Background: Toxoplasma gondii (T. gondii) is a protozoan parasite with high prevalence worldwide. More than 40 million individuals in the United States carry this parasite. T. gondii infection causes toxoplasmosis, which is the leading cause of death associated with foodborne diseases in the United States. T. gondii infects humans through different routes, and it is capable of invading a wide range of tissues in the human body following the infection. Methods: The main objective of this study was to investigate the prevalence of T. gondii among adults in the United States and its association with cardiovascular health using data from the National Health and Nutrition Examination Survey (NHANES 2009-2010). Considering the limitation of studies investigating the relationship between T. gondii and cardiovascular biomarkers, this study was focused on assessing the association of T. gondii to nine cardiovascular biomarkers. First, those biomarkers were investigated individually using several statistical tests and models. Second, we developed an overall cardiovascular biomarker index (OCBI) from eight critical biomarkers to better explain the T. gondii potential cumulative effect on the cardiovascular system. These analyses were adjusted for demographic, behavioral, and anthropometric factors. Results:T. gondii IgG antibody-positive participants had significantly higher systolic blood pressure (p = 0.0022), triglycerides (p = 0.0399), C-reactive protein (p = 0.0422), gamma glutamyl transferase (p = 0.0400), and fasting glucose (p = 0.0213) than the negative participants. In addition, the positive participants had significantly lower high-density lipoprotein cholesterol (p = 0.0431) than the negative participants. Adjusting for age, T. gondii positive had a significant negative association with high-density lipoprotein cholesterol (p = 0.0026) and a significant positive association with low-density lipoprotein cholesterol (p = 0.0179), triglycerides (p = 0.0154), and gamma glutamyl transferase (p = 0.0026). With the exception of the low-density lipoprotein, these associations remained statistically significant when adjusting for demographic, behavioral, and anthropometric factors. These results potentially indicate the role of T. gondii in driving cardiovascular-related biomarkers toward dysfunction. The analysis also revealed a significant difference in the OCBI among positive and negative participants (p = 0.0020), with the (cumulative) odds of positive participants having a higher level of OCBI being 0.71 times lower than the odds for negative participants (OR = 0.29). Conclusions: Positive T. gondii IgG antibody was significantly associated with adverse effects on cardiovascular-related biomarkers, including systolic blood pressure, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and gamma glutamyl transferase. T. gondii-positive individuals were more likely to have a lower cardiovascular biomarkers index than the negative individuals. Finally, the prevalence of toxoplasmosis among U.S. adults was associated with demographic characteristics including age, ethnicity, country of birth, and occupation.
Keywords: T. gondii; Toxoplasma; biomarkers; cardiovascular disease; cardiovascular health.