Association between past infection with Chlamydia pneumoniae and body mass index, low-density lipoprotein particle size and fasting insulin

BACKGROUND: Chlamydia pneumoniae infection has been linked to the development of coronary heart disease (CHD), but its relationship to CHD risk factors is less clear. OBJECTIVE: To determine the relationship between past infection with C. pneumoniae and risk factors for CHD, including body weight amongst subjects with and without CHD. METHODS: Antibodies to C. pneumoniae and a range of CHD risk factors were determined in 170 subjects, of whom 43 had recent onset angina. Anthropometric, haemodynamic, lipid and metabolic measurements were obtained and related to antibody status in univariate and multivariate analyses. RESULTS: IgG seropositive (n = 62) did not differ from seronegative subjects in age but were significantly heavier (26.6 +/- 0.4 vs 25.5 +/- 0.3 kg/m2, P = 0.02). The prevalence of seropositivity was similar for subjects with and without CHD and for those with or without hypertension. Subjects with fasting insulin levels greater and those with LDL diameters below the median also had a significantly higher prevalence of seropositivity (45.3 vs 27.3%, P = 0.015 and 45.0 vs 29.4%, P = 0.045 respectively). However in multivariate analysis only body mass index remained significant (P < 0.05). Results were not explained by differences in socioeconomic class. CONCLUSION: Although the study has failed to find a greater prevalence of antibodies to C. pneumoniae amongst subjects with recent onset angina there were associations with a number of cardiovascular risk factors. An increase in body weight appears to underlie these relationships.