Early adverse childhood experiences and adolescent sleep outcomes.

BACKGROUND: Sleep is critical for physical, mental, and emotional health. This may be particularly true for adolescents experiencing rapid physiological changes. Relatively little is known about how adverse childhood experiences (ACEs) are implicated in adolescent experiences with sleep. OBJECTIVE: We use data (from the Future of Families and Child Wellbeing Study (FFCWS, n = 3444) to assess the relationship between early ACE exposure (by age 5) and various adolescent sleep outcomes. We anticipate that early ACEs will be associated with poor adolescent sleep outcomes. METHODS: FFCWS data includes survey responses from parents and/or primary caregivers and children at birth and approximately one, three, five, nine, and 15 years later. The FFCWS oversampled unmarried parents with low educational attainment, income, and from marginalized racial-ethnic groups. Models of sleep outcomes included ordinary least squares, Poisson, negative binomial, logistic, and order logistic regression, as appropriate. RESULTS: Despite a high number of ACEs, adolescent hours of sleep were consistent with published recommendations. Other measures of sleep indicated adolescents in the sample experience worse sleep on most other measures. ACE exposure was associated with difficulty falling asleep and staying asleep. More ACEs was also related with problematic sleep environments (i.e., place slept) and increased snoring. There was some evidence that ACEs were related to less sleep on weekends and increased social jet lag (different patterns of sleep between weekdays and weekends). CONCLUSIONS: Our findings suggest that ACEs could be important diagnostic data for clinicians in primary care and behavioral sleep medicine practice.

Marital Quality and Loneliness Among Aging Vietnam-Era Combat Veterans: The Moderating Role of PTSD Symptom Severity.

OBJECTIVES: We examined links between marital quality and loneliness among aging veterans and explored whether veterans' PTSD symptom severity moderated these associations. METHODS: Data came from 269 Vietnam-Era combat veterans who had a spouse/partner (M age = 60.50). Utilizing two waves of data spanning six years, we estimated multiple regression models that included positive and negative marital quality, PTSD symptom severity, and loneliness in 2010 as predictors of loneliness in 2016. RESULTS: Facets of positive (but not negative) marital quality were associated with veterans' loneliness. Companionship - spousal affection and understanding - was associated with lower subsequent loneliness among veterans with low/moderate - but not high - PTSD symptom severity. Conversely, sociability - the degree to which one's marriage promotes socializing with others - was associated with lower subsequent loneliness regardless of PTSD symptom severity. CONCLUSIONS: Companionship and sociability were each associated with veterans' subsequent loneliness. Whereas benefits of companionship were attenuated at higher levels of PTSD symptom severity, benefits of sociability were not. CLINICAL IMPLICATIONS: For veterans with higher PTSD symptoms, recommending mental health treatment to decrease symptom severity may help them to reap the benefits of close/intimate relationships. However, bolstering veterans' social participation more broadly may provide an additional means of reducing their loneliness.

Cardiovascular health, infection burden, and incident dementia in the UK Biobank.

INTRODUCTION: Among older adults, total and hospitalized infection may be associated with incidence of all-cause and Alzheimer's disease (AD) dementias, with variation by cardiovascular health (CVH). METHODS: We used Cox proportional hazards (PH) models to examine the relationships between International Classification of Diseases-10th revision (ICD-10)-specific viral and bacterial infectious agents and incident all-cause and AD dementia among 355,046 UK Biobank participants ≥50 years at baseline. Life's Essential 8 (LE8) index reflected CVH. RESULTS: In both sexes, total infection burden (yes vs. no) was associated with all-cause dementia, with significant interactions by LE8 tertiles, whereby this relationship was significant only in the lowest LE8 tertile. Hospital-treated infection burden (yes vs no) was significantly related to all-cause and AD dementia, with no significant interaction with LE8 tertile. Age group patterns were detected. DISCUSSION: AD and all-cause dementia were related to hospital-treated infections, while CVH modified the relationship of total infection burden with all-cause dementia. Highlights Secondary analysis on >355,000 UK Biobank participants ≥50 years at baseline. Alzheimer's disease and all-cause dementia are both related to hospital-treated infection. Cardiovascular health modifies association of infection burden with all-cause dementia.

Cardiovascular health, infection burden and their interactive association with brain volumetric and white matter integrity outcomes in the UK Biobank.

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.

Cognitive function in UK adults seropositive for Helicobacter pylori.

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.

Association between toxocariasis seropositivity and serointensity and cognitive function in older U.S. adults.

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.

Cytomegalovirus is not associated with cognitive function in UK adults aged 40 to 70 years.

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.

The association between air pollutants and hippocampal volume from magnetic resonance imaging: A systematic review and meta-analysis.

Growing epidemiological evidence suggests that air pollution may increase the risk of cognitive decline and neurodegenerative disease. A hallmark of neurodegeneration and an important diagnostic biomarker is volume reduction of a key brain structure, the hippocampus. We aimed to investigate the possibility that outdoor air nitrogen dioxide (NO2) and particulate matter with diameter ≤2.5 µm (PM2.5) and ≤10 µm (PM10) adversely affect hippocampal volume, through a meta-analysis. We considered studies that assessed the relation between outdoor air pollution and hippocampal volume by structural magnetic resonance imaging in adults and children, searching in Pubmed and Scopus databases from inception through July 13, 2021. For inclusion, studies had to report the correlation coefficient along with its standard error or 95% confidence interval (CI) between air pollutant exposure and hippocampal volume, to use standard space for neuroimages, and to consider at least age, sex and intracranial volume as covariates or effect modifiers. We meta-analyzed the data with a random-effects model, considering separately adult and child populations. We retrieved four eligible studies in adults and two in children. In adults, the pooled summary ß regression coefficients of the association of PM2.5, PM10 and NO2 with hippocampal volume showed respectively a stronger association (summary ß -7.59, 95% CI -14.08 to -1.11), a weaker association (summary ß -2.02, 95% CI -4.50 to 0.47), and no association (summary ß -0.44, 95% CI -1.27 to 0.40). The two studies available for children, both carried out in preadolescents, did not show an association between PM2.5 and hippocampal volume. The inverse association between PM2.5 and hippocampal volume in adults appeared to be stronger at higher mean PM2.5 levels. Our results suggest that outdoor PM2.5 and less strongly PM10 could adversely affect hippocampal volume in adults, a phenomenon that may explain why air pollution has been related to memory loss, cognitive decline, and dementia.

Association between Cognitive Function and Depression with Human T-Cell Lymphotropic Virus 1 Seropositivity and Serointensity in UK Adults.

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.

Examining the Relationship between Toxoplasma gondii and Seropositivity and Serointensity and Depression in Adults from the United Kingdom and the United States: A Cross-Sectional Study.

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.

Association between Toxoplasma gondii seropositivity and serointensity and brain volume in adults: A cross-sectional study.

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.

Natural mentoring relationships among survivors of caregiver childhood abuse: findings from the Add Health Study.

Social support promotes resilience to adverse childhood events, but little is known about the role of natural mentors-caring, nonparental adults-in the lives of childhood abuse survivors. The current study draws from a large, longitudinal, nationally representative sample (Add Health) to examine the prevalence and characteristics of natural mentoring relationships for adolescents with a history of caregiver childhood abuse, and the extent to which these relationships are associated with psychological and health outcomes in adulthood. Among the sample (n = 12,270), 28.82% and 4.86% reported caregiver childhood physical and sexual abuse, respectively. Youth who reported caregiver childhood physical abuse were more likely than those who did not endorse abuse to report having a natural mentor, but their mentoring relationships were characterized by lower interpersonal closeness, shorter duration, and less frequent contact. Exposure to caregiver childhood abuse was associated with adverse outcomes during adulthood, including antisocial behavior, physical health limitations, and suicidality; the presence of a natural mentor did not buffer the negative impact of trauma on adult outcomes. However, longer mentoring relationships during adolescence buffered the strength of the association between both caregiver physical and sexual abuse during childhood and suicidality during early adulthood.

Insomnia Is Associated With Frequency of Suicidal Ideation Independent of Depression: A Replication and Extension of Findings From the National Health and Nutrition Examination Survey.

OBJECTIVE: Insomnia is associated with suicidality, although the mechanisms of this association are unclear. This study sought to replicate previous findings showing that insomnia symptoms but not sleep duration are associated with frequency of suicidal ideation in adults. We further investigated whether depression or sleep duration moderates the association between insomnia symptoms and frequency of suicidal ideation. MATERIALS AND METHODS: We used the 2005-2006 cycle of the National Health and Nutrition Examination Survey to replicate previously reported findings from the 2007-2008 cycle. We used ordered logistic regression to determine whether insomnia symptoms were associated with frequency of suicidal ideation independently of depression and other potential confounds. To extend these findings, we tested whether depression or sleep duration moderated the association between insomnia symptoms and frequency of suicidal ideation. We further replicated these findings in parallel analyses using the combined data from the 2005-2006 and 2007-2008 cycles. RESULTS: This study replicated previous results showing that insomnia symptoms are associated with frequency of suicidal ideation in the NHANES 2005-2006 cycle (OR = 1.09, p < 0.05), even after adjusting for potentially confounding variables, including depression. Neither depression nor sleep duration moderated this association. Difficulty with sleep maintenance insomnia symptoms were most robustly associated with frequency of suicidal ideation (OR ≥ 1.97, p < 0.05). Sleep duration was not robustly associated with suicidal ideation. CONCLUSIONS: In this study, we found that insomnia symptoms were uniquely associated with frequency of suicidal ideation. This association cannot be explained by the shared association with depression or sleep duration.

Toxoplasma gondii seropositivity and serointensity and cognitive function in adults.

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.

Association between exposure to air pollution and thalamus volume in adults: A cross-sectional study.

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.

Association between Exposure to Air Pollution and Total Gray Matter and Total White Matter Volumes in Adults: A Cross-Sectional Study.

Total brain gray-matter and white-matter volumes can be indicators of overall brain health. Among the factors associated with gray-matter and white-matter volumes is exposure to air pollution. Using data from the UK Biobank, we sought to determine associations between several components of air pollution-PM2.5, PM2.5-10, PM10, nitrogen dioxide, and nitrogen oxides-and total gray-matter and total white-matter volumes in multivariable regression models in a large sample of adults. We found significant inverse associations between PM2.5 concentration and total white-matter volume and between PM2.5, PM2.5-10, PM10, nitrogen dioxide, and nitrogen oxide concentrations and total gray-matter volume in models adjusted for age, sex, body-mass index, self-assessment of overall health, frequency of alcohol use, smoking status, educational attainment, and income. These findings of pollutant-associated decreases in total gray-matter and total white-matter volumes are in the context of mean PM2.5 concentrations near the upper limit of the World Health Organization's recommendations. Similarly, mean PM10 concentrations were below the recommended upper limit, and nitrogen dioxide concentration was slightly above. Still, there are many areas in the world with much higher concentrations of these pollutants, which could be associated with larger effects. If replicated, these findings suggest that air pollution could be a risk factor for neurodegeneration.

Association between exposure to air pollution and prefrontal cortical volume in adults: A cross-sectional study from the UK biobank.

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.

Cardiovascular factors moderate the association of infection burden with cognitive function in young to middle-aged U.S. adults.

BACKGROUND: Infectious diseases might affect cognitive aging and dementia risk, possibly via neuroinflammation. Similarly, risk factors for cardiovascular and cerebrovascular diseases are associated with cognitive function and dementia. We hypothesized that cardiovascular risk factors moderate the association of exposure to infectious diseases with cognitive function. METHODS: We studied 5662 participants aged 20 to 59 years from the third National Health and Nutrition Examination Survey (1988-1994) in the United States. We used linear regression to investigate whether the Framingham general cardiovascular risk index moderated the association of infection burden based on exposure to eight different infectious diseases with cognitive functioning as measured by the Symbol Digit Substitution, Serial Digit Learning, and Reaction Time tests. RESULTS: The multiplicative interaction between the infection-burden index and the cardiovascular-risk index was associated with performance on the Symbol Digit Substitution (B = .019 [95% CI: .008, .031], p < .001) but not on the Serial Digit Learning (B = .034 [95% CI: -.025, .094]) or for Reaction Time (B = -.030 [95% CI: -.848, .787]). Participants with a lower cardiovascular risk appeared to be more resilient against the potential adverse effects of higher infection burden on the Symbol Digit Substitution task. CONCLUSIONS: Participants at zero risk for a cardiovascular event in the next 10 years had no differences in processing speed with increasing exposure to infectious disease, whereas participants with higher risk for a cardiovascular event had worse processing speed with increased exposure to infectious disease.

Association between exposure to air pollution and hippocampal volume in adults in the UK Biobank.

BACKGROUND: The hippocampus is important for memory processing. Several neuropsychiatric diseases including Alzheimer's disease are associated with reduced hippocampal volume, and further the hippocampus appears vulnerable to environmental insult. Air pollution has been associated with cardiovascular disease, abnormal brain structure, and cognitive deficits. OBJECTIVE: Because of hippocampal vulnerability to environmental insults and based on the association between exposure to air pollution and cognitive function and brain structure, we evaluated the association between exposure to toxins in air pollution and left and right hippocampal volume using brain-imaging and air-pollution data from the UK Biobank, a large community-based dataset. METHODS: We used regression modelling to evaluate the association between exposure to nitrogen dioxide, nitrogen oxides, PM2.5, PM2.5-10, and PM10. and left and right hippocampal volume controlling for age, sex, body-mass index, overall health, alcohol use, smoking, educational attainment, socioeconomic status, inverse distance from the nearest major road, and a measure of total brain volume. RESULTS: In these models, PM2.5 concentration was associated with smaller left hippocampal volume. None of the other measures of air pollution was associated with either left or right hippocampal volume, although interaction models provided some evidence that sex might moderate the relationship between air pollution and hippocampal volume. In adjusted models, age, sex, educational attainment, income, overall health, current smoking, alcohol intake, and body-mass index were associated with hippocampal volume. CONCLUSIONS: PM2.5 at levels found in the United Kingdom was associated with smaller left hippocampal volume. Additional associations between several covariates and hippocampal volumes indicate that hippocampal volume might be associated with several potentially modifiable variables.

Toxoplasma gondii seropositivity and substance use in US adults.

The intracellular parasite Toxoplasma gondii (Nicolle et Manceaux, 1908) infects humans resulting in acute toxoplasmosis, an infection that in immunocompetent people is typically mild but results in persistent latent toxoplasmosis. In that T. gondii appears to affect dopamine synthesis and because addicting drugs affect midbrain dopamine transmission, latent toxoplasmosis could influence substance use. Using both the third and continuous National Health and Nutrition Examination Surveys from the US Centers for Disease Control and Prevention, we used logistic regression to test for associations between T. gondii seropositivity and subject self-report of having ever used tobacco, alcohol, marijuana, cocaine, heroin, or methamphetamine. In the third NHANES dataset, which included data for tobacco, alcohol, marijuana and cocaine, T. gondii seropositivity was associated with a reduced likelihood of self-reported marijuana (OR = 0.71 [95% CI: 0.58; 0.87]; p = 0.001) and cocaine use (OR = 0.72 [95% CI: 0.56; 0.91]; p = 0.006). In the continuous National Health and Nutrition Examination Surveys dataset, which included data for all six substances, T. gondii seropositivity was associated with a reduced likelihood of self-reported tobacco (OR = 0.87 [95% CI: 0.76; 1.00]; p = 0.044), marijuana (OR = 0.60 [95% CI: 0.50; 0.72]; p < 0.001), heroin (OR = 0.60 [95% CI: 0.42; 0.85]; p = 0.005) and methamphetamine use (OR = 0.54 [95% CI: 0.38; 0.77]; p = 0.001). We observed interactions between sex and T. gondii seropositivity in the prediction of self-reported use of tobacco and alcohol. Further, T. gondii seropositivity appeared to remove the protective effect of education and economic status against self-reported cigarette smoking. These findings suggest that T. gondii seropositivity may be inversely associated with some but not all types of substance use in US adults.