BACKGROUND: Two prior population-based (children born in Olmsted County, MN), retrospective cohort studies both found that multiple exposures to anesthesia before age 3 were associated with a significant increase in the frequency of attention-deficit hyperactivity disorder (ADHD) and learning disabilities (LD) later in life. The primary purpose of this secondary analysis of these data was to test the hypothesis that a single exposure to anesthesia before age 3 was associated with an increased risk of ADHD. We also examined the association of single exposures with LD and the need for individualized educational plans as secondary outcomes. METHODS: This analysis includes 5339 children who were unexposed to general anesthesia before age 3 (4876 born from 1976 to 1982 and 463 born from 1996 to 2000), and 1054 children who had a single exposure to anesthesia before age 3 (481 born from 1976 to 1982 and 573 born from 1996 to 2000). The primary outcome of interest was ADHD. Secondary outcomes included LD (reading, mathematics, and written language) and the need for individualized educational programs (speech/language and emotion/behavior). To compare the incidence of each outcome between those who were unexposed and singly exposed to anesthesia before the age of 3 years, an inverse probability of treatment weighted proportional hazards model was used. RESULTS: For children not exposed to anesthesia, the estimated cumulative frequency (95% confidence interval [CI]) of ADHD at age 18 was 7.3% (95% CI, 6.5-8.1) and 13.0% (95% CI, 10.1-16.8) for the 1976-1982 and 1996-2000 cohorts, respectively. For children exposed to a single anesthetic before age 3, the cumulative frequency of ADHD was 8.1% (95% CI, 5.3-12.4) and 17.6% (95% CI, 14.0-21.9) for the 1976-1982 and 1996-2000 cohorts, respectively. In weighted analyses, single exposures were not significantly associated with an increased frequency of ADHD (hazard ratio [HR], 1.21; 95% CI, 0.91-1.60; P = .184). Single exposures were also not associated with an increased frequency of any LD (HR, 0.98; 95% CI, 0.78-1.23), or the need for individualized education plans. CONCLUSIONS: This analysis did not find evidence that single exposures to procedures requiring general anesthesia, before age 3, are associated with an increased risk of developing ADHD, LD, or the need for individualized educational plans in later life.
