The Role of Toxoplasma gondii Infection on the Development of Neurocognitive Disorders in Traumatic Brain Injury Patients Open Access

Shanker, Lauren (2015)

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Neurocognitive disorders are an important adverse health outcome for Traumatic Brain Injury (TBI) patients. The etiology of neurocognitive disorders in TBI patients is currently not well understood. This study was conducted to test for the association between Toxoplasma gondii (TOXO) infection and the odds of psychosis and mood disorders in TBI patients. The data are a subset of 100 TBI patients attending the Atlanta Veteran's Affairs Medical Center from 2014 to 2015. TOXO is under investigation because it is thought to increase the risk of schizophrenia and suicide worldwide. There is minimal data that relates any infectious agents with worsening mental health outcomes for TBI patients. TOXO titer (the amount of anti-Toxoplasma IgG antibodies) was analyzed as a dichotomous variable and as a continuous variable due to evidence that TOXO exposure is not normally distributed and cut-off levels for seropositivity often differ by study. For the dichotomous variable, TOXO titer was categorized into two groups; seropositive (TOXO titer greater than or equal to 27 IU/mL) and seronegative (TOXO titer less than 27 IU/mL). Statistical analysis revealed a positive relationship between TOXO seropositivity and severity of head injury and age. Log-risk models using TOXO seropositivity or TOXO titer were fit to investigate the effect of TOXO on psychosis and mood disorders. The Crude Odds Ratio for the effect of TOXO seropositivity on psychosis was 3.50 (95% Confidence Interval: 0.46, 18.43). After adjusting for age and severity of head injury, the estimated effect of TOXO seropositivity on psychosis is 2.93 (95% Confidence Interval: 0.32, 2.05). The Crude Odds Ratio for the effect of TOXO titer on psychosis is 1.03 (95% Confidence Interval: 1.00, 1.06). The data suggest that increasing TOXO titer has a worsening effect on psychosis in TBI patients. Public health interventions that call for better treatment options for TOXO or reduce the likelihood of TOXO infection can have the potential to reduce the burden of neurocognitive disorders in TBI patients.

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