title: Persistent Chlamydia Pneumoniae serology is related to decline in lung function in women but not in men. Effect of persistent Chlamydia pneumoniae infection on lung function.
abstract: BACKGROUND
  Chlamydia pneumoniae (C pn) infection causes an acute inflammation in the respiratory system that may become persistent, but little is known about the long-term respiratory effects of C pn infections.
  
  
  OBJECTIVE
  To estimate the long term respiratory effects of C pn with change in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) as a main outcome variable.
  
  
  METHODS
  The study comprised of 1109 subjects (500 men and 609 women, mean age 28 ± 6 years) that participated in the Reykjavik Heart Study of the Young. Spirometry and blood samples for measurements of IgG antibodies for C pn were done at inclusion and at the end of the follow-up period (mean follow-up time 27 ± 4 years).
  
  
  RESULTS
  Having IgG against C pn at both examinations was significantly associated to a larger decrease in FEV1 (6 mL/year) and FVC (7 mL/year) in women but not in men. In women the association between C pn and larger FEV1 decline was only found in women that smoked at baseline where having C pn IgG was associated with 10 mL/year decline compared to smokers without C pn IgG. These results were still significant after adjustment for age, smoking and change in body weight.
  
  
  CONCLUSIONS
  Our results indicate that persistent C pn serology is related to increased decline in lung function in women but not in men. This effect was, however, primarily found in smoking women. This study is a further indication that the pathophysiological process leading to lung impairment may differ between men and women.
authors.affiliation: University of Iceland, Faculty of Medicine, Reykjavik, Iceland.
authors.forename: Thorarinn
authors.initials: T
authors.lastname: Gislason
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Guðdnason
authors.forename: Bryndis
authors.initials: B
authors.lastname: Benediktsdottir
authors.forename: Isleifur
authors.initials: I
authors.lastname: Olafsson
authors.forename: Thor
authors.initials: T
authors.lastname: Aspelund
authors.forename: Bjarni
authors.initials: B
authors.lastname: Thjodleifsson
authors.forename: Christer
authors.initials: C
authors.lastname: Janson
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D023521:Chlamydophila Infections / Q000382:microbiology* / Q000503:physiopathology*; D016993:Chlamydophila pneumoniae / Q000276:immunology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008168:Lung / Q000503:physiopathology*; D008297:Male; D018410:Pneumonia, Bacterial / Q000382:microbiology* / Q000503:physiopathology*; D012737:Sex Factors; D012907:Smoking / Q000503:physiopathology; D013147:Spirometry; D014797:Vital Capacity; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial