Association between phthalates and externalizing behaviors and cortical thickness in children with attention deficit hyperactivity disorder.
BACKGROUND
Previous studies have implicated the relationship between environmental phthalate exposure and attention deficit hyperactivity disorder (ADHD) symptoms of childhood, but no studies have been conducted in children who have a confirmed diagnosis of ADHD obtained through meticulous diagnostic testing. We aimed to determine whether phthalate metabolites in urine would be higher in children with ADHD than in those without ADHD and would correlate with symptom severity and cortical thickness in ADHD children.


METHODS
A cross-sectional examination of urine phthalate metabolite concentrations was performed; scores for ADHD symptoms, externalizing problems, and continuous performance tests were obtained from 180 children with ADHD, and brain-imaging data were obtained from 115 participants. For the control group, children without ADHD (N = 438) were recruited. Correlations between phthalate metabolite concentrations and clinical measures and brain cortical thickness were investigated.


RESULTS
Concentrations of phthalate metabolites, particularly the di(2-ethylhexyl) phthalate (DEHP) metabolite, were significantly higher in boys with ADHD than in boys without ADHD. Concentrations of the di-n-butyl phthalate (DBP) metabolite were significantly higher in the combined or hyperactive-impulsive subtypes compared to the inattentive subtype, and the metabolite was positively correlated with the severity of externalizing symptoms. Concentrations of the DEHP metabolite were negatively correlated with cortical thickness in the right middle and superior temporal gyri.


CONCLUSIONS
The results of this study suggest an association between phthalate concentrations and both the diagnosis and symptom severity of ADHD. Imaging findings suggest a negative impact of phthalates on regional cortical maturation in children with ADHD.
Department of Child and Adolescent Psychiatry,Seoul National Hospital,Seoul,Republic of Korea.
S
S
Park
Department of Biomedical Engineering,Hanyang University,Seoul,Republic of Korea.
J-M
JM
Lee
Division of Child and Adolescent Psychiatry,Department of Psychiatry,Seoul National University Hospital,Seoul,Republic of Korea.
J-W
JW
Kim
Uimyung Research Institute for Neuroscience,Sahmyook University,Seoul,Republic of Korea.
J H
JH
Cheong
Department of Biomedical Engineering,Hanyang University,Seoul,Republic of Korea.
H J
HJ
Yun
Department of Preventive Medicine,Seoul National University College of MedicineandInstitute of Environmental Medicine,Seoul,Republic of Korea.
Y-C
YC
Hong
Department of Child and Adolescent Psychiatry,Seoul National Hospital,Seoul,Republic of Korea.
Y
Y
Kim
Department of Psychiatry,Chung Ang University,College of Medicine,Seoul,Republic of Korea.
D H
DH
Han
College of Medicine and Behavioral Medicine Institute,Seoul National University,Seoul,Republic of Korea.
H J
HJ
Yoo
Division of Child and Adolescent Psychiatry,Department of Psychiatry,Seoul National University Hospital,Seoul,Republic of Korea.
M-S
MS
Shin
Division of Child and Adolescent Psychiatry,Department of Psychiatry,Seoul National University Hospital,Seoul,Republic of Korea.
S-C
SC
Cho
Division of Child and Adolescent Psychiatry,Department of Psychiatry,Seoul National University Hospital,Seoul,Republic of Korea.
B-N
BN
Kim
D000293:Adolescent; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology* / Q000652:urine*; D002540:Cerebral Cortex / Q000473:pathology*; D002648:Child; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010795:Phthalic Acids / Q000652:urine*; D056910:Republic of Korea; D012720:Severity of Illness Index
D010795:Phthalic Acids
phthalate