Chronic Chlamydia pneumoniae infection as a risk factor for coronary heart disease in the Helsinki Heart Study.

Abstract

OBJECTIVE:

To investigate in the prospective Helsinki Heart Study, whether chronic Chlamydia pneumoniae infection, indicated by elevated antibody titers against the pathogen, chlamydial lipopolysaccharide-containing immune complexes, or both, is a risk factor for coronary heart disease.

DESIGN AND SETTING:

The Helsinki Heart Study was a randomized, double-blind, 5-year clinical trial to test the efficacy of gemfibrozil in reducing the risk for coronary heart disease. Participants were randomized to receive either gemfibrozil (2046 patients) or placebo (2035 patients). Fatal and nonfatal myocardial infarction and sudden cardiac death were the main study end points. Serum samples were collected at 3-month intervals from all patients.

PATIENTS:

One hundred forty cardiac events occurred during the follow-up period. Serum samples from 103 case patients obtained 3 to 6 months before a cardiac end point were matched with those from controls for time point, locality, and treatment. Samples were tested for markers of chronic chlamydial infection.

MEASUREMENTS:

Immunoglobulin A (IgA) and G (IgG) antibodies to C. pneumoniae were measured using the microimmunofluorescence method. Lipopolysaccharide-containing immune complexes were measured using two antigen-specific enzyme immunoassays, the lipopolysaccharide-capture and immunoglobulin M (IgM)-capture methods.

MAIN RESULTS:

Using a conditional logistic regression model, odds ratios for the development of coronary heart disease were 2.7 (95% CI, 1.1 to 6.5) for elevated IgA titers, 2.1 (CI, 1.1 to 3.9) for the presence of immune complexes, and 2.9 (CI, 1.5 to 5.4) for the presence of both factors. If we adjusted for other coronary heart disease risk factors such as age, hypertension, and smoking, the corresponding values would be 2.3 (CI, 0.9 to 6.2), 1.8 (CI, 0.9 to 3.6), and 2.6 (CI, 1.3 to 5.2), respectively.

CONCLUSION:

The results suggest that chronic C. pneumoniae infection may be a significant risk factor for the development of coronary heart disease.

• Authors: P Saikku, M Leinonen, L Tenkanen, E Linnanmäki, M R Ekman, V Manninen, M Mänttäri, M H Frick, J K Huttunen
• Journal: Annals of internal medicine (Ann Intern Med) Vol. 116 Issue 4 Pg. 273-8 (Feb 15 1992) ISSN: 0003-4819 [Print] United States
• PMID: 1733381 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Bacterial
• Antigen-Antibody Complex
• Immunoglobulin A
• Immunoglobulin G
• Lipopolysaccharides

Topics

• Adult
• Antibodies, Bacterial (blood)
• Antigen-Antibody Complex (blood, chemistry)
• Chlamydia Infections (complications, immunology)
• Chlamydophila pneumoniae (immunology)
• Chronic Disease
• Coronary Disease (immunology, microbiology)
• Humans
• Immunoglobulin A (blood)
• Immunoglobulin G (blood)
• Lipopolysaccharides (blood, immunology)
• Male
• Middle Aged
• Odds Ratio
• Prospective Studies
• Risk Factors