The Association of Toxoplasma gondii IgG Antibody and Chronic Kidney Disease Biomarkers

Association of Combined Per- and Polyfluoroalkyl Substances and Metals with Chronic Kidney Disease

Background: Exposure to environmental pollutants such as metals and Per- and Polyfluoroalkyl Substances (PFAS) has become common and increasingly associated with a decrease in the estimated Glomerular Filtration Rate (eGFR), which is a marker often used to measure chronic kidney disease (CKD). However, there are limited studies involving the use of both eGFR and the urine albumin creatinine ratio (uACR), which are more comprehensive markers to determine the presence of CKD and the complexity of pollutant exposures and response interactions, especially for combined metals and PFAS, which has not been comprehensively elucidated. Objective: This study aims to assess the individual and combined effects of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), Cadmium (Cd), Mercury (Hg), and Lead (Pb) exposure on CKD using data from the National Health and Nutritional Examination Survey (NHANES) 2017-2018. Methods: We employed the use of bivariate logistic regression and Bayesian Kernel Machine Regression (BKMR) in our analysis of the data. Results: Logistic regression results revealed a positive association between PFOA and CKD. Our BKMR analysis revealed a non-linear and bi-phasic relationship between the metal exposures and CKD. In our univariate exposure-response function plot, Cd and Hg exhibited a U and N-shaped interaction, which indicated a non-linear and non-additive relationship with both low and high exposures associated with CKD. In addition, the bivariate exposure-response function between two exposures in a mixture revealed that Cd had a U-shaped relationship with CKD at different quantiles of Pb, Hg, PFOA, and PFOS, indicating that both low and high levels of Cd is associated with CKD, implying a non-linear and complex biological interaction. Hg's interaction plot demonstrated a N-shaped association across all quantiles of Cd, with the 75th quantile of Pb and the 50th and 75th quantiles of PFOA and PFOS. Furthermore, the PIP results underscored Cd's consistent association with CKD (PIP = 1.000) followed by Hg's (PIP = 0.9984), then PFOA and PFOS with a closely related PIP of 0.7880 and 0.7604, respectively, and finally Pb (PIP = 0.6940), contributing the least among the five environmental pollutants on CKD, though significant. Conclusions: Our findings revealed that exposure to environmental pollutants, particularly Hg and Cd, are associated with CKD. These findings highlight the need for public health interventions and strategies to mitigate the cumulative effect of PFAS and metal exposure and elucidate the significance of utilizing advanced statistical methods and tools to understand the impact of environmental pollutants on human health. Further research is needed to understand the mechanistic pathways of PFAS and metal-induced kidney injury and CKD, and longitudinal studies are required to ascertain the long-term impact of these environmental exposures.

Toxoplasma gondii seropositivity and cognitive functioning in older adults: an analysis of cross-sectional data of the National Health and Nutrition Examination Survey 2011-2014

OBJECTIVES

This study sought to examine the relationship between Toxoplasma gondii seropositivity and cognitive function in older adults.

DESIGN

An observational cross-sectional study.

SETTING

The National Health and Nutrition Examination Survey (NHANES) study took place at participants' homes and mobile examination centres.

PARTICIPANTS

A total of 2956 older adults aged 60 and above from the NHANES from 2011 to 2014 were included in the study. Exposure of interest: participants had serum Toxoplasma gondii antibody analysed in the laboratory. A value>33 IU/mL was categorised as seropositive for Toxoplasma gondii infection; <27 IU/mL was categorised as seronegative for Toxoplasma gondii infection.

PRIMARY AND SECONDARY OUTCOME MEASURES

Cognitive tests included the Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL) for immediate and delayed memory, the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST).

RESULTS

About half of the 2956 participants (mean age 70.0) were female (51.0%), non-Hispanic White (48.3%), and completed some college or above (48.3%). A total of 703 participants were positive for Toxoplasma gondii infection (23.8%). Adjusted linear regression showed that compared with participants with negative Toxoplasma gondii infection, those with positive Toxoplasma gondii infection had lower CERAD-WL immediate memory (beta (β) -0.16, 95% CI -0.25 to -0.07), CERAD-WL delayed memory (β -0.15, 95% CI -0.24 to -0.06), AFT (β -0.15, 95% CI -0.24 to -0.06), DSST (β -0.34, 95% CI -0.43 to -0.26), and global cognition (β -0.24, 95% CI -0.32 to -0.16) z-scores after controlling for the covariates.

CONCLUSIONS

Toxoplasma gondii seropositivity is associated with worse immediate and delayed verbal learning, language proficiency, executive functioning, processing speed, sustained attention, working memory, as well as global cognition in older adults. Public health measures aiming at preventing Toxoplasma gondii infection may help preserve cognitive functioning in older adults.

The Association of Toxoplasma gondii with the Combination of Cardiovascular Disease, Chronic Kidney Disease, or Chronic Liver Disease: A Preliminary Study

Toxoplasma gondii is a protozoan parasite widespread worldwide, with over 40 million individuals in the United States. It may infect vital organs such as the heart, kidneys, and liver, resulting in chronic infections. The main objective of this study is to investigate the association of Toxoplasma infection with the combination of cardiovascular disease, chronic kidney disease (CKD), or chronic liver disease (CLD). The National Health and Nutrition Examination Survey (NHANES 2009-2010) data were used, and the association of infection with chronic disease was assessed with biomarkers and indexes using statistical modeling. The percentage of participants with a combination of CLD and CKD was higher among Toxoplasma positive participants compared to the negative participants (2.76 vs. 1.26). Furthermore, exposure to T. gondii may increase the odds of cardiovascular disease, CKD, or CLD, or vice versa.

The Association of Toxoplasma gondii IgG and Liver Injury in US Adults

Background: Toxoplasma gondii (T. gondii) is a ubiquitous obligatory intracellular parasite which infects over 40 million Americans and causes toxoplasmosis. Inside the human body, T. gondii can damage tissues and invade vital organs. Methods: This study evaluated the association of T. gondii infection and liver disease using data from the National Health and Nutrition Examination Survey (NHANES) 2009–2010, with a sample size of 3371 participants (age 20–80 years). Toxoplasma infection was determined by the level of T. gondii IgG antibody in serum samples. Liver disease was assessed by liver injury biomarkers and the Fatty Liver Index (US-FLI). The evaluation of the association between T. gondii infection and liver disease included the calculation of the Mantel–Haenszel risk ratio (RRMH), Rho-Scott chi-square bivariate analyses, design-based t-tests, and linear and logistic regression models which were adjusted for demographic and anthropometric covariates. Results: Mean levels of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were significantly more elevated in the T. gondii IgG-positive (IgG+) participants as compared to T. gondii-negative (IgG−) participants, p = 0.0435 and 0.0310, respectively. In linear regression analysis, exposure to T. gondii IgG+ had statistically significant positive associations with AST (p = 0.0211), alanine aminotransferase (ALT) (p = 0.0221), and gamma-glutamyl transferase (GGT) (p = 0.0258) after adjusting for BMI, age, gender, and race. T. gondii exposure was associated with an elevated relative risk of chronic liver disease (CLD) (RRMH = 1.26, 95% CI: 1.05–1.51). This association was more pronounced in certain occupations, such as construction, agriculture, forestry, and fishing, where Toxoplasma infection is more common (p = 0.0477). Moreover, Toxoplasma infection increased the odds of nonalcoholic fatty liver disease (NAFLD) (OR = 6.99, 95% CI = 1.85–26.32, p = 0.0237). Conclusion: T. gondii IgG+ antibody was significantly associated with liver injury biomarkers (ALT, AST, GGT, and ALP) and an increased risk of CLD and NAFLD. Moreover, the association of Toxoplasma with CLD was more evident in specific occupations where the prevalence of Toxoplasma was high. The findings of this study provide insight into utilizing liver biomarkers and US-FLI to assess the health complications of Toxoplasma when imaging tests are not accessible.

Organization of Post-Transplant Care and the 5-Year Outcomes of Kidney Transplantation

The outcomes of kidney transplantation depend on numerous factors and vary between transplant centers. The aim of this study is to assess the relationship between selected organizational factors, comorbidities, and patient and graft survival. This is a retrospective analysis of 438 renal transplant recipients (RTR) followed for 5 years. Patient and graft survival were evaluated in relation to hospitalization length, distance from the patient's residence to the transplant center, the frequency of outpatient transplant visits, and the number and type of comorbidities. Five-year patient and graft survival rates were 93% and 90%, respectively. We found significant associations of patient survival with the prevalence of pre-transplant diabetes, cardiovascular diseases, malignancies, the number of comorbidities, and the first post-transplant hospitalization length. The incidence of infections, cardiovascular diseases, and transplanted kidney diseases was 60%, 40%, and 33%, respectively. As many as 41% of RTR had unknown etiology of primary kidney disease. In conclusion, the organization of post-transplant care needs to be adapted to the multi-morbidity of contemporary RTR and include multi-specialist care, especially in the context of current problems related to the COVID-19pandemic. The high proportion of patients with undetermined etiology of their primary renal disease carry the risk for additional complications during their long-term follow-up.