title: Environmental risk factors for Lyme disease identified with geographic information systems.
abstract: OBJECTIVE
  A geographic information system was used to identify and locate residential environmental risk factors for Lyme disease.
  
  
  METHODS
  Data were obtained for 53 environmental variables at the residences of Lyme disease case patients in Baltimore County from 1989 through 1990 and compared with data for randomly selected addresses. A risk model was generated combining the geographic information system with logistic regression analysis. The model was validated by comparing the distribution of cases in 1991 with another group of randomly selected addresses.
  
  
  RESULTS
  In crude analyses, 11 environmental variables were associated with Lyme disease. In adjusted analyses, residence in forested areas (odds ratio [OR] = 3.7, 95% confidence interval [CI] = 1.2, 11.8), on specific soils (OR = 2.1, 95% CI = 1.0, 4.4), and in two regions of the county (OR = 3.5, 95% CI = 1.6, 7.4) (OR = 2.8, 95% CI = 1.0, 7.7) was associated with elevated risk of getting Lyme disease. Residence in highly developed regions was protective (OR = 0.3, 95% CI = 0.1, 1.0). The risk of Lyme disease in 1991 increased with risk categories defined from the 1989 through 1990 data.
  
  
  CONCLUSIONS
  Combining a geographic information system with epidemiologic methods can be used to rapidly identify risk factors of zoonotic disease over large areas.
authors.affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD 21205, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Glass
authors.forename: B S
authors.initials: BS
authors.lastname: Schwartz
authors.forename: J M
authors.initials: JM
authors.lastname: Morgan
authors.forename: D T
authors.initials: DT
authors.lastname: Johnson
authors.forename: P M
authors.initials: PM
authors.lastname: Noy
authors.forename: E
authors.initials: E
authors.lastname: Israel
mesh_terms: D004781:Environmental Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D005843:Geography; D006801:Humans; D007256:Information Systems; D016015:Logistic Models; D008193:Lyme Disease / Q000453:epidemiology*; D008396:Maryland / Q000453:epidemiology; D016017:Odds Ratio; D012111:Residence Characteristics; D012307:Risk Factors