title: Incident asthma and Mycoplasma pneumoniae: A nationwide cohort study.
abstract: BACKGROUND
  Previous studies investigating the relationship between Mycoplasma pneumoniae and incident asthma in the general population have been inconclusive.
  
  
  OBJECTIVE
  We conducted a nationwide cohort study to clarify this relationship.
  
  
  METHODS
  Using the National Health Insurance Research Database of Taiwan, we identified 1591 patients with M pneumoniae infection (International Classification of Diseases, Ninth Revision, Clinical Modification code 4830) given diagnoses between 2000 and 2008. We then frequency matched 6364 patients without M pneumoniae infection from the general population according to age, sex, and index year. Cox proportional hazards regression analysis was performed to determine the adjusted hazard ratio (aHR) of the occurrence of asthma in the M pneumoniae cohort compared with that in the non-M pneumoniae cohort.
  
  
  RESULTS
  Regardless of comorbidities and the use of antibiotic or steroid therapies, patients with M pneumonia infection had a higher risk of incident asthma than those without it. The aHR of asthma was 3.35 (95% CI, 2.71-4.15) for the M pneumoniae cohort, with a significantly higher risk when patients were stratified by age, sex, follow-up time, and comorbidities, including allergic rhinitis, atopic dermatitis, or allergic conjunctivitis. Patients with M pneumoniae infection had a higher risk of having early-onset (age, <12 years; aHR, 2.87) and late-onset (age, ≥12 years; aHR, 3.95) asthma. The aHR was also higher within the less than 2-year follow-up in the M pneumoniae cohort (aHR, 4.41; 95% CI, 3.40-5.74) than in the cohort without the infection.
  
  
  CONCLUSIONS
  This study found that incident cases of early-onset and late-onset asthma are closely related to M pneumoniae infection, even in nonatopic patients.
authors.affiliation: Department of Chest Medicine and Family Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan; Chia Nan University of Pharmacy and Science, Tainan, Taiwan; Meiho University, Pingtung, Taiwan.
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Yeh
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan; School of Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Wang
authors.affiliation: School of Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Wu-Huei
authors.initials: WH
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University Hospital, Taichung, Taiwan; Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan. Electronic address: d10040@mail.cmuh.org.tw.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D001249:Asthma / Q000453:epidemiology / Q000382:microbiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011019:Pneumonia, Mycoplasma / Q000150:complications*; D016016:Proportional Hazards Models; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
keywords: Mycoplasma pneumoniae; antibiotic; asthma; cohort study; steroid