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

OBJECTIVE

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

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.

RESULTS

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).

CONCLUSIONS

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.