According to a new study, researchers examined children with multiple exposures to anaesthesia before age three are more likely to develop adverse outcomes related to learning and attention. The study was published in Anesthesiology. They identified a cohort of children born between 1996 and 2000. Propensity matching selected children based on exposure or non-exposure to general anaesthesia before age 3. This identified 116 children multiply exposed, 457 singly exposed, and 463 unexposed children.

The researchers found that those with multiple, but not single exposures, had an increased frequency of both learning disabilities and attention-deficit/hyperactivity disorder (hazard ratio for learning disabilities, 2.17) versus unexposed children. Further, multiple exposures were associated with decreases in both cognitive ability and academic achievement. There was a modest association between single exposures and decreases in reading and language achievement but not cognitive ability.

Exposure of young animals to general anaesthesia causes neurodegeneration and lasting behavioural abnormalities; whether these findings translate to children remains unclear. This study used a population-based birth cohort to test the hypothesis that multiple, but not single, exposures to procedures requiring general anaesthesia before age three yr are associated with adverse neurodevelopmental outcomes.

These findings in children anaesthetized with modern techniques largely confirm those found in an older birth cohort and provide additional evidence that children with multiple exposures are more likely to develop adverse outcomes related to learning and attention. Although a robust association was observed, these data do not determine whether anaesthesia per se is causal.

A retrospective study cohort was assembled from children born in Olmsted County, Minnesota, from 1996 to 2000 (inclusive). Propensity matching selected children exposed and not exposed to general anaesthesia before age three yr. Outcomes ascertained via medical and school records included learning disabilities, attention-deficit/hyperactivity disorder, and group-administered ability and achievement tests. Analysis methods included proportional hazard regression models and mixed linear models.

"These findings in children anaesthetized with modern techniques largely confirm those found in an older birth cohort and provide additional evidence that children with multiple exposures are more likely to develop adverse outcomes related to learning and attention," the authors write. "Although a robust association was observed, these data do not determine whether anaesthesia per se is causal."