title: Chlamydia pneumoniae and the risk of first ischemic stroke : The Northern Manhattan Stroke Study.
abstract: OBJECTIVE
  Serological evidence of infection with Chlamydia pneumoniae has been associated with cardiovascular disease in multiple epidemiological studies. The data on its association with ischemic stroke are limited. We sought to determine whether chronic C pneumoniae infection is associated with ischemic stroke in a multi-ethnic population.
  
  
  METHODS
  The Northern Manhattan Stroke Study contains a population-based, case-control study component. Cases had first ischemic stroke and matched control subjects were derived through random digit dialing. Titers of IgG, IgA, and IgM antibodies specific for C pneumoniae were measured with the use of microimmunofluorescence, and titers >/=1:16 were considered positive. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjustment for medical, behavioral, and socioeconomic factors.
  
  
  RESULTS
  Eighty-nine cases and 89 control subjects were selected. Mean age among cases was 68.5+/-12.8 years; 53% were women and 15% of the subjects were white, 28% were black, and 54% were Hispanic. Elevated C pneumoniae IgA titers were significantly associated with risk of ischemic stroke after adjusting for other stroke risk factors (adjusted OR 4. 51, 95% CI 1.44 to 14.06). IgG titers were less strongly associated with stroke risk (adjusted OR 2.59, 95% CI 0.87 to 7.75). The association of IgA with stroke risk was detected in both younger and older groups, in men and women, and in whites, blacks, and Hispanics. There was also a significant continuous increase in risk associated with the log-transformation of the titer for IgA (adjusted OR 1.32, 95% CI 1.05 to 1.66) but not IgG.
  
  
  CONCLUSIONS
  Serological evidence of chronic infection with C pneumoniae is associated with risk of ischemic stroke in an urban, multi-ethnic population. IgA titers may be a better marker of this risk than are IgG titers. This association is independent of other vascular disease risk factors. Further prospective epidemiological studies of the effect of this infection on stroke risk are warranted.
authors.affiliation: Department of Neurology, College of Physicians and Surgeons, Columbia University, and the Columbia-Presbyterian Medical Center of New York Presbyterian Hospital, New York, NY, USA. mse13@columbia.edu
authors.forename: M S
authors.initials: MS
authors.lastname: Elkind
authors.forename: I F
authors.initials: IF
authors.lastname: Lin
authors.forename: J T
authors.initials: JT
authors.lastname: Grayston
authors.forename: R L
authors.initials: RL
authors.lastname: Sacco
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D044383:Black People; D002545:Brain Ischemia / Q000208:ethnology* / Q000382:microbiology*; D016022:Case-Control Studies; D002690:Chlamydia Infections / Q000208:ethnology* / Q000276:immunology; D016993:Chlamydophila pneumoniae; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D002537:Intracranial Arteriosclerosis / Q000208:ethnology / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009519:New York City / Q000453:epidemiology; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D020521:Stroke / Q000208:ethnology* / Q000382:microbiology*; D044465:White People; D001741:Black or African American
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G