Effects of Toxoplasma gondii infection and schizophrenia comorbidity on serum lipid profile: A population retrospective study from Eastern China

Introduction: Toxoplasma gondii (T. gondii), a parasitic protozoa that is associated with various psychiatric disorders. Both T. gondii infection and disturbed host's lipid profile are common in schizophrenia patients. However, the underlying pathophysiological mechanisms remain speculative. Also, the characteristics of serum lipid levels in schizophrenia patients comorbid with T. gondii infection are not clear. Therefore, it is necessary to explore the influence of chronic T. gondii infection on the characteristic physiological indexes of schizophrenia patients so as to provide some insights into finding target therapeutic drugs. Methods: In this study, the effect of chronic T. gondii infection on serum lipid profile was retrospectively analysed in 1719 schizophrenic patients and 1552 healthy subjects from Eastern China. Results: The overall prevalence of Immunoglobulin G (IgG) antibodies against T. gondii (17.98%) in schizophrenia patients was significantly higher than healthy controls (7.35%, chi 2 = 81.831, P = 0.000). Compared to T. gondii IgG-seronegative schizophrenia patients, IgG-seropositive group had higher high-density lipoprotein (HDL) (P = 0.000) and triglycerides (TG) (P = 0.000) levels, while total cholesterol (TC) (P = 0.000) levels showed an opposite tendency in IgG-seropositive cases. We also found significant correlation between T. gondii seropositivity and increased TG (P = 0.000) and TC levels (P = 0.000) in schizophrenia patients. Binary regression analysis also showed that decreased TC level was more common among schizophrenia patients with T. gondii seropositivity compared to seronegative subjects (OR = 0.617, 95%CI = 0.509-0.749, P = 0.000). Conclusion: Patients with chronic T. gondii infection and comorbid schizophrenia had higher HDL and TG levels, while cholesterol levels showed an opposite trend. To the best of our knowledge, this is the first report focus on the host's lipid profile of chronic T. gondii infection and comorbid schizophrenia patients.