title: Use of a Cumulative Exposure Index to Estimate the Impact of Tap Water Lead Concentration on Blood Lead Levels in 1- to 5-Year-Old Children (Montréal, Canada).
abstract: BACKGROUND
  Drinking water is recognized as a source of lead (Pb) exposure. However, questions remain about the impact of chronic exposure to lead-contaminated water on internal dose.
  
  
  OBJECTIVE
  Our goal was to estimate the relation between a cumulative water Pb exposure index (CWLEI) and blood Pb levels (BPb) in children 1-5 years of ages.
  
  
  METHODS
  Between 10 September 2009 and 27 March 2010, individual characteristics and water consumption data were obtained from 298 children. Venous blood samples were collected (one per child) and a total of five 1-L samples of water per home were drawn from the kitchen tap. A second round of water collection was performed between 22 June 2011 and 6 September 2011 on a subsample of houses. Pb analyses used inductively coupled plasma mass spectroscopy. Multiple linear regressions were used to estimate the association between CWLEI and BPb.
  
  
  RESULTS
  Each 1-unit increase in CWLEI multiplies the expected value of BPb by 1.10 (95% CI: 1.06, 1.15) after adjustment for confounders. Mean BPb was significantly higher in children in the upper third and fourth quartiles of CWLEI (0.7-1.9 and ≥ 1.9 μg/kg of body weight) compared with the first (< 0.2 μg/kg) after adjusting for confounders (19%; 95% CI: 0, 42% and 39%; 95% CI: 15, 67%, respectively). The trends analysis yielded a p-value < 0.0001 after adjusting for confounders suggesting a dose-response relationship between percentiles of CWLEI and BPb.
  
  
  CONCLUSIONS
  In children 1-5 years of age, BPb was significantly associated with water lead concentration with an increase starting at a cumulative lead exposure of ≥ 0.7 μg Pb/kg of body weight. In this age group, an increase of 1 μg/L in water lead would result in an increase of 35% of BPb after 150 days of exposure.
authors.affiliation: Axe Santé des populations et pratiques optimales en Santé, Centre de recherche du CHU (Centre hospitalier universitaire) de Québec, Québec, Québec, Canada.
authors.forename: Gerard
authors.initials: G
authors.lastname: Ngueta
authors.forename: Belkacem
authors.initials: B
authors.lastname: Abdous
authors.forename: Robert
authors.initials: R
authors.lastname: Tardif
authors.forename: Julie
authors.initials: J
authors.lastname: St-Laurent
authors.forename: Patrick
authors.initials: P
authors.lastname: Levallois
mesh_terms: D002675:Child, Preschool; D060766:Drinking Water / Q000737:chemistry*; D004781:Environmental Exposure / Q000032:analysis*; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood*; D016014:Linear Models; D011792:Quebec; D014874:Water Pollutants, Chemical / Q000097:blood*
chemical_list: D060766:Drinking Water; D014874:Water Pollutants, Chemical; D007854:Lead