Correlation between latent toxoplasmosis and thyroid hormone levels in sera of schizophrenic patients

Abstract

Latent toxoplasmosis is a prevalent chronic infection caused by a protozoan parasite called Toxoplasma gondii. Recent studies have shown that T. gondii may affect thyroid hormone levels and thus induce behavioral alteration. However, this correlation has been inadequately investigated. Therefore, we aimed to examine the relationship between latent toxoplasmosis and thyroid hormone levels in schizophrenic patients. For this purpose, blood samples and sociodemographic information were collected from 101 schizophrenic patients attending three psychiatric hospitals in Kurdistan region of Iraq. Anti-T. gondii-IgG antibodies and thyroid hormones levels (TSH, T3, T4) were determined in sera of all patients using ELISA technique. Anti-T. gondii-IgG antibodies were detected in sera of 40 (39.6%) out of 101 schizophrenic patients. Logistic regression analysis showed significant association between toxoplasmosis and schizophrenic patients in 50-60 age group (OR=6.177, p=0.05), and un-employed patients (OR=3.562, p=0.05). Data analysis showed non-significant difference in TSH levels between IgG seropositive and IgG seronegative group (p>0.05). On the other hand, T4 levels were significantly higher in the seropositive (10.16 ± 2.61) than seronegative group (7.01 ± 2.01), with highly significant positive correlation between IgG and T4 levels (p= 0.001). Finally, T3 levels were significantly higher in the seropositive (1.91 ± 0.5) than seronegative group (1.12 ± 0.43), with non-significant positive correlation between IgG and T3 levels (p=0.30). Owing to the fact that there was statistically significant increase in thyroid hormone levels in T. gondii seropositive patients, our results suggest that there is a significant association between toxoplasmosis and thyroid hormone levels in schizophrenic patients.