Oral or Poster Presentation
Concurrent Session 1A - Perinatal Epidemiology
Introduction: Previous studies have suggested an association between acetaminophen use during pregnancy and the development of attention deficit hyperactivity disorder (ADHD) in the offspring. These findings may be due to bias. Our primary objective was to assess the role of potential unmeasured confounding in the estimation of the association between acetaminophen use during pregnancy and the risk of ADHD in the offspring through bias analysis. Our secondary objective was to assess the roles of selection bias and exposure misclassification in the estimation of this association
Methods: We conducted a systematic literature search and meta-analyzed data across studies, using random-effects model. We conducted a bias analysis to studies that did not adjust for important confounders, to explore systematic errors related to unmeasured confounding, selection bias, and exposure misclassification.
Results: The systematic search resulted in seven studies included in our meta-analysis. When adjusted estimates were pooled across all studies, the risk ratio (RR) for ADHD was 1.35 (95% CI 1.25, 1.46, I2=48%). Sensitivity analysis for unmeasured confounding in this meta-analysis showed that a confounder of 1.69 with the exposure and outcome on the RR scale would reduce to 10% the proportion of studies with a true effect size of RR>1.10. Unmeasured confounding bias analysis decreased the point estimate in five of the seven studies and increased in two studies, suggesting that the observed association could be confounded by parental ADHD. Unadjusted and bias corrected risk ratios (bcRRs) were: RR=1.34, bcRR=1.13; RR= 1.51, bcRR=1.17; RR=1.63, bcRR=1.38; RR=1.44, bcRR=1.17, RR=1.16, bcRR=1.18, RR=1.25, bcRR=1.05 and RR=0.99, bcRR=1.18.
Conclusion: Bias analysis suggests that the previously-reported association between acetaminophen use during pregnancy and an increased risk of ADHD in the offspring may be due to unmeasured confounding. Our ability to conclude a causal association between acetaminophen use during pregnancy and childhood ADHD is limited.