Associations Were Significant for Boys and Girls Weighing More than 5.5 lbs at Birth
Researchers from Taiwan found a correlation between neonatal jaundice and the development of autism spectrum disorder (ASD) or attention deficit hyperactivity disorder (ADHD) in children. The authors report that this link persisted even after controlling for confounding factors. Neonatal or infant jaundice is the yellow discoloration of a newborn baby’s skin and eyes. The condition occurs due to an excess of bilirubin, a yellowish pigment found in bile, a fluid made by the liver. The current study showed that the association between jaundice, ASD and ADHD existed in infants of both sexes with birth weights larger than 2500 grams (5.5 lbs). The adjusted hazard ratios of ASD and ADHD were higher for newborns with jaundice, and the magnitude of these associations was similar to previous research. The authors propose that unbound bilirubin deposits in the hippocampus can affect neurogenesis (i.e., the process by which neurons form in the brain) and synaptic function in neural development. When these two processes are impaired, long-term synaptic plasticity in the hippocampus is affected, resulting in a decreased density of dendritic spines and synapses. The researchers suggest that this mechanism is the anatomical and molecular basis that could explain the association between excess bilirubin and the risk of developing ASD or ADHD in childhood
