negatively associated with fluid reasoning (p_FDR < .001), working memory (p_FDR = .033), and crystallized knowledge (p_FDR = .001). The association between molar eruption and both reasoning and crystallized knowledge held when controlling for stress risk. Molar eruption also partially mediated associations between stress risk and both reasoning (proportion mediated = 0.273, p = .004) and crystallized knowledge (proportion mediated = 0.126, p = .016).

Accelerated maturation, as reflected in early molar eruption, may have consequences for cognitive development, perhaps because it constrains brain plasticity. Knowing the pace of a child's maturation may provide insight into the impact of a child's stress history on their cognitive development.