What proportion of the brain structural and functional abnormalities observed among children with fetal alcohol spectrum disorder is explained by their prenatal alcohol exposure and their other prenatal and postnatal risks?

BACKGROUND: Individuals with prenatal alcohol exposure (PAE) often present with a myriad of other prenatal (e.g. exposure to tobacco and other illicit drugs, poor prenatal care) and postnatal risk factors (e.g. multiple home placements, physical/sexual abuse, low socio-economic status)-all of which are likely contributing to their adverse outcomes. METHODS: A comprehensive neuropsychological battery, coupled with magnetic resonance imaging, was administered to children with fetal alcohol spectrum disorders (FASD) in 2009. Study participants diagnosed with FASD by the University of Washington using the FASD 4-Digit Code were compared to typically-developing peers with no PAE. Data from this MRI study were used to explore the proportion of variance in brain structural and functional abnormalities explained by PAE and 14 other prenatal and postnatal risk factors. RESULTS: PAE was the dominant risk factor explaining the largest proportion of variance in regional brain size (total brain, frontal lobe, caudate, hippocampus and corpus callosum) and brain function (intellect, achievement, memory, language, executive-function, motor, adaptation, behavior-attention and mental health symptoms). Other prenatal and postnatal risk factors were 3 to 7-fold more prevalent than in the general population. Individually, each risk factor explained a statistically significant, but smaller proportion of variance in brain outcome compared to PAE. In combination, the proportion of variance explained by the presence of multiple prenatal and postnatal risks rivaled that of PAE. CONCLUSION: A better understanding of the impact other prenatal and postnatal risk factors have on the neurodevelopmental outcomes of individuals with FASD can inform more effective prevention and intervention strategies.