There’s potential for increased risk of glioma following infection by Toxoplasma gondii (T gondii). These findings, from 2 prospective cohorts using a case control study design published in the International Journal of Cancer.

Participants who did not have cancer provided blood samples for the Cancer Prevention Study II Nutrition Cohort (CPSII-NC; n=101) and the Norwegian Cancer Registry’s Janus Serum Bank (n=646). Researchers then assessed cases of glioma and instance of T gondii among the study participants.

The mean age of participants in the CPSII-NC and Janus cohorts were 70 and 40 years, respectively, at time of blood donation. Glioma was diagnosed among 37 participants of the CPSII-NC and 323 participants of the Janus cohorts.


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There was increased risk for glioma among those who had sag-1 surface antigens, indicating past T gondii infection (odds ratio [OR], 3.35; 95% CI, 0.99-11.38; P =.05) in the CPSII-NC cohort. The risk for glioma was increased for the Janus cohort among individuals with sag-1 surface antigens (OR, 1.79; 95% CI, 1.02-3.14; P =.04) and risk for glioblastoma was similarly increased among those with sag-1 surface antigens (OR, 2.56; 95% CI, 1.18-5.52; P =.02).

Stratified by time of infection, those who were diagnosed with glioma more than 18 years after donating blood had reduced risk for glioma on the basis of T gondii infection (OR, 1.00; 95% CI, 0.49-2.05) compared with those diagnosed between 13 and 18 years (OR, 1.15; 95% CI, 0.55-2.43) or 5 to 13 years (OR, 2.50; 95% CI, 0.97-6.44; P =.06) after blood assessment.

The study was limited by its small sample sizes and limited ethnic diversity as the majority of participants were White.

The data indicate there may be some association between gliomas and T gondii infection. Further studies among larger, more diverse cohorts are needed to verify this association and to assess the mechanism of increased risk.

Reference

Hodge J M, Coghill A E, Kim Y, et al. Toxoplasma gondii infection and the risk of adult glioma in two prospective studies. Int J Cancer. Published online January 11, 2021. doi:10.1002/ijc.33443