Objective: Our aim was to study the effect of exposure to four infections on fat mass.
Research methods and procedures: This was a cross-sectional study of healthy middle-aged men from the general population (n = 74). Each study subject's serum was tested for specific IgG class antibodies against herpes simplex virus (HSV)-1, HSV-2, enteroviruses, and Chlamydia pneumoniae through the use of quantitative in vitro enzyme-linked immunosorbent assays (ELISAs). A total pathogen burden score based on these seropositivities [Quantitative Seropositivity Index (QSI)] was constructed. Fat mass was measured by bioelectrical impedance.
Results: We observed significant relationships between the HSV-1 titer and fat mass and percentage fat mass. The associations were stronger when considering the infection burden. The QSI was significantly associated with fat mass (r = 0.30, p = 0.009) and percentage fat mass (r = 0.27, p = 0.01). Those subjects in the highest tertile of fat mass showed significantly higher QSI (259.5 +/- 74.1 vs. 206.9 +/- 78.2, p = 0.007). In subjects that were seropositive for Enteroviruses, the relationship between the QSI and fat mass was strengthened (r = 0.51, p = 0.02). In a multivariate regression analysis, the QSI, independently of age and C-reactive protein, contributed to 9% of fat mass variance.
Discussion: Pathogen burden showed an association with fat mass. Subjects with increased fat mass could be more susceptible to developing multiple infections resulting in a chronic low-grade inflammation. We can not exclude the possibility that exposure to multiple infections leads to increased fat mass.