title: Comparative analysis of zinc protoporphyrin and blood lead levels in lead-exposed Andean children.
abstract: OBJECTIVE
  The objective of this study was to investigate the zinc protoporphyrin/heme ratio (ZPP/heme) as a biomarker for chronic lead (Pb) poisoning in children with a history of high Pb exposure.
  
  
  METHODS
  ZPP/heme ratio was measured in blood samples from 78 children (44 females and 34 males) with persistent Pb exposure from Pb glazing of ceramics in a local cottage industry in the Andes Mountains of Ecuador.
  
  
  RESULTS
  Mean blood lead (PbB) level was 26.4 microg/dL (SD: 23.2; range: 4.0-107.0), and the mean ZPP/heme ratio was 152.4 micromol/mol (SD: 190.6; range: 36.0-1064.0). A regression analysis of PbB level and ZPP/heme ratio revealed a significant association (r=0.761, p= <0.0001), with the logZPP showing a higher correlation with PbB (r=0.869, p= <0.0001). The ZZP/heme ratio decreased significantly with increasing age (ANOVA, p=0.030). The mean ZPP/heme ratios for females and males were 139.6 and 169.0 micromol/mol, respectively, and were not statistically different (t-test, p=0.504).
  
  
  CONCLUSIONS
  The elevated ZPP/heme ratios, coupled with high PbB levels observed in this cohort of Andean children of Pb-glazing workers, suggest chronic Pb intoxication and probable iron deficiency.
authors.affiliation: Department of Neurology, Harvard Medical School/The Biological Laboratories, Cambridge, MA 02138, USA. allen_counter@harvard.edu
authors.forename: S Allen
authors.initials: SA
authors.lastname: Counter
authors.forename: Leo H
authors.initials: LH
authors.lastname: Buchanan
authors.forename: Fernando
authors.initials: F
authors.lastname: Ortega
authors.forename: Nader
authors.initials: N
authors.lastname: Rifai
authors.forename: Michael W
authors.initials: MW
authors.lastname: Shannon
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D004484:Ecuador / Q000453:epidemiology; D005260:Female; D006418:Heme / Q000378:metabolism; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood*; D007855:Lead Poisoning / Q000097:blood* / Q000453:epidemiology; D008297:Male; D011524:Protoporphyrins / Q000097:blood*
chemical_list: D011524:Protoporphyrins; C017803:zinc protoporphyrin; D007854:Lead; D006418:Heme