<i>Mycoplasma pneumoniae</i> in Elderly Patients with Stroke

Abstract

BACKGROUND AND PURPOSE: Previous studies have suggested certain infections as potential risk factors for stroke. Chlamydia pneumoniae, an atypical respiratory pathogen, has been linked to atherosclerotic vascular diseases. Mycoplasma pneumoniae, another atypical respiratory micro-organism, can rarely cause stroke. We investigated whether serological markers of M. pneumoniae infection were associated with acute stroke or transient ischaemic attack (TIA) in elderly patients. METHODS: This case-control study was nested within the C-PEPS study - a case-control study on the seroprevalence of C. pneumoniae in elderly stroke and medical patients. Ninety-five incident cases of patients admitted consecutively with acute stroke or TIA, and 82 control subjects admitted concurrently with acute non-cardiopulmonary, non-infective disorders, were included in this study (both groups aged 65 years or older). Using commercial enzyme-linked immunosorbent assay (ELISA) kits, the presence of M. pneumoniae immunoglobulins IgA, IgG and IgM in patients' sera was determined. RESULTS: The seroprevalence of M. pneumoniae IgA, IgG and IgM in the stroke or TIA group (median age = 80) were 79, 61 and 6%, respectively. In the control group (median age = 80), the seroprevalence of respective M. pneumoniae IgA, IgG and IgM were 84, 50 and 11%. Using a logistic regression statistical model, adjusting for history of hypertension, smoking, diabetes mellitus, age and sex, history of ischaemic heart disease, and ischaemic electrocardiogram, the odds ratios of having a stroke or TIA in relation to M. pneumoniae IgA, IgG and IgM were 0.63 (95% confidence interval (CI) = 0.26-1.52, p = 0.31), 1.32 (95% CI = 0.66-2.64, p = 0.43) and 0.52 (95% CI = 0.14-1.92, p = 0.32), respectively. CONCLUSIONS: The study showed a high seroprevalence of M. pneumoniae in an elderly hospital population, using ELISA. Although the study ruled out M. pneumoniae seropositivity as a major risk factor for stroke in this elderly population, a smaller effect could not be excluded due to the small sample size. Future larger studies may be required to determine the precise role of M. pneumoniae infection in the pathogenesis of different subtypes of ischaemic stroke, in all age groups, and in different ethnic populations.