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INTRODUCTION: Relationships and interplay of an infection burden (IB) and periodontal pathogens or periodontal disease (Pd) markers with Alzheimer's disease (AD) and all-cause dementia among US adults were examined. METHODS: Less than or equal to 2997 participants from the National Health and Nutrition Survey III were linked to CMS-Medicare [≥45 years (1988-1994); ≤30 years follow-up]. RESULTS: Hepatitis C (hazard ratio = 3.33, p = 0.004) and herpes simplex virus 2 were strongly associated with greater all-cause dementia risk. Porphyromonas gingivalis and Streptococcus oralis were associated with greater AD risk at higher IB. The red-green periodontal pathogen cluster coupled with higher IB count increased the risk of all-cause dementia among minority racial groups. Pocket probing depth associated with dementia risk at lower IB in the overall sample. DISCUSSION: Select viruses and bacteria were associated with all-cause and AD dementia, while the IB interacted with Pd markers in relation to these outcomes. HIGHLIGHTS: Interplay of infection burden (IB) and periodontal disease with dementia was tested. ≤2997 participants from NHANES III were linked to Medicare. Hepatitis C and herpes simplex virus 2 strongly associated with dementia risk. Tetanus sero-positivity increased Alzheimer's disease (AD) risk. Porphyromonas gingivalis and Streptococcus oralis associated with AD at higher IB. Red-green periodontal cluster at high IB, increased dementia in racial minorities. Pocket probing depth associated with dementia risk at lower IB.
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Neurodegenerative disease is a major global health problem with 150 million people predicted to have dementia by 2050. Genetic factors, environmental factors, demographics, and some diseases have been associated with dementia. In addition to associations between diseases such as hypertension and cerebrovascular disease and dementia, emerging findings associate some psychiatric disorders with incident dementia. Because of the high and increasing global prevalence of dementia and the high worldwide prevalence of psychiatric disorders, the primary objective of this narrative review was to evaluate published findings that evaluate the association between bipolar disorder, depression, anxiety, post-traumatic stress disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorder, schizophrenia and other psychosis syndromes, and personality disorders and personality traits and incident dementia. Here, we highlight findings indicating possible associations between these psychiatric disorders and subsequent dementia and suggest that some psychiatric disorders may be risk factors for incident dementia. Further research, including more large longitudinal studies and additional meta-analyses, however, is needed to better characterize the associations between psychiatric disorders and incident dementia, to identify possible mechanisms for these putative associations, and to identify risk factors within psychiatric disorders that predispose some people with a psychiatric disorder but not others to subsequent dementia. Additional important questions concern how the treatment of psychiatric disorders might affect the risk of incident dementia.
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A common infection, human cytomegalovirus (HCMV) has been associated with a variety of human diseases, including cardiovascular disease and possibly certain cancers. HCMV has also been associated with cognitive, psychiatric, and neurological conditions. Children with congenital or early-life HCMV are at risk for microcephaly, cerebral palsy, and sensorineural hearing loss, although in many cases sensorineural loss may resolve. In addition, HCMV can be associated with neurodevelopmental impairment, which may improve with time. In young, middle-aged, and older adults, HCMV has been adversely associated with cognitive function in some but not in all studies. Research has linked HCMV to Alzheimer's and vascular dementia, but again not all findings consistently support these associations. In addition, HCMV has been associated with depressive disorder, bipolar disorder, anxiety, and autism-spectrum disorder, although the available findings are likewise inconsistent. Given associations between HCMV and a variety of neurocognitive and neuropsychiatric disorders, additional research investigating reasons for the considerable inconsistencies in the currently available findings is needed. Additional meta-analyses and more longitudinal studies are needed as well. Research into the effects of antiviral medication on cognitive and neurological outcomes and continued efforts in vaccine development have potential to lower the neurocognitive, neuropsychiatric, and neurological burden of HCMV infection.
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Persistent infections, whether viral, bacterial or parasitic, including Helicobacter pylori infection, have been implicated in non-communicable diseases, including dementia and other neurodegenerative diseases. In this cross-sectional study, data on 635 cognitively normal participants from the UK Biobank study (2006-21, age range: 40-70 years) were used to examine whether H. pylori seropositivity (e.g. presence of antibodies), serointensities of five H. pylori antigens and a measure of total persistent infection burden were associated with selected brain volumetric structural MRI (total, white, grey matter, frontal grey matter (left/right), white matter hyperintensity as percent intracranial volume and bi-lateral sub-cortical volumes) and diffusion-weighted MRI measures (global and tract-specific bi-lateral fractional anisotropy and mean diffusivity), after an average 9-10 years of lag time. Persistent infection burden was calculated as a cumulative score of seropositivity for over 20 different pathogens. Multivariable-adjusted linear regression analyses were conducted, whereby selected potential confounders (all measures) and intracranial volume (sub-cortical volumes) were adjusted, with stratification by Alzheimer's disease polygenic risk score tertile when exposures were H. pylori antigen serointensities. Type I error was adjusted to 0.007. We report little evidence of an association between H. pylori seropositivity and persistent infection burden with various volumetric outcomes (P > 0.007, from multivariable regression models), unlike previously reported in past research. However, H. pylori antigen serointensities, particularly immunoglobulin G against the vacuolating cytotoxin A, GroEL and outer membrane protein antigens, were associated with poorer tract-specific white matter integrity (P < 0.007), with outer membrane protein serointensity linked to worse outcomes in cognition-related tracts such as the external capsule, the anterior limb of the internal capsule and the cingulum, specifically at low Alzheimer's disease polygenic risk. Vacuolating cytotoxin A serointensity was associated with greater white matter hyperintensity volume among individuals with mid-level Alzheimer's disease polygenic risk, while among individuals with the highest Alzheimer's disease polygenic risk, the urease serointensity was consistently associated with reduced bi-lateral caudate volumes and the vacuolating cytotoxin A serointensity was linked to reduced right putamen volume (P < 0.007). Outer membrane protein and urease were associated with larger sub-cortical volumes (e.g. left putamen and right nucleus accumbens) at middle Alzheimer's disease polygenic risk levels (P < 0.007). Our results shed light on the relationship between H. pylori seropositivity, H. pylori antigen levels and persistent infection burden with brain volumetric structural measures. These data are important given the links between infectious agents and neurodegenerative diseases, including Alzheimer's disease, and can be used for the development of drugs and preventive interventions that would reduce the burden of those diseases.
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Introduction Hospital-acquired infections (HAIs) after stroke are associated with additional morbidity and mortality, but whether HAIs increase long-term cognitive decline in stroke patients is unknown. We hypothesized that older adults with incident stroke with HAI experience faster cognitive decline than those having stroke without HAI and those without stroke. Methods We performed a longitudinal analysis in the population-based prospective Cardiovascular Health Study. Medicare-eligible participants aged >65 years with and without incident stroke had cognition assessed annually. HAIs were assessed by hospital discharge codes. Global cognitive function was assessed annually by Modified Mini-Mental State Examination (3MSE) and executive function by Digit Symbol Substitution Test (DSST). We used linear mixed models to estimate the mean decline and 95% confidence intervals (95% CI) for 3MSE and DSST scores by incident stroke and HAI status, adjusted for demographics and vascular risk factors. Results Among 5,443 participants >65 years without previous history of stroke, 393 participants had stroke with HAI (SI), 766 had a stroke only (SO), and 4,284 had no stroke (NS) throughout a maximum 9-year follow-up. For 3MSE, compared with NS participants, SO participants had a similar adjusted mean decline (additional 0.08 points/year, 95%CI -0.15, 0.31), while SI participants had a more rapid decline (additional 0.28 points/year, 95%CI 0.16, 0.40). Adjusted mean decline was 0.20 points/year faster (95%CI -0.05, 0.45) among SI than SO participants. For DSST, compared with NS participants, SO participants had a faster adjusted mean decline (additional 0.17 points/year (95%CI 0.003, 0.33), as did SI participants (additional 0.27 points/year (95%CI 0.19, 0.35). Conclusion Stroke, when accompanied by HAI, leads to a faster long-term decline in cognitive ability than in those without stroke. The clinical and public health implications of the effect of infection on post-stroke cognitive decline warrant further attention.
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BACKGROUND: Cardiovascular health is associated with brain magnetic resonance imaging (MRI) markers of pathology and infections may modulate this association. METHODS: Using data from 38,803 adults (aged 40-70 years) and followed-up for 5-15 years, we tested associations of prevalent total (47.5%) and hospital-treated infection burden (9.7%) with brain structural and diffusion-weighted MRI (i.e., sMRI and dMRI, respectively) common in dementia phenome. Poor white matter tissue integrity was operationalized with lower global and tract-specific fractional anisotropy (FA) and higher mean diffusivity (MD). Volumetric sMRI outcomes included total, gray matter (GM), white matter (WM), frontal bilateral GM, white matter hyperintensity (WMH), and selected based on previous associations with dementia. Cardiovascular health was measured with Life's Essential 8 score (LE8) converted to tertiles. Multiple linear regression models were used, adjusting for intracranial volumes (ICV) for subcortical structures, and for demographic, socio-economic, and the Alzheimer's Disease polygenic risk score for all outcomes, among potential confounders. RESULTS: In fully adjusted models, hospital-treated infections were inversely related to GM (ß ± SE: -1042 ± 379, p = 0.006) and directly related to WMH as percent of ICV (Loge transformed) (ß ± SE:+0.026 ± 0.007, p < 0.001). Both total and hospital-treated infections were associated with poor WMI, while the latter was inversely related to FA within the lowest LE8 tertile (ß ± SE:-0.0011 ± 0.0003, p < 0.001, PLE8×IB < 0.05), a pattern detected for GM, Right Frontal GM, left accumbens and left hippocampus volumes. Within the uppermost LE8 tertile, total infection burden was linked to smaller right amygdala while being associated with larger left frontal GM and right putamen volumes, in the overall sample. Within that uppermost tertile of LE8, caudate volumes were also positively associated with hospital-treated infections. CONCLUSIONS: Hospital-treated infections had more consistent deleterious effects on volumetric and white matter integrity brain neuroimaging outcomes compared with total infectious burden, particularly in poorer cardiovascular health groups. Further studies are needed in comparable populations, including longitudinal studies with multiple repeats on neuroimaging markers.
Subject(s)
Dementia , White Matter , Adult , Humans , White Matter/diagnostic imaging , White Matter/pathology , Diffusion Tensor Imaging/methods , Biological Specimen Banks , Brain/diagnostic imaging , Brain/pathology , Magnetic Resonance Imaging/methods , Gray Matter/diagnostic imaging , Gray Matter/pathology , United KingdomABSTRACT
A decline in intellectual functioning (intelligence quotient [IQ]) is often observed following more severe forms of traumatic brain injury (TBI) and is a useful index for long-term outcome. Identifying brain correlates of IQ can serve to inform developmental trajectories of behavior in this population. Using magnetic resonance imaging (MRI), we examined the relationship between intellectual abilities and patterns of cortical thickness in children with a history of TBI or with orthopedic injury (OI) in the chronic phase of injury recovery. Participants were 47 children with OI and 58 children with TBI, with TBI severity ranging from complicated-mild to severe. Ages ranged from 8 to 14 years old, with an average age of 10.47 years, and an injury-to-test range of â¼1-5 years. The groups did not differ in age or sex. The intellectual ability estimate (full-scale [FS]IQ-2) was derived from a two-form (Vocabulary and Matrix Reasoning subtests) Wechsler Abbreviated Scale of Intelligence (WASI). MRI data were processed using the FreeSurfer toolkit and harmonized across data collection sites using neuroComBat procedures, while holding demographic features (i.e., sex, socioeconomic status [SES]), TBI status, and FSIQ-2 constant. Separate general linear models per group (TBI and OI) and a single interaction model with all participants were conducted with all significant results withstanding correction for multiple comparisons via permutation testing. Intellectual ability was higher (p < 0.001) in the OI group (FSIQ-2 = 110.81) than in the TBI group (FSIQ-2 = 99.81). In children with OI, bi-hemispheric regions, including the right pre-central gyrus and precuneus and bilateral inferior temporal and left occipital areas were related to IQ, such that higher IQ was associated with thicker cortex in these regions. In contrast, only cortical thickness in the right pre-central gyrus and bilateral cuneus positively related to IQ in children with TBI. Significant interaction effects were found in the bilateral temporal, parietal, and occipital lobes and left frontal regions, indicating that the relationship between IQ and cortical thickness differed between groups in these regions. Changes in cortical associations with IQ after TBI may reflect direct injury effects and/or adaptation in cortical structure and intellectual functioning, particularly in the bilateral posterior parietal and inferior temporal regions. This suggests that the substrates of intellectual ability are particularly susceptible to acquired injury in the integrative association cortex. Longitudinal work is needed to account for normal developmental changes and to investigate how cortical thickness and intellectual functioning and their association change over time following TBI. Improved understanding of how TBI-related cortical thickness alterations relate to cognitive outcome could lead to improved predictions of outcome following brain injury.
Subject(s)
Brain Injuries, Traumatic , Brain Injuries , Humans , Child , Infant , Child, Preschool , Adolescent , Brain Injuries, Traumatic/complications , Brain Injuries, Traumatic/diagnostic imaging , Brain Injuries, Traumatic/pathology , Brain/pathology , Cognition , Brain Injuries/complications , Magnetic Resonance Imaging/methodsABSTRACT
Associated with gastritis, peptic-ulcer disease, and gastric carcinoma, Helicobacter pylori (H. pylori) also has been associated with decreased cognitive function and dementia. In this study, we used data from the UK Biobank to further examine associations between H. pylori seropositivity and serointensity and performance on several cognitive tasks in adults 40 to 70 years of age (M = 55.3, SD = 8.1). In these analyses, H. pylori seropositivity (i.e., either positive or negative for H. pylori) and serointensity (concentration of antibodies against H. pylori antigens) in adjusted models were associated with worse function on tasks of Numeric memory, Reasoning, and errors on the Pairs matching test but better function on the Tower rearrangement task. Together, these findings suggest that H. pylori seropositivity and serointensity might be associated with worse cognitive function in this age group.
Subject(s)
Helicobacter Infections , Helicobacter pylori , Adult , Humans , Helicobacter Infections/pathology , Antibodies, Bacterial , Cognition , United Kingdom/epidemiologyABSTRACT
Type-1 diabetes, an autoimmune disease characterized by damage to pancreatic insulin-producing beta cells, is associated with adverse renal, retinal, cardiovascular, and cognitive outcomes, possibly including dementia. Moreover, the protozoal parasite Toxoplasma gondii has been associated with type-1 diabetes. To better characterize the association between type-1 diabetes and Toxoplasma gondii infection, we conducted a systematic review and meta-analysis of published studies that evaluated the relationship between type-1 diabetes and Toxoplasma gondii infection. A random-effects model based on nine primary studies (total number of participants = 2655) that met our inclusion criteria demonstrated a pooled odds ratio of 2.45 (95% confidence interval, 0.91-6.61). Removing one outlying study increased the pooled odds ratio to 3.38 (95% confidence interval, 2.09-5.48). These findings suggest that Toxoplasma gondii infection might be positively associated with type-1 diabetes, although more research is needed to better characterize this association. Additional research is required to determine whether changes in immune function due to type-1 diabetes increase the risk of infection with Toxoplasma gondii, infection with Toxoplasma gondii increases the risk of type-1 diabetes, or both processes occur.
Subject(s)
Diabetes Mellitus, Type 1 , Toxoplasma , Toxoplasmosis , Humans , Risk Factors , Diabetes Mellitus, Type 1/complications , Odds Ratio , Seroepidemiologic StudiesABSTRACT
Children experiencing epileptic seizures (ES) and children experiencing non-epileptic seizures (NES) may experience deficits in both executive functioning and in social skills, but little research has examined differences in executive functioning between the two groups and no studies have examined the relationship between executive functioning and social skills in pediatric ES and NES groups. The purposes of this study were to determine if ES/NES group differences exist for executive functioning and to determine if executive functioning was related to social skills in these groups. Children (N = 43) were recruited from epilepsy monitoring units (EMU) at Primary Children's Medical Center and Phoenix Children's Hospital. The NES group consisted of 15 participants (67 % female, M age at test = 12.62, SD = 3.33), and the ES group consisted of 28 participants (50 % female, M age at testing = 11.79, SD = 3.12). Parents and children completed the Social Skills Improvement System (SSIS) Rating Scales, and the Behavior Rating Inventory of Executive Function (BRIEF). No significant differences on measures of executive functioning were observed between ES and NES groups. Parent reports of poorer behavioral regulation correlated to parent reports of poorer social skills in both groups, but neither parent nor child ratings of executive functioning correlated with child-reported social skills. This finding suggests there may be differences between parent and child self-observations of executive functioning and social skills in both NES and ES groups. Limitations to this study and directions for future research are discussed.
Subject(s)
Epilepsy , Executive Function , Humans , Child , Female , Male , Executive Function/physiology , Social Skills , SeizuresABSTRACT
The nematodes Toxocara canis (Werner, 1782) and Toxocara cati (Schrank, 1788) have been associated with worse human cognitive function in children and middle-aged adults. In this study, we sought to determine the association between Toxocara seropositivity and serointensity determined by detection of IgG antibodies against the Toxocara antigen recombinant Tc-CTL-1 and cognitive function in older adults, including approximately 1,350 observations from the 2013-2014 National Health and Nutrition Examination Survey. Mean fluorescence intensity was used to quantify IgG antibodies against the Toxocara recombinant Tc-CTL-1 antigen, and respondents were considered positive at values greater than 23.1. In adjusted models from sample sizes ranging from 1,274 to 1,288 depending on the individual cognitive task, we found that Toxocara seropositivity was associated with worse performance on the animal-fluency task (b = -1.245, 95% CI: -2.392 to -0.099, P< 0.05) and the digit-symbol coding task (b = -5.159, 95% CI: -8.337 to -1.980, P< 0.001). Toxocara serointensity assessed using log-transformed mean fluorescence intensity as a continuous variable was associated with worse performance on the digit-symbol coding task (b = -1.880, 95% CI: -2.976 to -0.783, P < 0.001). There were no significant associations with tasks assessing memory. Further, age modified the association between Toxocara and cognitive function, although sex, educational attainment, and income did not. These findings suggest that Toxocara might be associated with deficits in executive function and processing speed in older U.S. adults, although additional research is required to better describe cognitive function in older adults who are seropositive for Toxocara spp.
Subject(s)
Toxocariasis , Animals , Cognition , Immunoglobulin G , Nutrition Surveys , Toxocara , Toxocariasis/complications , Toxocariasis/diagnosis , Toxocariasis/epidemiologyABSTRACT
Infecting much of the world's population, the herpesviridae virus cytomegalovirus has been associated with lower cognitive function in some but not all studies. In this study, we further investigate associations between cytomegalovirus and cognitive function in a community-based sample of adults aged 40 to 70 years (M = 55.3; SD = 8.1) from the United Kingdom. Adjusted multiple-regression modeling showed no significant associations between cytomegalovirus and performance on nine cognitive tasks. Further, in adjusted interaction models, age, sex, educational attainment, and income did not moderate associations between cytomegalovirus and cognitive function. In this community-based adult sample, cytomegalovirus was not associated with cognitive function.
Subject(s)
Cognition , Cytomegalovirus , Adult , Educational Status , Humans , United Kingdom/epidemiologyABSTRACT
Several viral, bacterial, and parasitic diseases have been associated with cognitive function and neuropsychiatric outcomes in humans, including human T-cell lymphotropic virus 1 (HTLV-1). In this study, we sought to further generalize previously reported associations of cognitive function and depression with HTLV-1 seropositivity and serointensity using a community-based sample of adults aged approximately 40 to 70 years (mean = 55.3 years) from the United Kingdom. In this sample, the results of adjusted linear regression models showed no associations of HTLV-1 seropositivity or serointensity with reasoning, pairs-matching, or reaction-time cognitive tasks or with depression. In addition, neither age, sex, educational attainment, nor income moderated associations of HTLV-1 seropositivity or serointensity with cognitive function or depression. In this middle-aged to older middle-aged adult community sample, HTLV-1 seropositivity and serointensity do not appear to be associated with reasoning, pairs-matching, and reaction-time tasks or with depression.
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Infecting approximately one-third of the world's population, the neurotropic protozoan Toxoplasma gondii has been associated with cognition and several neuropsychiatric diseases including schizophrenia and bipolar disorder. Findings have been mixed, however, about the relationship between Toxoplasma gondii and depression, with some studies reporting positive associations and others finding no associations. To further investigate the association between Toxoplasma gondii and depression, we used data from the UK Biobank and the National Health and Examination Survey (NHANES). Results from adjusted multiple-regression modeling showed no significant associations between Toxoplasma gondii and depression in either the UK Biobank or NHANES datasets. Further, we found no significant interactions between Toxoplasma gondii and age, sex, educational attainment, and income in either dataset that affected the association between Toxoplasma gondii and depression. These results from two community-based datasets suggest that in these samples, Toxoplasma gondii is not associated with depression. Differences between our findings and other findings showing an association between Toxoplasma gondii and depression could be due to several factors including differences in socioeconomic variables, differences in Toxoplasma gondii strain, and use of different covariates in statistical modeling.
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OBJECTIVE: Hydrocephalus can impact all areas of health, including physical, cognitive, and social-emotional functioning. The social-emotional health of children who have had surgery for hydrocephalus is not well characterized. In this study, the authors sought to examine social-emotional functioning using the Behavior Assessment System for Children, Third Edition (BASC-3) and the Hydrocephalus Outcome Questionnaire (HOQ) in 66 children aged 5 to 17 years. METHODS: Caregivers of pediatric patients with hydrocephalus completed the BASC-3 and the HOQ. BASC-3 internalizing, externalizing, and executive functioning caregiver-reported scores were compared with the BASC-3 normative sample using one-sample t-tests to evaluate overall social-emotional functioning. BASC-3 scores were correlated with the social-emotional domain of the HOQ using Pearson's r to determine if the HOQ accurately captured the social-emotional functioning of children with hydrocephalus in a neurosurgery setting. BASC-3 and HOQ scores of children with different etiologies of hydrocephalus were compared using the Kruskal-Wallis one-way analysis of variance to determine if differences existed between the following etiologies: intraventricular hemorrhage secondary to prematurity, myelomeningocele, communicating congenital hydrocephalus, aqueductal stenosis, or other. RESULTS: Children with hydrocephalus of all etiologies had more difficulties with social-emotional functioning compared with normative populations. Children with different hydrocephalus etiologies differed in executive functioning and overall HOQ scores but not in internalizing symptoms, externalizing symptoms, or social-emotional HOQ scores. The social-emotional domain of the HOQ correlated more strongly with the BASC-3 than did the physical and cognitive domains. CONCLUSIONS: These results have provided evidence that children who have had surgery for hydrocephalus may be at increased risk of social-emotional and behavioral difficulties, but etiology may not be particularly helpful in predicting what kinds or degree of difficulty. The results of this study also support the convergent and divergent validity of the social-emotional domain of the HOQ.
Subject(s)
Hydrocephalus/psychology , Hydrocephalus/surgery , Adolescent , Caregivers/psychology , Child , Child, Preschool , Female , Humans , Hydrocephalus/epidemiology , Male , Prospective Studies , Quality of Life , Surveys and QuestionnairesABSTRACT
The intracellular protozoal parasite Toxoplasma gondii has been associated with worsened cognitive function in animal models and in humans. Despite these associations, the mechanisms by which Toxoplasma gondii might affect cognitive function remain unknown, although Toxoplasma gondii does produce physiologically active intraneuronal cysts and appears to affect dopamine synthesis. Using data from the UK Biobank, we sought to determine whether Toxoplasma gondii is associated with decreased prefrontal, hippocampal, and thalamic gray-matter volumes and with decreased total gray-matter and total white-matter volumes in an adult community-based sample. The results from adjusted multivariable regression modelling showed no associations between Toxoplasma gondii and prefrontal, hippocampal, and thalamic brain gray-matter volumes. In contrast, natural-log transformed antibody levels against the Toxoplasma gondii p22 (b = -3960, 95-percent confidence interval, -6536 to -1383, p < .01) and sag1 (b = -4863, 95-percent confidence interval, -8301 to -1425, p < .01) antigens were associated with smaller total gray-matter volume, as was the mean of natural-log transformed p22 and sag1 titers (b = -6141, 95-percent confidence interval, -9886 to -2397, p < .01). There were no associations between any of the measures of Toxoplasma gondii and total white-matter volume. These findings suggest that Toxoplasma gondii might be associated with decreased total gray-matter in middle-aged and older middle-aged adults in a community-based sample from the United Kingdom.
Subject(s)
Brain/anatomy & histology , Brain/parasitology , Toxoplasma/physiology , Adult , Brain/diagnostic imaging , Brain/physiology , Cognition , Cross-Sectional Studies , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Organ SizeABSTRACT
Infecting approximately one-third of the world's human population, Toxoplasma gondii has been associated with cognitive function. Here, we sought to further characterize the association between Toxoplasma gondii and cognitive function in a community sample of adults aged approximately 40 to70 years. Using adjusted linear regression models, we found associations of Toxoplasma gondii seropositivity with worse reasoning (b = -.192, p < .05) and matrix pattern completion (b = -.681, p < .01), of higher anti-Toxoplasma gondii p22 antibody levels with worse reasoning (b = -.078, p < .01) and slower Trails (numeric) performance (b = 5.962, p < .05), of higher anti-Toxoplasma gondii sag1 levels with worse reasoning (b = -.081, p < .05) and worse matrix pattern completion (b = -.217, p < .05), and of higher mean of the anti-Toxoplasma gondii p22 and sag1 levels with worse reasoning (b = -.112, p < .05), slower Trails (numeric) performance (b = 9.195, p < .05), and worse matrix pattern completion (b = -.245, p < .05). Neither age nor educational attainment moderated associations between the measures of Toxoplasma gondii seropositivity or serointensity. Sex, however, moderated the association between the sag1 titer and digit-symbol substitution and the association between the mean of the p22 and sag1 levels and digit-symbol substitution, and income moderated the association between Toxoplasma gondii seropositivity and numeric memory and the association between the p22 level and symbol-digit substitution. Based on the available neuropsychological tasks in this study, Toxoplasma gondii seropositivity and serointensity were associated with some aspects of poorer executive function in adults.
Subject(s)
Cognition , Toxoplasma/isolation & purification , Toxoplasmosis/physiopathology , Adult , Aged , Antibodies, Protozoan/blood , Executive Function , Female , Humans , Immunoglobulin G/blood , Linear Models , Male , Middle Aged , Toxoplasmosis/blood , United KingdomABSTRACT
Caused by the neuroinvasive nematodes Toxocara canis and Toxocara cati, human toxocariasis has a worldwide distribution with seroprevalence in humans associated with low socioeconomic status and low educational attainment. Third-stage Toxocara larvae can invade human tissues, including the brain and spine, where they can result in encephalitis, meningitis, and inflammation. Toxocara infection in animal models has been associated with cognitive and behavioural changes. In humans, preliminary cross-sectional research suggests that Toxocara seropositivity is associated with worse cognitive function in children and adults. Additional preliminary cross-sectional findings suggest associations between Toxocara seropositivity and neuropsychiatric function, including schizophrenia and neurologic conditions such as epilepsy. Given the widespread distribution of human toxocariasis and early evidence suggesting that it can be associated with cognitive and neuropsychiatric function in humans, additional research regarding the effects of toxocariasis on the human brain is required.
Subject(s)
Central Nervous System Parasitic Infections/psychology , Cognition , Mental Disorders/parasitology , Toxocariasis/psychology , Adult , Animals , Central Nervous System Parasitic Infections/complications , Child , Humans , Mental Disorders/etiology , Toxocara , Toxocariasis/complicationsABSTRACT
BACKGROUND: Air pollution has been associated with cognitive function and brain volume. While most previous research has examined the association between air pollution and brain volume in cortical structures or total brain volume, less research has investigated associations between exposure to air pollution and subcortical structures, including the thalamus. Further, the few available previous studies investigating associations between air pollution and thalamic volume have shown mixed results. METHODS: In this study, we evaluated the association between PM2.5, PM2.5-10, PM10, nitrogen dioxide, and nitrogen oxides and volume of the thalamus in adults using the UK Biobank resource, a large community-based sample, while adjusting for multiple covariates that could confound an association between air pollution and thalamic volume. RESULTS: In adjusted models, the left but not right thalamus volume was significantly inversely associated with PM2.5-10, although there were no significant associations between PM2.5, PM10, nitrogen dioxide, and nitrogen oxides with either left or right thalamic volumes. In addition, interactions between age and PM2.5-10 and PM10 were inversely associated with thalamic volume, such that thalamic volume in older people appeared more vulnerable to the adverse effects of PM2.5-10 and PM10, and interactions between educational attainment and PM2.5, nitrogen dioxide, and nitrogen oxides and between self-rated health and PM2.5-10 were positively associated with thalamic volume, such that higher educational attainment and better self-rated health appeared protective against the adverse effects of air pollution on the thalamus. CONCLUSION: These findings suggest a possible association between thalamic volume and air pollution particularly in older people and in people with comparatively low educational attainment at levels of air pollution found in the United Kingdom.
Subject(s)
Air Pollution/adverse effects , Environmental Exposure/adverse effects , Thalamus/anatomy & histology , Thalamus/drug effects , Adult , Aged , Cross-Sectional Studies , Humans , Middle AgedABSTRACT
Associated with numerous cognitive and behavioral functions and with several diseases, the prefrontal cortex is vulnerable to environmental insult. Among other factors, toxins in air pollution have been associated with damage to the prefrontal cortex in children and older adults. We used data from the UK Biobank to assess further associations between an array of toxins in air pollution and gray matter in the prefrontal cortex including the left and right frontal poles, left and right superior frontal gyri, left and right frontal medial cortex, left and right orbitofrontal cortex, and left and right frontal opercula, using multivariate models adjusted for covariates that possibly could confound the association between air pollution and volume of prefrontal gray matter. The results showed inverse associations between PM 2.5, PM 10, and nitrogen oxides and prefrontal volume in models adjusted for age, sex, education, socioeconomic status, race-ethnicity, self-rated overall health, body mass index, total brain volume, smoking status, and alcohol use frequency. Education appeared to moderate the association between air pollution and prefrontal volume. The data in these analyses came from regions whose mean PM 2.5 was near the upper limit and whose mean PM 10 was under those recommended by the World Health Organization. These findings suggest that comparatively low levels of air pollution might be associated with reduced volume of the prefrontal cortex.