Agonizing over Beta 2 Agonists and Autism

Background Recent reports indicate a high prevalence of autism with 1 in 68 children meeting the criteria for autism spectrum disorders (ASD).1 ASD is reported to occur in all racial, ethnic, and socioeconomic groups.1 ASD is approximately 4.5 times more common among boys (1 in 42) than girls (1 in 189).1 The etiologies for ASD are heterogeneous; genetic factors play a major role in many patients.2 The role of environmental factors has been a key area for research.3In utero exposure with drugs such as valproate and thalidomide has been linked to ASD.4,5 One epidemiological study in 2011 reported a possible role of in utero exposure of beta-2 adrenergic receptor (B2AR) agonists in causation of ASD.6 In this study, Croen et al6 reported that ASD was 4 times more likely in those with IV terbutaline exposure during third trimester but did not find a significant risk with other B2AR agonists. When assessing the hazard risk, they used conditional logistic regression analysis and adjusted the risk for gender, parental age, and maternal diagnosis of asthma.