Toxoplasma gondii (T. gondii) is an intracellular protozoan parasite that infects roughly a third of the world population. In an immunocompetent host, infection is generally chronic and asymptomatic, as the immune system keeps T. gondii confined to cysts and the intracellular space within the muscle and brain. Seropositivity has been linked to schizophrenia, car accidents, changes in personality, and more recently, suicidal attempts. Very recently, seroprevalence for 20 European countries was found to be associated with increased suicide rates. Although suicide rates were age-standardized, given that T. gondii seroprevalence increases with age and that the blood samples were drawn in women, we now retested in women only the association between suicide and T. gondii seropositivity, stratified by age. Simple correlations between ranked T. gondii seropositivity and suicide rate identified statistically significant relationships in women 60 years or older (p < 0.05); adjusting for GDP, the statistical significance expanded to include women 45 years and older. The strongest association was in the 60- to 74-year-old group where, after adjustment for GDP, the relationship (p = 0.007) resisted Bonferroni adjustment for multiple comparisons. In conclusion, the results suggest that a positive relationship between rates of infection with T. gondii and suicide is apparent in women of postmenopausal age. Prospective studies are necessary to further confirm this association predictively and to explore mechanisms mediating this relationship.
*University of Hawaii at Manoa, Honolulu, HI; †Richard Stockton College, Pomona, NJ; ‡National Centre for Register-Based Research, University of Aarhus, Aarhus, Denmark; and §Department of Epidemiology and Preventive Medicine, and ∥Mood and Anxiety Program, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD.
This study is supported by grants from the American Foundation for Suicide Prevention and the National Institutes of Health (R01MH074891), both to T. T. P.
Send reprint requests to Teodor T. Postolache, MD, Mood and Anxiety Program (MAP), Department of Psychiatry, University of Maryland School of Medicine, 685 West Baltimore St, MSTF Building Room 502, Baltimore, MD 21201.E-mail: firstname.lastname@example.org.