Association of Toxoplasma gondii seropositivity with type 2 diabetes mellitus: a meta-analysis.

Background: Toxoplasma gondii (T. gondii) infection has been associated with type 2 diabetes mellitus (T2DM) through mechanisms involving chronic inflammation and immune dysregulation. However, prior meta-analyses were limited by their inability to distinguish between T2DM and type 1 diabetes, as well as the lack of antibody-based stratification. Methods: A comprehensive search was conducted on PubMed, Google Scholar, and EBSCOhost up to July 4, 2025, for observational studies reporting T. gondii seropositivity among T2DM patients. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup, sensitivity, and publication bias analyses were also conducted to strengthen the study results further. Results: Eleven case-control studies comprising 1,956 cases and 1,423 controls were included in the analysis. A significant association was found between T. gondii seropositivity and T2DM (OR: 2.21; 95% CI: 1.47-3.33; I² = 82%). IgG seropositivity demonstrated a consistent significant association (OR: 2.26; 95% CI: 1.45-3.53), whereas IgM seropositivity reached significance only in sensitivity analyses (OR: 5.65; 95% CI: 1.61-19.80). No publication bias was identified. Conclusion: T. gondii seropositivity is associated with an increased risk of T2DM, which may suggest a potential infectious component in the pathogenesis of diabetes. Further research involving larger, high-quality studies is warranted.