Background and objective: Many patients with brain infarction (BI) lack traditional risk factors suggesting that other factors including infectious agents might contribute to stroke risk. We investigated Chlamydia pneumoniae infection in the largest cohort of patients with BI according to etiologic subtypes and carotid atherosclerosis.
Methods: We measured serum IgG and IgA to C pneumoniae by microimmunofluorescence in 483 BI cases and 483 controls matched on age, sex and center. IgG¡Ý1/32 and IgA¡Ý1/24 were considered positive. Cases with BI proven by MRI were consecutively recruited and were classified into etiological subtypes. Carotid atherosclerosis (intima-media thickness, plaques, stenosis) was evaluated by duplex ultrasonography in all subjects following the same method and with central reading.
Results: C pneumoniae IgG seropositivity was not associated with BI (Adjusted OR 1.10, 95% CI 0.80-1.51) and did not increase the risk of any etiological subtype. Overall, C pneumoniae IgA was not associated with BI (Adjusted OR 1.54, 95% CI 0.84-2.81) but there was a significant interaction with hypertension. IgA seropositivity increased the BI risk in patients without hypertension (Adjusted OR 2.79, 95%IC 1.15 to 6.74). When stratifying BI into subtypes, IgA seropositivity increased the risk of BI of unknown cause but without significant heterogeneity. There was neither association with atherothrombotic, lacunar and cardioembolic BI nor with carotid intima-media thickness, carotid plaques or stenosis.
Conclusions: We found no evidence that C pneumoniae seropositivity is associated with carotid atherosclerosis and BI, regardless with etiologic subtypes; but might be associated with a excess risk of BI in normotensive patients.
- chlamydia pneumoniae
- etiological subtype