title: Asthma, bronchial hyper-responsiveness and Chlamydophila (Chlamydia) pneumonia infection in adult Thai population.
abstract: BACKGROUND
  The associations between Chlamydophila (Chlamydia) pneumonia infection and chronic asthma or bronchial hyper-responsiveness (BHR) have been inconclusive.
  
  
  OBJECTIVE
  We aimed to determine the association between C. pneumonia infection and asthma as well as BHR in the adult Thai population.
  
  
  METHODS
  This nested case-control study retrieved the data from a nation-wide Respiratory Health Survey (2001-02) in the adult population (age 20-44 year) in Thailand. Each subject underwent questionnaire interview, spirometry, bronchoprovocative test, skin prick test for common aeroallergens and venous blood collection. Subjects with BHR (n = 79) including those with asthma (n = 52), were randomly selected as cases. Subjects without BHR or asthma were also randomly selected as the control (n = 137). We used the stored serums for the C. pneumonia serologic assay including IgA, IgG and IgM by microimmunofluorescence (MIF) technique.
  
  
  RESULTS
  There is no significant relationship between chronic Chlamydia infection (IgG > or = 1:512 and IgA > or = 1:40) and BHR or asthma. Higher IgM was found in subjects with BHR when compared with the control group (p = 0.04). The IgM titer > or = 1:10 was associated with BHR with borderline significance (odds ratio 1.98; 95% CI 0.98-4.00; p = 0.05). Logistic regression analysis revealed no evidence of confounding effects for age, sex and atopy. However mite allergy seems to be an effect modifier of the relationship between the recent Chlamydia infection and BHR.
  
  
  CONCLUSIONS
  The present study does not support the hypothesis about the association between persistent C. pneumonia infection and chronic asthma. However the recent infection may be related with bronchial hyper-responsiveness particularly in those without allergy to house dust mite.
authors: Division of Respiratory Disease and Tuberculosis, Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. siwds@mahidol.ac.th
authors: Wanchai
authors: W
authors: Dejsomritrutai
authors: Sontana
authors: S
authors: Siritantikorn
authors: Arth
authors: A
authors: Nana
mesh_terms: D000328:Adult; D001249:Asthma / Q000382:microbiology* / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000382:microbiology*; D016022:Case-Control Studies; D023521:Chlamydophila Infections / Q000453:epidemiology*; D016993:Chlamydophila pneumoniae; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D013785:Thailand; D055815:Young Adult