Toxoplasma gondii infection and the risk of adult glioma in two prospective studies

Abstract

Toxoplasma gondii (T gondii) is a common parasite that shows affinity to neural tissue and may lead to the formation of cysts in the brain. Previous epidemiologic studies have suggested an association between glioma and increased prevalence of T gondii infection, but prospective studies are lacking. Therefore, we examined the association between prediagnostic T gondii antibodies and risk of glioma in two prospective cohorts using a nested case‐control study design. Cases and matched controls were selected from the American Cancer Society's Cancer Prevention Study‐II Nutrition Cohort (CPSII‐NC) (n = 37 cases and 74 controls) and the Norwegian Cancer Registry's Janus Serum Bank (Janus) (n = 323 cases and 323 controls). Blood samples collected prior to diagnosis were analyzed for antibodies to two T gondii surface antigens (p22 and sag‐1), with individuals considered seropositive if antibodies to either antigen were detected. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for each cohort. In both cohorts, a suggestive increase in glioma risk was observed among those infected with T gondii (OR: 2.70; 95% CI: 0.96‐7.62 for CPSII‐NC; OR: 1.32, 95% CI: 0.85‐2.07 for Janus), particularly among participants with high antibody titers specific to the sag‐1 antigen (CPSII‐NC OR: 3.35, 95% CI: 0.99‐11.38; Janus OR: 1.79, 95% CI: 1.02‐3.14). Our findings provide the first prospective evidence of an association between T gondii infection and risk of glioma. Further studies with larger case numbers are needed to confirm a potential etiologic role for T gondii in glioma.

Infratentorial Stereotactic Biopsy of Brainstem and Cerebellar Lesions

“…Although the parasite forms cysts preferentially in the brain and a variety of brain cells, including astrocytes and neurons, can be infected, the relationship between T. gondii infection and brain tumors is scarcely described in the literature [ 30 ]. Schuman et al showed that astrocytoma patients were significantly more likely than controls to have antibodies to T. gondii [ 20 ], and there is some prospective evidence of an association between T. gondii infection and risk of glioma [ 31 ]. Moreover, in epidemiological studies, T. gondii seropositivity among brain tumor patients (18.3%) was significantly ( p < 0.05) higher than that of healthy controls (8.6%) [ 32 ].…”

Epidemiology of Brain and Other CNS Tumors

“…(continued) In a relatively small study of serum samples from two separate cohorts antibodies to T. gondii were significantly associated (OR: 2.70; 95% CI: 0.96-7.62; OR: 1.32, 95% CI: 0.85-2.07) with glioma risk before diagnosis, eliminating reverse causation biasing the association[52]. Further serologic studies examining T. gondii are needed.…”

The Case for Toxoplasma gondii in Psychosis and Other Human Diseases

“…A recent meta-analysis that included all 16 studies, with 3771 epileptic patients and 4026 healthy controls, reported an odds ratio of 1.72, p = 0.001 [91,92]. In summary, two out of the three studies of meningiomas and four out of the five studies of gliomas reported a statistically significant association between the brain cancer and infection with T. gondii [93][94][95][96].…”