LAUSR

BACKGROUND The evidence for a relationship between general anaesthesia induced in childhood and the risk of attention-deficit hyperactivity disorder (ADHD) in later life is inconsistent. We systematically assessed whether such an association existed. METHODS We searched the PubMed and EMBASE databases for relevant cohort studies. Relative risks (RRs) and 95 % confidence intervals (CIs) were calculated to determine the relationship between induction of childhood general anaesthesia and the risk of ADHD in later life. RESULTS Seven studies (eight publications) on developmental outcomes after the induction of childhood general anaesthesia met our inclusion criteria but not our exclusion criteria. Repeat childhood general anaesthesia (RR = 1.84, 95 CI% 1.14-2.97; P < 0.001; I2 = 74.8 %), but not one-off general anaesthesia (RR = 1.09, 95 CI% 0.93-1.27; P = 0.301; I2 = 0%), was associated with an increased risk of ADHD in later life. The association was evident only when the total general anaesthesia exposure exceeded 90 min. CONCLUSIONS Our meta-analysis indicated that the effect of general anaesthesia on the risk of ADHD is dose- or duration-dependent.