title: Risk factors for domestic acquisition of legionnaires disease. Ohio legionnaires Disease Group.
abstract: BACKGROUND
  Legionnaires disease is a common cause of adult pneumonia. Outbreaks of legionnaires disease have been well described, but little is known about sporadically occurring legionnaires disease, which accounts for most infections. Exposure to contaminated residential water sources is I plausible means of disease acquisition.
  
  
  METHODS
  Employing a matched case-control study design in 15 hospitals in 2 Ohio counties, we prospectively enrolled 146 adults diagnosed as having nonepidemic, community-acquired legionnaires disease and compared each with 2 hospital-based control patients, matched for age, sex, and underlying illness category. An interview regarding potential exposures was followed by a home survey that included sampling residential sources for Legionella. Interview and home survey data were analyzed to estimate the risk of acquiring legionnaires disease associated with various exposures.
  
  
  RESULTS
  Multivariate analysis showed that a nonmunicipal water supply (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.17-4.37), recent residential plumbing repair (OR, 2.39; 95% CI, 1.10-5.18), and smoking (OR, 3.48; 95% CI, 2.09-5.79) were independent risk factors for legionnaires disease. Univariate analysis suggested that electric (vs gas) water heaters (OR, 1.97; 95% CI, 1.10-3.52), working more than 40 hours weekly (OR, 2.13; 95% CI, 1.12-4.07), and spending nights away from home before illness (OR, 1.68; 95% CI, 1.03-2.74) were additional possible risk factors. Lower chlorine concentrations in potable water and lower water heater temperatures were associated with residential Legionella colonization.
  
  
  CONCLUSIONS
  A proportion of sporadic cases of legionnaires disease may be residentially acquired and are associated with domestic potable water and disruptions in residential plumbing systems. Potential strategies to reduce legionnaires disease risk include consistent chlorination of potable water, increasing water heater temperatures, and limiting exposure to aerosols after domestic plumbing repairs.
authors.affiliation: Division of Bacterial and Mycotic Infections, Centers for Disease Control and Prevention, Atlanta, Ga, USA.
authors.forename: W L
authors.initials: WL
authors.lastname: Straus
authors.forename: J F
authors.initials: JF
authors.lastname: Plouffe
authors.forename: T M
authors.initials: TM
authors.lastname: File
authors.forename: H B
authors.initials: HB
authors.lastname: Lipman
authors.forename: B H
authors.initials: BH
authors.lastname: Hackman
authors.forename: S J
authors.initials: SJ
authors.lastname: Salstrom
authors.forename: R F
authors.initials: RF
authors.lastname: Benson
authors.forename: R F
authors.initials: RF
authors.lastname: Breiman
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000209:etiology*; D003428:Cross Infection / Q000209:etiology; D006798:Housing; D006801:Humans; D016952:Legionella pneumophila / Q000302:isolation & purification; D007877:Legionnaires' Disease / Q000175:diagnosis / Q000209:etiology*; D016015:Logistic Models; D016555:Matched-Pair Analysis; D008875:Middle Aged; D012307:Risk Factors; D012498:Sanitary Engineering; D012907:Smoking; D014881:Water Supply