Chlamydia Pneumoniae Seropositivity and Cardiovascular Risk Factors: The InCHIANTI Study

Objectives: To assess the prevalence of Chlamydia pneumoniae (CP) seropositivity and test the hypothesis that CP infection (CPI) is associated with cardiovascular (CV) risk factors and levels of inflammatory biomarkers. Design: Cross‐sectional survey. Setting: Representative sample of the residents of Greve in Chianti and Bagno a Ripoli, two small towns located in the Chianti geographic area (Tuscany, Italy). Participants: A total of 1,304 (age‐range: 20–103, 79% aged≥65) participants of the InCHIANTI study. Measurements: CP seropositivity was assessed using immunofluorescence. Previous CPI was defined as immunoglobulin (Ig) G ≥1/16 and <1/256, and recent CPI was defined as IgG ≥1/512 or IgM ≥1/16. Inflammatory markers included interleukin (IL)‐6, soluble IL‐6 receptor (sIL‐6r), tumor necrosis factor‐alpha (TNF‐α), IL‐1β, IL‐1 receptor antagonist (IL‐1ra), iron, ferritin, and C‐reactive protein (CRP). CV risk factors included smoking, body mass index (BMI), lipid profile, and hypertension. Results: The prevalence of CP seropositivity was 75%, increased with age, and was higher in men than in women ( P <.01). CPI was not associated with IL‐1β, IL‐1ra, iron, ferritin, CRP, BMI, lipids, and smoking. After adjusting for age and sex, previous or recent CPI was associated with higher TNF‐α ( P <.01), IL‐6 ( P <.03), sIL‐6R ( P <.01), and hypertension ( P <.02). In additional age and sex‐adjusted models, the associations between CPI and TNF‐α, IL‐6, sIL‐6r, and hypertension appeared to be mutually independent. Conclusion: CP seropositivity is highly prevalent in the older population and is a significant, independent correlate of hypertension and circulating levels of TNF‐α, IL‐6, and sIL‐6r.