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Asthma and risk of non-respiratory tract infection: a population-based case–control study
  1. Duk Won Bang1,2,
  2. Hyeon J Yang3,
  3. Eell Ryoo1,4,
  4. Majdi N Al-Hasan5,
  5. Brian Lahr6,
  6. Larry M Baddour7,
  7. Barbara P Yawn8,
  8. Young J Juhn1,9
  1. 1Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA
  2. 2Department of Internal Medicine, Soonchunhyang University Hospital, Seoul, South Korea
  3. 3Department of Pediatrics, Soonchunhyang University Hospital, Seoul, South Korea
  4. 4Department of Pediatrics, Gil Hospital, Gachon University School of Medicine, Inchon, South Korea
  5. 5Department of Medicine, University of Kentucky Medical Center, Lexington, Kentucky, USA
  6. 6Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
  7. 7Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
  8. 8Department of Research, Olmsted Medical Center, Rochester, Minnesota, USA
  9. 9Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA
  1. Correspondence to Dr Young J Juhn; juhn.young{at}


Objectives Asthmatics have increased risks of airway-related infections. Little is known about whether this is true for non-airway-related serious infections such as Escherichia coli bloodstream infection (BSI). We assessed whether asthma is associated with a risk of developing community-acquired E coli BSI.

Design The study was designed as a population-based retrospective case–control study.

Setting This population-based study was conducted in Olmsted County, Minnesota.

Participants The study included 259 all eligible community-acquired E coli BSI cases in Olmsted County, MN between 1998 and 2007 and 259 birthday-matched, gender-matched and residency-matched controls.

Primary and secondary outcome measures Only community-acquired E coli BSI cases as the primary outcome was included. Asthma status as an exposure was ascertained by predetermined criteria. An adjusted OR and 95% CI for the association between asthma and risk of community-acquired E coli BSI was calculated using conditional logistic regression.

Results Of 259 eligible cases, 179 (69%) were women and mean age was 61±22 years. Of the 259 cases 37 (14%) and 16 (6%) of 259 controls had a prior history of asthma (adjusted OR 2.74; 95% CI 1.11 to 6.76; p=0.029). The population attributable risk of asthma for community-acquired E coli BSI was 9%. Although not statistically significant, there was a borderline association between having a history of food allergy and increased risk of community-acquired E coli BSI (6% vs 2%; adjusted OR 3.51; 95% CI 0.94 to 13.11; p=0.062).

Conclusions Based on the findings of the current population-based, case–control investigation, a history of asthma may be associated with risk of community-acquired E coli BSI. The impact of asthma on risk of microbial infections may go beyond airways.

  • Epidemiology

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