Previous exposure to Chlamydia pneumoniae, Helicobacter pylori and other infections in Canadian patients with ischemic heart disease.

OBJECTIVE

Previous exposures to Chlamydia pneumoniae (CP), Helicobacter pylori (HP) or cytomegalovirus (CMV) have been associated with atherosclerotic heart disease. These associations were studied in Canadian patients, and the exposure to five infections measured.

DESIGN

Case-control study.

SETTING

In the coronary care units (Hamilton General site, Henderson General site, McMaster University Medical Centre site of the Hamilton Health Sciences Corporation and St Joseph's Hospital) and from the regional angiography suite (Hamilton General site), Hamilton, Ontario.

PATIENTS AND

METHODS

One hundred seven consecutive patients presenting with myocardial infarction or unstable angina (coronary care unit patients), or with previous angina or myocardial infarction (angiography suite patients), were compared with 107 family practice or outpatient clinic control subjects.

INTERVENTIONS: Cardiovascular risk factors were measured, as was serology for CP, HP, CMV, adenovirus and hepatitis A virus. Statistical analysis was by logistic regression, adjusted for age and sex.

RESULTS

Exposure to CP was more frequent in patients than in control subjects (85.4% versus 70.3%, adjusted odds ratio [OR] 2.3, 95% CI 1.1 to 5.1, P=0.03). Dividing CP immunoglobulin G absorbance into quarters, with the lowest quarter as the reference group, the adjusted ORs were 2.8, 3.0 and 4.3, respectively, for the second, third and fourth quarters (P=0.001 for trend). The seroprevalences of HP (61.7%), CMV (64.0%), adenovirus (75.6%) and hepatitis A virus (59.2%) were high, with no association with disease.

CONCLUSIONS

An association was found between heart disease and previous exposure to CP, with a stepwise increase in ORs at higher antibody levels, whereas no association was found with HP, CMV or other infections. A prospective validation of this association is needed.