title: Residential pesticides and childhood leukemia: a systematic review and meta-analysis.
abstract: OBJECTIVE
  We conducted a systematic review and meta-analysis of previous observational epidemiologic studies examining the relationship between residential pesticide exposures during critical exposure time windows (preconception, pregnancy, and childhood) and childhood leukemia.
  
  
  METHODS
  Searches of MEDLINE and other electronic databases were performed (1950-2009). Reports were included if they were original epidemiologic studies of childhood leukemia, followed a case-control or cohort design, and assessed at least one index of residential/household pesticide exposure/use. No language criteria were applied.
  
  
  METHODS
  Study selection, data abstraction, and quality assessment were performed by two independent reviewers. Random effects models were used to obtain summary odds ratios (ORs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  Of the 17 identified studies, 15 were included in the meta-analysis. Exposures during pregnancy to unspecified residential pesticides (summary OR = 1.54; 95% CI, 1.13-2.11; I2 = 66%), insecticides (OR = 2.05; 95% CI, 1.80-2.32; I2 = 0%), and herbicides (OR = 1.61; 95% CI, 1.20-2.16; I2 = 0%) were positively associated with childhood leukemia. Exposures during childhood to unspecified residential pesticides (OR = 1.38; 95% CI, 1.12-1.70; I2 = 4%) and insecticides (OR = 1.61; 95% CI, 1.33-1.95; I2 = 0%) were also positively associated with childhood leukemia, but there was no association with herbicides.
  
  
  CONCLUSIONS
  Positive associations were observed between childhood leukemia and residential pesticide exposures. Further work is needed to confirm previous findings based on self-report, to examine potential exposure-response relationships, and to assess specific pesticides and toxicologically related subgroups of pesticides in more detail.
authors.affiliation: McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, Ottawa, Canada. mturner@uottawa.ca
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Turner
authors.forename: Donald T
authors.initials: DT
authors.lastname: Wigle
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
mesh_terms: D002648:Child; D016001:Confidence Intervals; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006798:Housing; D006801:Humans; D007938:Leukemia / Q000453:epidemiology / Q000209:etiology*; D016017:Odds Ratio; D010575:Pesticides / Q000633:toxicity*; D011247:Pregnancy
chemical_list: D004785:Environmental Pollutants; D010575:Pesticides