title: Childhood blood lead levels and intellectual development after ban of leaded gasoline in Taiwan: a 9-year prospective study.
abstract: BACKGROUND
  Lead (Pb) exposure is associated with children's neurodevelopment, even at low doses. Leaded gasoline was banned in Taiwan in 2000 to reduce environmental exposure to Pb.
  
  
  OBJECTIVE
  To evaluate the neurodevelopmental effect of low-level Pb exposure in young children.
  
  
  METHODS
  In 2001-2002, we have recruited 430 pregnant women in the third-trimester in Taichung, Taiwan who answered detailed questionnaires in the obstetric clinic. A total of 119, 76, and 66 children were followed up at 2-3, 5-6 and 8-9 years, respectively. We collected blood samples from pregnant women, Umbilical cord and children, and evaluated children's neurodevelopment and cognition function at all three time points using Bayley and Wechsler tests. Blood samples were analyzed for whole blood lead (BPb) levels.
  
  
  RESULTS
  Geometric mean of BPb in pregnant women, cord blood and children at 2-3, 5-6 and 8-9 years old were 2.21, 1.30, 2.48, 2.49 and 1.97 μg/dl, respectively. Low-level postnatal Ln BPb was significantly associated with not only decreasing intelligence quotient (IQ), but also delayed cognitive function in children at 5-8 years (β: -5.97, SE: 2.59, p=0.025), after adjustment for maternal education, maternal BPb exposure, Home Observation for Measurement of the Environment Inventory (HOME), and gender of child, using linear mixed models. No significant relation was observed between prenatal and cord blood Pb levels and children's cognitive function in children 2-8 years.
  
  
  CONCLUSIONS
  Low-level postnatal BPb levels in children at 2-5 years may have lagged effects on neurodevelopment in those at 5 to 8 years. Action is warranted to reduce even very low environmental Pb levels to reduce the developmental burden of Pb on children.
authors.affiliation: Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan.
authors.forename: Po-Chin
authors.initials: PC
authors.lastname: Huang
authors.affiliation: Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan; School of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Pen-Hua
authors.initials: PH
authors.lastname: Su
authors.affiliation: Department of Special Education, National Taiwan Normal University, Taipei, Taiwan.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Chen
authors.affiliation: Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan; Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Han-Bin
authors.initials: HB
authors.lastname: Huang
authors.affiliation: Graduate Institute of Occupational Safety and Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Jin-Lian
authors.initials: JL
authors.lastname: Tsai
authors.affiliation: Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan.
authors.forename: Hsin-I
authors.initials: HI
authors.lastname: Huang
authors.affiliation: Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan; Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan. Electronic address: slwang@nhri.org.tw.
authors.forename: Shu-Li
authors.initials: SL
authors.lastname: Wang
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000097:blood*; D000397:Air Pollution / Q000331:legislation & jurisprudence*; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005742:Gasoline; D006801:Humans; D007360:Intelligence; D007854:Lead / Q000097:blood*; D016014:Linear Models; D008297:Male; D018811:Maternal Exposure / Q000706:statistics & numerical data; D011247:Pregnancy; D011446:Prospective Studies; D013624:Taiwan; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D005742:Gasoline; D007854:Lead