title: Blood lead concentrations and attention deficit hyperactivity disorder in Korean children: a hospital-based case control study.
abstract: BACKGROUND
  Because the developing brain of a child is vulnerable to environmental toxins, even very low concentration of neurotoxin can affect children's neurodevelopment. Lead is a neurotoxic heavy metal which has the harmful effect on the striatal-frontal circuit of brain. This area of the brain is known to be closely related to attention deficit hyperactivity disorder (ADHD) pathophysiology. The primary objective of the present study was to investigate whether elevated blood lead concentration is a risk factor for ADHD. The secondary objective was to examine the association between blood lead concentration and symptom severity.
  
  
  METHODS
  We conducted a frequency-matched, hospital-based case-control study with 114 medically diagnosed ADHD cases and 114 controls. The participants were matched for age and sex. The diagnoses of ADHD were assessed with semi-structured diagnostic interviews. The participants completed the continuous performance test (CPT), and their parents completed the ADHD-rating scale (ADHD-RS). Blood lead concentrations were measured by using graphite furnace atomic absorption spectrometry featuring Zeeman background correction.
  
  
  RESULTS
  Children with ADHD exhibited blood lead concentrations that were significantly higher than those of the controls ( 1.90 ± 086 μg/dℓ vs. 1.59 ± 0.68 μg/dℓ, p = 0.003). The log transformed total blood lead concentration was associated with a higher risk of ADHD (OR: 1.60, 95 % CI: 1.04-2.45, p < 0.05). The analysis also revealed that the children with blood lead concentrations above 2.30 μg/dℓ were at a 2.5-fold (95 % CI: 1.09-5.87, p < 0.05) greater risk of having ADHD. After adjusting for covariates, our multivariate regression models indicated that blood lead concentrations were not significantly associated with ADHD-RS or CPT profiles among the ADHD cases.
  
  
  CONCLUSIONS
  Even low blood lead concentrations are a risk factor for ADHD in children. This study warrants primary prevention policies to reduce the environmental lead burden. Future studies may be required to ascertain the effects of lead on symptom severity in ADHD.
authors.affiliation: Department of Psychiatry, College of Medicine, Dong-A University, Dong-A University Hospital, 26 Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea.
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Park
authors.affiliation: Heavy Metal Exposure Environmental Health Center, Dong-A University, 32, Daesingongwon-ro, Seo-gu, Busan, 602-714, Republic of Korea.
authors.forename: Ju-Hee
authors.initials: JH
authors.lastname: Seo
authors.affiliation: Heavy Metal Exposure Environmental Health Center, Dong-A University, 32, Daesingongwon-ro, Seo-gu, Busan, 602-714, Republic of Korea.|Department of Preventive Medicine, College of Medicine, Dong-A University, Dong-A University Hospital, 26, Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea.
authors.forename: Young-Seoub
authors.initials: YS
authors.lastname: Hong
authors.affiliation: Heavy Metal Exposure Environmental Health Center, Dong-A University, 32, Daesingongwon-ro, Seo-gu, Busan, 602-714, Republic of Korea.|Department of Preventive Medicine, College of Medicine, Dong-A University, Dong-A University Hospital, 26, Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea.
authors.forename: Yu-Mi
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Department of Child and Adolescent Psychiatry, College of Medicine, Inje University Busan Paik Hospital, 75 Bokji-ro, Busanjin-gu, Busan, 614-735, Republic of Korea.
authors.forename: Je-Wook
authors.initials: JW
authors.lastname: Kang
authors.affiliation: Department of Pediatrics, College of Medicine, Dong-A University, Dong-A University Hospital, 26 Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Yoo
authors.affiliation: Department of Pediatrics, College of Medicine, Dong-A University, Dong-A University Hospital, 26 Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea.
authors.forename: Hee Won
authors.initials: HW
authors.lastname: Chueh
authors.affiliation: Department of Pediatrics, Kosin University Gospel Hospital, 262, Gamcheon-ro, Seo-gu, Busan, 602-702, Republic of Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, 179, Gudeok-ro, Seo-gu, Busan, 602-739, Republic of Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kwak
authors.affiliation: Molecular Epidemiology Branch, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 410-769, Republic of Korea.
authors.forename: Jeongseon
authors.initials: J
authors.lastname: Kim
authors.affiliation: Molecular Epidemiology Branch, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 410-769, Republic of Korea.
authors.forename: Hae Dong
authors.initials: HD
authors.lastname: Woo
authors.affiliation: Department of Home Economics, College of Natural Science, Korea National Open University, 86, Daehak-ro, Jongno-gu, Seoul, 110-791, Republic of Korea.
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, College of Medicine, Dong-A University, Dong-A University Hospital, 26 Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea.
authors.forename: Young Rong
authors.initials: YR
authors.lastname: Bang
authors.affiliation: Department of Psychiatry, College of Medicine, Dong-A University, Dong-A University Hospital, 26 Daesingongwon-ro, Seo-gu, Busan, 602-715, Republic of Korea. bmchoe@dau.ac.kr.
authors.forename: Byeong Moo
authors.initials: BM
authors.lastname: Choe
keywords: ADHD; Child; Environment; Heavy Metal; Lead