Intrinsic motoneuron properties in typical human development.

Motoneuron properties and their firing patterns undergo significant changes throughout development and in response to neuromodulators such as serotonin. Here, we examined the age-related development of self-sustained firing and general excitability of tibialis anterior motoneurons in a young development (7-17 years), young adult (18-28 years) and adult (32-53 years) group, as well as in a separate group of participants taking selective serotonin reuptake inhibitors (SSRIs, aged 11-28 years). Self-sustained firing, as measured by ΔF, was larger in the young development (∼5.8 Hz, n = 20) compared to the young adult (∼4.9 Hz, n = 13) and adult (∼4.8 Hz, n = 8) groups, consistent with a developmental decrease in self-sustained firing mediated by persistent inward currents (PIC). ΔF was also larger in participants taking SSRIs (∼6.5 Hz, n = 9) compared to their age-matched controls (∼5.3 Hz, n = 26), consistent with increased levels of spinal serotonin facilitating the motoneuron PIC. Participants in the young development and SSRI groups also had higher firing rates and a steeper acceleration in initial firing rates (secondary ranges), consistent with the PIC producing a steeper acceleration in membrane depolarization at the onset of motoneuron firing. In summary, both the young development and SSRI groups exhibited increased intrinsic motoneuron excitability compared to the adults, which, in the young development group, was also associated with a larger unsteadiness in the dorsiflexion torque profiles. We propose several intrinsic and extrinsic factors that affect both motoneuron PICs and cell discharge which vary during development, with a time course similar to the changes in motoneuron firing behaviour observed in the present study. KEY POINTS: Neurons in the spinal cord that activate muscles in the limbs (motoneurons) undergo increases in excitability shortly after birth to help animals stand and walk. We examined whether the excitability of human ankle flexor motoneurons also continues to change from child to adulthood by recording the activity of the muscle fibres they innervate. Motoneurons in children and adolescents aged 7-17 years (young development group) had higher signatures of excitability that included faster firing rates and more self-sustained activity compared to adults aged ≥18 years. Participants aged 11-28 years of age taking serotonin reuptake inhibitors had the highest measures of motoneuron excitability compared to their age-matched controls. The young development group also had more unstable contractions, which might partly be related to the high excitability of the motoneurons.

Association of midlife air pollution exposures and residential road proximity with incident dementia: The Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: Increasing evidence links higher air pollution exposures to increased risk of cognitive impairment. While midlife risk factors are often most strongly linked to dementia risk, few studies have considered associations between midlife roadway proximity or ambient air pollution exposure and incident dementia decades later, in late life. OBJECTIVES: Our objective was to determine if midlife exposures to ambient air pollution or roadway proximity are associated with increased risk of dementia in the Atherosclerosis Risk in Communities (ARIC) study over up to 29 years of follow-up. METHODS: Our eligible sample included Black and White ARIC participants without dementia at Visit 2 (1990-1992). Participants were followed through Visit 7 (2018-2019), with dementia status and onset date defined based on formal dementia ascertainment at study visits, informant interviews, and surveillance efforts. We used adjusted Weibull survival models to assess the associations of midlife ambient air pollution and road proximity with incident dementia. RESULTS: The median age at baseline (1990-1992, Visit 2) of the 12,700 eligible ARIC participants was 57.0 years; 56.0% were female, 24.2% were Black, and 78.9% had at least a high school education. Over up to 29 years of follow-up, 2511 (19.8%) persons developed dementia. No associations were found between ambient air pollutants and proximity to major roadways with risk of incident dementia. In exploratory analyses, living closer to roadways in midlife increased dementia risk in individuals younger at baseline and those without midlife hypertension, and there was evidence of increased risk of dementia with increased midlife exposure to NOx, several PM2.5 components, and trace metals among those with diabetes in midlife. CONCLUSIONS: Midlife exposure to ambient air pollution and midlife roadway proximity was not associated with dementia risk over decades of follow-up. Further investigation to explore potential for greater susceptibility among specific subgroups identified here is needed.

A comparison of PM2.5 exposure estimates from different estimation methods and their associations with cognitive testing and brain MRI outcomes.

BACKGROUND: Reported associations between particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5) and cognitive outcomes remain mixed. Differences in exposure estimation method may contribute to this heterogeneity. OBJECTIVES: To assess agreement between PM2.5 exposure concentrations across 11 exposure estimation methods and to compare resulting associations between PM2.5 and cognitive or MRI outcomes. METHODS: We used Visit 5 (2011-2013) cognitive testing and brain MRI data from the Atherosclerosis Risk in Communities (ARIC) Study. We derived address-linked average 2000-2007 PM2.5 exposure concentrations in areas immediately surrounding the four ARIC recruitment sites (Forsyth County, NC; Jackson, MS; suburbs of Minneapolis, MN; Washington County, MD) using 11 estimation methods. We assessed agreement between method-specific PM2.5 concentrations using descriptive statistics and plots, overall and by site. We used adjusted linear regression to estimate associations of method-specific PM2.5 exposure estimates with cognitive scores (n = 4678) and MRI outcomes (n = 1518) stratified by study site and combined site-specific estimates using meta-analyses to derive overall estimates. We explored the potential impact of unmeasured confounding by spatially patterned factors. RESULTS: Exposure estimates from most methods had high agreement across sites, but low agreement within sites. Within-site exposure variation was limited for some methods. Consistently null findings for the PM2.5-cognitive outcome associations regardless of method precluded empirical conclusions about the potential impact of method on study findings in contexts where positive associations are observed. Not accounting for study site led to consistent, adverse associations, regardless of exposure estimation method, suggesting the potential for substantial bias due to residual confounding by spatially patterned factors. DISCUSSION: PM2.5 estimation methods agreed across sites but not within sites. Choice of estimation method may impact findings when participants are concentrated in small geographic areas. Understanding unmeasured confounding by factors that are spatially patterned may be particularly important in studies of air pollution and cognitive or brain health.

Toxic Tire Wear Compounds (6PPD-Q and 4-ADPA) Detected in Airborne Particulate Matter Along a Highway in Mississippi, USA.

Tire wear particles (TWPs) are a major category of microplastic pollution produced by friction between tires and road surfaces. This non-exhaust particulate matter (PM) containing leachable toxic compounds is transported through the air and with stormwater runoff, leading to environmental pollution and human health concerns. In the present study, we collected airborne PM at varying distances (5, 15 and 30 m) along US Highway 278 in Oxford, Mississippi, USA, for ten consecutive days using Sigma-2 passive samplers. Particles (~ 1-80 µm) were passively collected directly into small (60 mL) wide-mouth separatory funnels placed inside the samplers. Particles were subsequently subjected to solvent extraction, and extracts were analyzed for TWP compounds by high resolution orbitrap mass spectrometry. This pilot study was focused solely on qualitative analyses to determine whether TWP compounds were present in this fraction of airborne PM. The abundance of airborne TWPs increased with proximity to the road with deposition rates (TWPs cm-2 day-1) of 23, 47, and 63 at 30 m, 15 m, and 5 m from the highway, respectively. Two common TWP compounds (6PPD-Q and 4-ADPA) were detected in all samples, except the field blank, at levels above their limits of detection, estimated at 2.90 and 1.14 ng L-1, respectively. Overall, this work suggests airborne TWPs may be a potential inhalation hazard, particularly for individuals and wildlife who spend extended periods outdoors along busy roadways. Research on the bioavailability of TWP compounds from inhaled TWPs is needed to address exposure risk.

Fostering Resilience in Nursing Through R.E.S.T.

ABSTRACT: With about one-third of nurses having expressed an intention to leave the profession or change jobs in 2022, the effects of nursing job stress are evident. For nurses to continue to provide care in high stress, they must practice self-compassion and build resilience. The importance of resilience education and self-compassion for nurses and in nursing education is discussed from a Christian perspective, along with self-care strategies using the R.E.S.T. (Relationship, Exercise, Self-Compassion, Transformative Thinking) framework. Strategies for building resilience for both individuals and organizations are offered.

The Associations of Dietary Copper With Cognitive Outcomes.

Dietary copper intake may be associated with cognitive decline and dementia. We used data from 10,269 participants of the Atherosclerosis Risks in Communities Study to study the associations of dietary copper intake with 20-year cognitive decline and incident dementia. Dietary copper intake from food and supplements was quantified using food frequency questionnaires. Cognition was assessed using 3 cognitive tests at study visits; dementia was ascertained at study visits and via surveillance. Multiple imputation by chained equations was applied to account for the missing information of cognitive function during follow-up. Survival analysis with parametric models and mixed-effect models were used to estimate the associations for incident dementia and cognitive decline, respectively. During 20 years of follow-up (1996-1998 to 2016-2017), 1,862 incident cases of dementia occurred. Higher intake of dietary copper from food was associated with higher risk of incident dementia among those with high intake of saturated fat (hazard ratio = 1.49, 95% confidence interval: 1.04, 1.95). Higher intake of dietary copper from food was associated with greater decline in language overall (beta = -0.12, 95% confidence interval: -0.23, -0.02). Therefore, a diet high in copper, particularly when combined with a diet high in saturated fat, may increase the risk of cognitive impairment.

Prevalence of specialised palliative care consultation for eligible children within a paediatric cardiac ICU.

OBJECTIVE: Retrospectively apply criteria from Center to Advance Palliative Care to a cohort of children treated in a cardiac ICU and compare children who received a palliative care consultation to those who were eligible for but did not receive one. METHODS: Medical records of children admitted to a cardiac ICU between January 2014 and June 2017 were reviewed. Selected criteria include cardiac ICU length of stay >14 days and/or ≥ 3 hospitalisations within a 6-month period. MEASUREMENTS AND RESULTS: A consultation occurred in 17% (n = 48) of 288 eligible children. Children who received a consult had longer cardiac ICU (27 days versus 17 days; p < 0.001) and hospital (91 days versus 35 days; p < 0.001) lengths of stay, more complex chronic conditions at the end of first hospitalisation (3 versus1; p < 0.001) and the end of the study (4 vs.2; p < 0.001), and higher mortality (42% versus 7%; p < 0.001) when compared with the non-consulted group. Of the 142 pre-natally diagnosed children, only one received a pre-natal consult and 23 received it post-natally. Children who received a consultation (n = 48) were almost 2 months of age at the time of the consult. CONCLUSIONS: Less than a quarter of eligible children received a consultation. The consultation usually occurred in the context of medical complexity, high risk of mortality, and at an older age, suggesting potential opportunities for more and earlier paediatric palliative care involvement in the cardiac ICU. Screening criteria to identify patients for a consultation may increase the use of palliative care services in the cardiac ICU.

Generalizability of findings from a clinical sample to a community-based sample: A comparison of ADNI and ARIC.

INTRODUCTION: Clinic-based study samples, including the Alzheimer's Disease Neuroimaging Initiative (ADNI), offer rich data, but findings may not generalize to community-based settings. We compared associations in ADNI to those in the Atherosclerosis Risk in Communities (ARIC) study to assess generalizability across the two settings. METHODS: We estimated cohort-specific associations among risk factors, cognitive test scores, and neuroimaging outcomes to identify and quantify the extent of significant and substantively meaningful differences in associations between cohorts. We explored whether using more homogenous samples improved comparability in effect estimates. RESULTS: The proportion of associations that differed significantly between cohorts ranged from 27% to 34% across sample subsets. Many differences were substantively meaningful (e.g., odds ratios [OR] for apolipoprotein E ε4 on amyloid positivity in ARIC: OR = 2.8, in ADNI: OR = 8.6). DISCUSSION: A higher proportion of associations differed significantly and substantively than would be expected by chance. Findings in clinical samples should be confirmed in more representative samples.

Palliative Care in Children With Heart Disease Treated in an ICU.

OBJECTIVES: Describe pediatric palliative care consult in children with heart disease; retrospectively apply Center to Advance Palliative Care criteria for pediatric palliative care consults; determine the impact of pediatric palliative care on end of life. DESIGN: A retrospective single-center study. SETTING: A 16-bed cardiac ICU in a university-affiliated tertiary care children's hospital. PATIENTS: Children (0-21 yr old) with heart disease admitted to the cardiac ICU from January 2014 to June 2017. MEASUREMENTS AND MAIN RESULTS: Over 1,000 patients (n = 1, 389) were admitted to the cardiac ICU with 112 (8%) receiving a pediatric palliative care consultation. Patients who received a consult were different from those who did not. Patients who received pediatric palliative care were younger at first hospital admission (median 63 vs 239 d; p = 0.003), had a higher median number of complex chronic conditions at the end of first hospitalization (3 vs 1; p < 0.001), longer cumulative length of stay in the cardiac ICU (11 vs 2 d; p < 0.001) and hospital (60 vs 7 d; p < 0.001), and higher mortality rates (38% vs 3%; p < 0.001). When comparing location and modes of death, patients who received pediatric palliative care were more likely to die at home (24% vs 2%; p = 0.02) and had more comfort care at the end of life (36% vs 2%; p = 0.002) compared to those who did not. The Center to Advance Palliative Care guidelines identified 158 patients who were eligible for pediatric palliative care consultation; however, only 30 patients (19%) in our sample received a consult. CONCLUSIONS: Pediatric palliative care consult rarely occurred in the cardiac ICU. Patients who received a consult were medically complex and experienced high mortality. Comfort care at the end of life and death at home was more common when pediatric palliative care was consulted. Missed referrals were apparent when Center to Advance Palliative Care criteria were retrospectively applied.

Acute Presentation and Management of the Encephalopathic Child With an Undiagnosed Inborn Error of Metabolism.

BACKGROUND: Inborn errors of metabolism (IEM) commonly present in infancy and, less commonly, later in life. CASE REPORT: This case describes an IEM, specifically, ornithine transcarbamylase deficiency, in a previously healthy 7-year-old boy who presented to an emergency department with vomiting for approximately 24 h prior to admission. The child became progressively encephalopathic while in the emergency department, but an ammonia level was not obtained until several hours after admission. Irreversible brain damage with cerebral edema was already present at time of diagnosis, leading to death. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case emphasizes that acute hyperammonemia can rapidly cause irreversible neurological damage and, in the case of a newly encephalopathic pediatric patient, ammonia levels should be evaluated early to facilitate proper diagnostic tests and treatment.

The hazards and benefits of social media use in adolescents.

Studies have found that social media can act as a catalyst to negative attitudes and behaviors in adolescents. This article reviews the current evidence and explores if there is a connection between social media and mental health issues.

Pediatric Organ Donation Potential at a Children's Hospital.

OBJECTIVES: To estimate the organ donation potential of patients dying at a children's hospital. DESIGN: Retrospective cohort study. SETTING: A free-standing, 271-bed, tertiary Children's Hospital with a pediatric trauma center. PATIENTS: Patients dying in any ICU during 2011-2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 224 deaths, 23 (10%) met neurologic criteria for death: 18 donated organs (conversion rate 78%), 47 (19%) died without prior limitation of life-sustaining therapies, and the remaining 69% had withdrawal of life-sustaining therapies. Among those dying after withdrawal of life-sustaining therapies (n = 154), the organ procurement organization was not notified prior to death in 24%, and older patients were more likely to be referred compared to those less than 1 year old. Infection, cancer, and organ dysfunction were the most frequent conditions that disqualified dying patients from suitability for donation. Just over half of children more than 1 year old were suitable for donation after withdrawal of life-sustaining therapies compared to a fifth of infants (19%). Of 45 suitable for donation, 37 (82%) died within 1 hour. None of 7 infants younger than 1 month old died within 20 minutes, compared with 46% of infants between 1 month and 1 year (n = 6) and 72% of older children. Thirty-three families (73%) did not permit donation after circulatory criteria for death whereas 12 (27%) gave permission for donation, and all 12 were actual donors (conversion rate 12/37 [32%]). CONCLUSIONS: The number of pediatric potential candidates for donation after circulatory determination of death was significantly larger than potential candidates for donation after neurologic determination of death at our hospital, but the actual donation rate was significantly lower. Increasing acceptance of donation after circulatory determination of death could increase organ donation. Among all children having withdrawal of life-sustaining therapies, donation after circulatory determination of death potential is less for infants.

The changing face of BECT: a citation analysis covering 1966-2009.

A citation analysis was completed on articles published in Bulletin of Environmental Contamination and Toxicology over the period of 1966-2009. Articles were grouped into 5 year intervals and the top 50 most-cited papers in each year interval were categorized according to research theme. Over the journal's history, articles in the toxicity research theme dominated top-cited articles published by the journal followed by articles in the environmental concentration theme and the mechanistic theme. The geographic area of submission of top-cited articles has shown large changes with time, initially being dominated by papers from North American and now dominated by papers from Asia. An examination of the citation history for the highest cited paper in each year interval indicated that the average time to achieve 90 % of total citations is 25 years.

Antithrombin activity and central venous catheter-associated thrombosis in critically ill children at high risk of bleeding.

BACKGROUND: Normalization of antithrombin activity may prevent catheter-associated thrombosis in critically ill children at high risk of bleeding. OBJECTIVES: To characterize the temporal pattern of antithrombin activity, assess its association with catheter-associated thrombosis and clinically relevant bleeding, and evaluate its relationship with thrombin generation in these children. METHODS: In this prospective cohort study, critically ill children <18 years old at high risk of bleeding with central venous catheter were eligible. Antithrombin activity and thrombin generation were measured from platelet-poor plasma and after in vitro antithrombin supplementation. Systematic surveillance ultrasound was performed to diagnose thrombosis. Children were followed for bleeding. RESULTS: We enrolled 8 infants (median age: 0.2 years, IQR: 0.2, 0.3 years) and 72 older children (median age: 14.3 years, IQR: 9.1, 16.1 years). Mean antithrombin on the day of catheter insertion was 64 IU/dL (SD: 32 IU/dL) in infants and 83 IU/dL (SD: 35 IU/dL) in older children. Antithrombin normalized by the day of catheter removal. Thrombosis developed in 27 children, while 31 children bled. Thrombosis (regression coefficient: 0.008, 95% CI: -0.01, 0.03) and bleeding (regression coefficient: -0.0007, 95% CI: -0.02, 0.02) were not associated with antithrombin. Antithrombin was not correlated with in vivo change in endogenous thrombin potential (correlation coefficient: -0.07, 95% CI: -0.21, 0.08). In vitro supplementation reduced endogenous thrombin potential (correlation coefficient: -0.78; 95% CI: -0.95, -0.23). CONCLUSION: These findings may not support normalization of antithrombin activity to prevent catheter-associated thrombosis in critically ill children at high risk of bleeding.

Association of Gaseous Ambient Air Pollution and Dementia-Related Neuroimaging Markers in the ARIC Cohort, Comparing Exposure Estimation Methods and Confounding by Study Site.

BACKGROUND: Evidence linking gaseous air pollution to late-life brain health is mixed. OBJECTIVE: We explored associations between exposure to gaseous pollutants and brain magnetic resonance imaging (MRI) markers among Atherosclerosis Risk in Communities (ARIC) Study participants, with attention to the influence of exposure estimation method and confounding by site. METHODS: We considered data from 1,665 eligible ARIC participants recruited from four US sites in the period 1987-1989 with valid brain MRI data from Visit 5 (2011-2013). We estimated 10-y (2001-2010) mean carbon monoxide (CO), nitrogen dioxide (NO2), nitrogen oxides (NOx), and 8- and 24-h ozone (O3) concentrations at participant addresses, using multiple exposure estimation methods. We estimated site-specific associations between pollutant exposures and brain MRI outcomes (total and regional volumes; presence of microhemorrhages, infarcts, lacunes, and severe white matter hyperintensities), using adjusted linear and logistic regression models. We compared meta-analytically combined site-specific associations to analyses that did not account for site. RESULTS: Within-site exposure distributions varied across exposure estimation methods. Meta-analytic associations were generally not statistically significant regardless of exposure, outcome, or exposure estimation method; point estimates often suggested associations between higher NO2 and NOx and smaller temporal lobe, deep gray, hippocampal, frontal lobe, and Alzheimer disease signature region of interest volumes and between higher CO and smaller temporal and frontal lobe volumes. Analyses that did not account for study site more often yielded significant associations and sometimes different direction of associations. DISCUSSION: Patterns of local variation in estimated air pollution concentrations differ by estimation method. Although we did not find strong evidence supporting impact of gaseous pollutants on brain changes detectable by MRI, point estimates suggested associations between higher exposure to CO, NOx, and NO2 and smaller regional brain volumes. Analyses of air pollution and dementia-related outcomes that do not adjust for location likely underestimate uncertainty and may be susceptible to confounding bias. https://doi.org/10.1289/EHP13906.

Comparison of PM2.5 Air Pollution Exposures and Health Effects Associations Using 11 Different Modeling Approaches in the Women's Health Initiative Memory Study (WHIMS).

BACKGROUND: Many approaches to quantifying air pollution exposures have been developed. However, the impact of choice of approach on air pollution estimates and health-effects associations remains unclear. OBJECTIVES: Our objective is to compare particulate matter with aerodynamic diameter ≤2.5µm (PM2.5) concentrations and resulting health effects associations using multiple estimation approaches previously used in epidemiologic analyses. METHODS: We assigned annual PM2.5 exposure estimates from 1999 to 2004 derived from 11 different approaches to Women's Health Initiative Memory Study (WHIMS) participant addresses within the contiguous US. Approaches included geostatistical interpolation approaches, land-use regression or spatiotemporal models, satellite-derived approaches, air dispersion and chemical transport models, and hybrid models. We used descriptive statistics and plots to assess relative and absolute agreement among exposure estimates and examined the impact of approach on associations between PM2.5 and death due to natural causes, cardiovascular disease (CVD) mortality, and incident CVD events, adjusting for individual-level covariates and climate-based region. RESULTS: With a few exceptions, relative agreement of approach-specific PM2.5 exposure estimates was high for PM2.5 concentrations across the contiguous US. Agreement among approach-specific exposure estimates was stronger near PM2.5 monitors, in certain regions of the country, and in 2004 vs. 1999. Collectively, our results suggest but do not quantify lower agreement at local spatial scales for PM2.5. There was no evidence of large differences in health effects associations with PM2.5 among estimation approaches in analyses adjusted for climate region. CONCLUSIONS: Different estimation approaches produced similar spatial patterns of PM2.5 concentrations across the contiguous US and in areas with dense monitoring data, and PM2.5-health effects associations were similar among estimation approaches. PM2.5 estimates and PM2.5-health effects associations may differ more in samples drawn from smaller areas or areas without substantial monitoring data, or in analyses with finer adjustment for participant location. Our results can inform decisions about PM2.5 estimation approach in epidemiologic studies, as investigators balance concerns about bias, efficiency, and resource allocation. Future work is needed to understand whether these conclusions also apply in the context of other air pollutants of interest. https://doi.org/10.1289/EHP12995.

Timing of Pediatric Palliative Care Consults in Hospitalized Patients with Heart Disease.

Pediatric palliative care (PPC) provides an extra layer of support for families caring for a child with complex heart disease as these patients often experience lifelong morbidities with frequent hospitalizations and risk of early mortality. PPC referral at the time of heart disease diagnosis provides early involvement in the disease trajectory, allowing PPC teams to longitudinally support patients and families with symptom management, complex medical decision-making, and advanced care planning. We analyzed 113 hospitalized pediatric patients with a primary diagnosis of heart disease and a PPC consult to identify timing of first PPC consultation in relation to diagnosis, complex chronic conditions (CCC), and death. The median age of heart disease diagnosis was 0 days with a median of two CCCs while PPC consultation did not occur until a median age of 77 days with a median of four CCCs. Median time between PPC consult and death was 33 days (interquartile range: 7-128). Death often occurred in the intensive care unit ( n = 36, 67%), and the most common mode was withdrawal of life-sustaining therapies ( n = 31, 57%). PPC referral often occurred in the context of medical complexity and prolonged hospitalization. Referral close to the time of heart disease diagnosis would allow patients and families to fully utilize PPC benefits that exist outside of end-of-life care and may influence the mode and location of death. PPC consultation should be considered at the time of heart disease diagnosis, especially in neonates and infants with CCCs.

The association of long-term exposure to criteria air pollutants, fine particulate matter components, and airborne trace metals with late-life brain amyloid burden in the Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: Studies suggest associations between long-term ambient air pollution exposure and outcomes related to Alzheimer's disease (AD). Whether a link exists between pollutants and brain amyloid accumulation, a biomarker of AD, is unclear. We assessed whether long-term air pollutant exposures are associated with late-life brain amyloid deposition in Atherosclerosis Risk in Communities (ARIC) study participants. METHODS: We used a chemical transport model with data fusion to estimate ambient concentrations of PM2.5 and its components, NO2, NOx, O3 (24-hour and 8-hour), CO, and airborne trace metals. We linked concentrations to geocoded participant addresses and calculated 10-year mean exposures (2002 to 2011). Brain amyloid deposition was measured using florbetapir amyloid positron emission tomography (PET) scans in 346 participants without dementia in 2012-2014, and we defined amyloid positivity as a global cortical standardized uptake value ratio ≥ the sample median of 1.2. We used logistic regression models to quantify the association between amyloid positivity and each air pollutant, adjusting for putative confounders. In sensitivity analyses, we considered whether use of alternate air pollution estimation approaches impacted findings for PM2.5, NO2, NOx, and 24-hour O3. RESULTS: At PET imaging, eligible participants (N = 318) had a mean age of 78 years, 56% were female, 43% were Black, and 27% had mild cognitive impairment. We did not find evidence of associations between long-term exposure to any pollutant and brain amyloid positivity in adjusted models. Findings were materially unchanged in sensitivity analyses using alternate air pollution estimation approaches for PM2.5, NO2, NOx, and 24-hour O3. CONCLUSIONS: Air pollution may impact cognition and dementia independent of amyloid accumulation, though whether air pollution influences AD pathogenesis later in the disease course or at higher exposure levels deserves further consideration.