The relationship between Toxoplasma gondii infection and mood disorders in the third National Health and Nutrition Survey.
BACKGROUND
Toxoplasma gondii (T. gondii) is a neurotropic protozoan parasite that causes persistent infection in humans. A substantial literature suggests that schizophrenia is associated with increased seroprevalence of T. gondii, but a possible link of the parasite with mood disorders has not been as thoroughly investigated.


METHODS
We examined the association of Toxoplasma-specific immunoglobulin G results with mood disorder outcomes in 7440 respondents from the third National Health and Nutrition Survey, which is a nationally representative sample of the United States noninstitutionalized civilian population. Regression models were adjusted for numerous potential confounders, including tobacco smoking and C-reactive protein levels.


RESULTS
No statistically significant associations were found between T. gondii seroprevalence and a history of major depression (n = 574; adjusted odds ratio [OR]: .8; 95% confidence interval [CI]: .5-1.2), severe major depression (n = 515; adjusted OR: .8; 95% CI: .6-1.2), dysthymia (n = 548; adjusted OR: 1.1; 95% CI: .7-1.8), or dysthymia with comorbid major depression (n = 242, adjusted OR: 1.2; 95% CI: .6-2.4), all p values were > .05, including analysis stratified by gender. However, there was a significant relationship between T. gondii seroprevalence and bipolar disorder type I for respondents in which both manic and major depression symptoms were reported (n = 41; adjusted OR: 2.4; 95% CI: 1.2-4.8; p < .05).


CONCLUSIONS
In a population-based sample, T. gondii seroprevalence is not elevated in unipolar mood disorders but is higher in a subset of respondents with a history of bipolar disorder type 1.
Department of Epidemiology, Emory University, Rollins School of Public Health, Atlanta, GA 30322, USA. bpearce@emory.edu
Brad D
BD
Pearce
Deanna
D
Kruszon-Moran
Jeffrey L
JL
Jones
D000293:Adolescent; D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis*; D003430:Cross-Sectional Studies; D006801:Humans; D019964:Mood Disorders / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D009749:Nutrition Surveys; D012044:Regression Analysis; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012907:Smoking; D012959:Socioeconomic Factors; D014123:Toxoplasmosis / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D002097:C-Reactive Protein