Prenatal Exposure to Perfluorinated Chemicals, Attention-deficit/hyperactivity disorder and Autism

Introduction: Perfluorinated chemicals (PFCs) are persistent pollutants with widespread human exposure. Animal data suggest PFCs are endocrine disruptors and neurotoxic. Positive associations between PFCs and attention-deficit/hyperactivity disorder (ADHD) in children were reported in cross-sectional data, but findings from prospective studies are limited. We investigated whether prenatal exposure to PFCs increases the risks of developing ADHD or childhood autism in children.
Methods: We studied 83,389 liveborn singleton children and mothers enrolled in the Danish National Birth Cohort during 1996–2002. From a total of 890 ADHD cases and 301 autism cases identified from the Danish National Hospital Register and the Danish Psychiatric Central Registry in 2011, we randomly selected 220 cases of ADHD and autism each into a case-cohort study and also randomly selected 550 controls frequency matched on child’s sex. Fifteen PFCs were measured in maternal plasma samples from early or mid-pregnancy. We used unconditional logistic regressions to estimate odds ratios.
Results: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were detected in all samples, and 6 other PFCs were quantified in about half samples. We found no associations between ADHD or autism in children and maternal PFC concentrations (modeled as per inter-quartile range or natural log unit increase, as well as categorized in quartile). No effect measure modification by child’s sex.
Conclusions: We found no evidence to suggest prenatal PFC exposures increase the risks of ADHD or autism in children in the Danish birth cohort.