A pilot study on the association between double positive Chlamydia pneumoniae serology and serum lipid indices alterations in obese adult females.

Aims: To study the relationship between Chlamydia pneumoniae serologic status and serum lipid abnormalities in apparently healthy obese female subjects living in urban areas.

Main Methods: Serum samples from 117 apparently healthy females (mean age 50 years), classified as overweight/obese (OW/OB,n=74) or normal weight (NW,n=43) according to their body mass index (BMI), were tested for specific IgG and IgA antibodies against C. pneumoniae using ELISA assay. Serum triglycerides (TG), total cholesterol (TChol) and high-density lipoprotein cholesterol (HDLChol) concentrations were measured using enzymatic methods. Serum low-density lipoprotein cholesterol (LDLChol) was calculated using the Friedewald formula. Lifestyle data for all subjects were collected using a validated self-reported questionnaire.

Key Findings: The prevalence of C. pneumoniae infection, as indicated by single positive serology (IgG(+) or IgA(+)), was significantly higher among the OW/OB females than the NW subjects (38.5%vs.27.0%,p=0.021). Females with double-positive serology (IgG(+)/IgA(+)) in the OW/OB group indicated significantly higher (p<0.05) mean serum TG, TChol and LDLChol levels compared to the double seronegatives (IgG(-)/IgA(-)) from this group. On the contrary, no statistical differences (p>0.05) were observed in these serum lipid indices between subjects in the NW group with considered opposite C. pneumoniae serology. Multivariate regression analysis on the 42 double-seropositive subjects, including both OW/OB and NW females and adjusted for such potential confounders as age, BMI and lifestyle factors, showed a significant association of double-positive C. pneumoniae serology with serum TG (β=0.244;p=0.049),LDLChol (β=0.332;p=0.037) and TChol-to-HDLChol ratio (β=0.313;p=0.042).

Significance: These results suggest that possible chronic C. pneumoniae infection is a potential non-dietary factor in modification of the serum lipid profile in the adult OW/OB females.