Prenatal exposure to perfluorinated chemicals and attention deficit/hyperactivity symptoms in children at 7 years of age

Abstract

Background: Perfluorinated compounds (PFCs), persistent pollutions in environment, can cross the placental barrier and enter fetal circulation. Animal studies report exposure to the PFCs can give irreversible change in mouse brain and affect development. The association between perfluorooctanoic acid (PFOA) and perfluorooctylsulfonate (PFOS) exposure and ADHD symptoms is controversial in epidemiological studies. Aims: We evaluated the association between prenatal exposures to PFCs and ADHD symptoms. Methods: A total of 282 mother–newborn pairs from various medical facilities recruited from May 2004 to July 2005. Cord blood samples were collected at birth and analyzed for PFOA, PFOS, perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUA) by ultra-high performance liquid chromatography/tandem mass spectrometry. We assessed children behavioral health by using the Chinese version of the Swanson, Nolan, and Pelham, version IV scale (SNAP-IV), the Strengths and Difficulties Questionnaire (SDQ), and the Child Behavior Checklist (CBCL). Multiple linear and logistic regression models were used to examine the relationship between nature log transformed PFCs concentrations and scales. Results: The median concentrations of PFOA, PFOS, PFNA and PFUA were 0.8, 3.7, 1.3 and 2.9 ng/mL, respectively. After adjusting for potential confounding factors, we found increased PFNA concentrations were inversely associated with peer problems [odds ratio (OR) = 0.73; 95% confidence interval (CI), 0.57–0.92] and hyperactivity/impulsivity (OR=0.68; 95% CI, 0.54–0.88) and oppositional defiant disorder (OR = 0.71; 95% CI, 0.55–0.90). Increased PFUA concentrations also had inverse associations with peer problems (OR = 0.56; 95% CI, 0.42–0.74). Conclusions: Our findings suggest PFOA and PFOS are not associated with behavioral problems in childhood. However, PFNA and PFUA are negatively associated with some scales of SDQ and SNAP. Mechanistic studies are needed to elucidate the relationship between PFCs and ADHD.