Public Health Implications of Latent Toxoplasmosis and Its Association With Type 2 Diabetes: A Case–Control Study in Qazvin, North‐Western Iran

ABSTRACT Introduction Toxoplasma gondii is a worldwide‐distributed zoonotic parasite, causing latent infections in humans. Increasing evidence has suggested a possible link between toxoplasmosis and diabetes mellitus (DM), though data from Iran are limited. This study was conducted to determine the seroprevalence of latent T. gondii infection and its association with diabetes in Qazvin province, north‐western Iran. Materials and Methods In this case‐control study, 350 patients with type 2 diabetes mellitus and 350 non‐diabetic controls were recruited from clinical laboratories in Qazvin province. Anti‐ T. gondii IgG antibodies were detected by enzyme‐linked immunosorbent assay (ELISA). Data on sociodemographic variables and exposures were obtained by structured questionnaires. Statistical analyses, such as χ 2 , t ‐test, and logistic regression, were performed using the STATA software version 17. Results Overall, 21.1% (148/700) of the participants were seropositive for T. gondii IgG antibodies. Compared with the controls, diabetic patients had a significantly higher seroprevalence of infection (27.7% vs. 14.6%). Seropositivity was positively associated with older age and rural residence, whereas no association was found with respect to sex, education, occupation, or dietary habits (consumption of raw or undercooked meat, raw eggs, and unwashed vegetables). Multivariate logistic regression, adjusted for age and residence, identified diabetes status as a significant factor associated with T. gondii seropositivity (adjusted OR = 2.62, 95% CI: 1.74–3.95, p < 0.001). Conclusions The results indicated a higher seroprevalence of latent T. gondii infection in diabetic patients from Qazvin province, suggesting an epidemiological association between toxoplasmosis and diabetes. Significant correlates identified included age and living environment. These findings underscore a notable epidemiological link between latent toxoplasmosis and type 2 diabetes, highlighting the need for integrated public health attention to this association in endemic regions.