The Role of Traffic-Related Air Pollution on Neurodegenerative Diseases in Older People: An Epidemiological Perspective

"We Used to Have Four Seasons, but Now There Is Only One": Perceptions Concerning the Changing Climate and Environment in a Diverse Sample of Israeli Older Persons

Solastalgia is the pain caused by the loss of solace and isolation from one's environment. Solastalgia is contrasted with nostalgia, which is defined as melancholy characterized by homesickness or the distance from one's home. The present study examines the two concepts of solastalgia and nostalgia in the context of climate change among diverse populations of older Israelis. In total, 50 older persons from four different population groups (e.g., veteran Israeli Jews, Israeli Arabs, immigrants from the former Soviet Union, and Ethiopian immigrants) were interviewed. All interviews were transcribed and analyzed thematically. Members of all four groups expressed emotional distress and grief associated with the changing climate, increased environmental pollution, and the disappearance of nature. Perceptions around the undesirability of these changes were quite unanimous, thus leading us to conclude that the outcomes associated with solastalgia and nostalgia are quite similar despite different etiological explanations.

Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the US

Importance

Emerging evidence indicates that exposure to fine particulate matter (PM2.5) air pollution may increase dementia risk in older adults. Although this evidence suggests opportunities for intervention, little is known about the relative importance of PM2.5 from different emission sources.

Objective

To examine associations of long-term exposure of total and source-specific PM2.5 with incident dementia in older adults.

Design, Setting, and Participants

The Environmental Predictors of Cognitive Health and Aging study used biennial survey data from January 1, 1998, to December 31, 2016, for participants in the Health and Retirement Study, which is a nationally representative, population-based cohort study in the US. The present cohort study included all participants older than 50 years who were without dementia at baseline and had available exposure, outcome, and demographic data between 1998 and 2016 (N = 27 857). Analyses were performed from January 31 to May 1, 2022.

Exposures

The 10-year mean total PM2.5 and PM2.5 from 9 emission sources at participant residences for each month during follow-up using spatiotemporal and chemical transport models.

Main Outcomes and Measures

The main outcome was incident dementia as classified by a validated algorithm incorporating respondent-based cognitive testing and proxy respondent reports. Adjusted hazard ratios (HRs) were estimated for incident dementia per IQR of residential PM2.5 concentrations using time-varying, weighted Cox proportional hazards regression models with adjustment for the individual- and area-level risk factors.

Results

Among 27 857 participants (mean [SD] age, 61 [10] years; 15 747 [56.5%] female), 4105 (15%) developed dementia during a mean (SD) follow-up of 10.2 [5.6] years. Higher concentrations of total PM2.5 were associated with greater rates of incident dementia (HR, 1.08 per IQR; 95% CI, 1.01-1.17). In single pollutant models, PM2.5 from all sources, except dust, were associated with increased rates of dementia, with the strongest associations for agriculture, traffic, coal combustion, and wildfires. After control for PM2.5 from all other sources and copollutants, only PM2.5 from agriculture (HR, 1.13; 95% CI, 1.01-1.27) and wildfires (HR, 1.05; 95% CI, 1.02-1.08) were robustly associated with greater rates of dementia.

Conclusion and Relevance

In this cohort study, higher residential PM2.5 levels, especially from agriculture and wildfires, were associated with higher rates of incident dementia, providing further evidence supporting PM2.5 reduction as a population-based approach to promote healthy cognitive aging. These findings also indicate that intervening on key emission sources might have value, although more research is needed to confirm these findings.

Traffic-related air pollution, adherence to healthy lifestyles, and risk of cognitive impairment: A nationwide population-based study

BACKGROUND

Traffic-related air pollution (TRAP) is a risk factor for cognitive function, whereas healthy lifestyles are associated with better cognition. We aimed to examine their joint effects on cognition among the Chinese elderly.

METHODS

The data from the Chinese Longitudinal Healthy Longevity Survey was used. Participants' cognitive performance was assessed by the Chinese version of the mini-mental state examination. Residential proximity to major roadways was obtained through self-report and categorized into five categories: > 300 m, 201-300 m, 101-200 m, 50-100 m, and < 50 m, serving as a surrogate for TRAP. Six lifestyle behaviors (smoking, drinking, exercise, body mass index, sleep duration, and dietary diversity) were taken into account to calculate healthy lifestyle scores. The scores ranged from zero to six and were then divided into three groups: healthy (5-6), intermediate (2-4), and unhealthy (0-1). Logistic regression models were applied to investigate the joint effects of TRAP and healthy lifestyle scores on cognition.

RESULTS

Compared to participants living < 50 m from major roadways and adopting an unhealthy lifestyle, those living > 300 m from major roadways and adopting a healthy lifestyle had a significantly decreased risk of cognitive impairment. Stratified analysis indicated that the associations between TRAP and cognitive impairment were more pronounced among participants adopting an unhealthy lifestyle compared to the participants adopting a healthy lifestyle.

CONCLUSIONS

TRAP may impair cognitive function, and its detrimental impacts may be lessened by healthy lifestyles.

The role of chronological age in climate change attitudes, feelings, and behavioral intentions: The case of null results

Past research has stressed the role of age and generation in climate change discourse, worries, and willingness to act. Therefore, the present paper aimed to examine the role of chronological age (as an arbitrary factor, which represents ageism) in lay people's climate change-related attitudes, feelings, and behavioral intentions. Two experiments in different countries, Australia and Israel, were conducted for this purpose. The first study examined the impact of the age of the speaker, who provides information about the climate crisis and the second examined the impact of the age of the group being blamed for the situation. Outcome variables included perceived responsibility and motivation for the current climate situation in study 1 and perceived climate change-related attitudes, feelings, and behavioral intentions in study 2. In study 1 (n = 250, Australia), the age of the speaker, a climate activist, varied randomly to test the hypothesis that a younger activist would be more influential and increase motivation and responsibility to act compared to an older activist. In study 2 (n = 179, Israel), the age (young vs. old) of the group identified as being responsible for the climate crisis varied randomly, to test the hypothesis that people would be more willing to identify older people as being responsible for the current climate situation, and this would impact climate change-related attitudes, feelings, and behavioral intentions. Both studies resulted in null effects. Additionally, there was no interaction between the age of the respondent and the age of the source of the message or the age group being blamed by the message. The present study has failed to show that strategies that emphasize intergenerational conflict and ageism impact people's attitudes, feelings, and behavioral intentions towards the current climate situation. This possibly can serve as an instigator for strategies that emphasize intergenerational solidarity, rather than conflict, as a guiding principle in future campaigns that advocate climate change adaptation and mitigation measures.

Changes in tropospheric air quality related to the protection of stratospheric ozone in a changing climate

Ultraviolet (UV) radiation drives the net production of tropospheric ozone (O3) and a large fraction of particulate matter (PM) including sulfate, nitrate, and secondary organic aerosols. Ground-level O3 and PM are detrimental to human health, leading to several million premature deaths per year globally, and have adverse effects on plants and the yields of crops. The Montreal Protocol has prevented large increases in UV radiation that would have had major impacts on air quality. Future scenarios in which stratospheric O3 returns to 1980 values or even exceeds them (the so-called super-recovery) will tend to ameliorate urban ground-level O3 slightly but worsen it in rural areas. Furthermore, recovery of stratospheric O3 is expected to increase the amount of O3 transported into the troposphere by meteorological processes that are sensitive to climate change. UV radiation also generates hydroxyl radicals (OH) that control the amounts of many environmentally important chemicals in the atmosphere including some greenhouse gases, e.g., methane (CH4), and some short-lived ozone-depleting substances (ODSs). Recent modeling studies have shown that the increases in UV radiation associated with the depletion of stratospheric ozone over 1980-2020 have contributed a small increase (~ 3%) to the globally averaged concentrations of OH. Replacements for ODSs include chemicals that react with OH radicals, hence preventing the transport of these chemicals to the stratosphere. Some of these chemicals, e.g., hydrofluorocarbons that are currently being phased out, and hydrofluoroolefins now used increasingly, decompose into products whose fate in the environment warrants further investigation. One such product, trifluoroacetic acid (TFA), has no obvious pathway of degradation and might accumulate in some water bodies, but is unlikely to cause adverse effects out to 2100.

Neurotoxic effects of environmental contaminants-measurements, mechanistic insight, and environmental relevance

Pollution is a significant and growing concern for any population regardless of age because these environmental contaminants exhibit different neurodegenerative effects on persons of different ages. These environmental contaminants are the products of human welfare projects like industry, automobile exhaust, clinical and research laboratory extrudes, and agricultural chemicals. These contaminants are found in various forms in environmental matrices like nanoparticles, particulate matter, lipophilic vaporized toxicants, and ultrafine particulate matter. Because of their small size, they can easily cross blood-brain barriers or use different cellular mechanisms for assistance. Other than this, these contaminants cause an innate immune response in different cells of the central nervous system and cause neurotoxicity. Considering the above critiques and current needs, this review summarizes different protective strategies based on bioactive compounds present in plants. Various bioactive compounds from medicinal plants with neuroprotective capacities are discussed with relevant examples. Many in vitro studies on clinical trials have shown promising outcomes using plant-based bioactive compounds against neurological disorders.

Associations between Traffic-Related Air Pollution and Cognitive Function in Australian Urban Settings: The Moderating Role of Diabetes Status

Traffic-related air pollution (TRAP) is associated with lower cognitive function and diabetes in older adults, but little is known about whether diabetes status moderates the impact of TRAP on older adult cognitive function. We analysed cross-sectional data from 4141 adults who participated in the Australian Diabetes, Obesity and Lifestyle (AusDiab) study in 2011-2012. TRAP exposure was estimated using major and minor road density within multiple residential buffers. Cognitive function was assessed with validated psychometric scales, including: California Verbal Learning Test (memory) and Symbol-Digit Modalities Test (processing speed). Diabetes status was measured using oral glucose tolerance tests. We observed positive associations of some total road density measures with memory but not processing speed. Minor road density was not associated with cognitive function, while major road density showed positive associations with memory and processing speed among larger buffers. Within a 300 m buffer, the relationship between TRAP and memory tended to be positive in controls (β = 0.005; p = 0.062), but negative in people with diabetes (β = -0.013; p = 0.026) and negatively associated with processing speed in people with diabetes only (β = -0.047; p = 0.059). Increased TRAP exposure may be positively associated with cognitive function among urban-dwelling people, but this benefit may not extend to those with diabetes.

Hemispheric Cortical, Cerebellar and Caudate Atrophy Associated to Cognitive Impairment in Metropolitan Mexico City Young Adults Exposed to Fine Particulate Matter Air Pollution

Exposures to fine particulate matter PM_2.5 are associated with Alzheimer's, Parkinson's (AD, PD) and TDP-43 pathology in young Metropolitan Mexico City (MMC) residents. High-resolution structural T1-weighted brain MRI and/or Montreal Cognitive Assessment (MoCA) data were examined in 302 volunteers age 32.7 ± 6.0 years old. We used multivariate linear regressions to examine cortical surface area and thickness, subcortical and cerebellar volumes and MoCA in ≤30 vs. ≥31 years old. MMC residents were exposed to PM_2.5 ~ 30.9 µg/m³. Robust hemispheric differences in frontal and temporal lobes, caudate and cerebellar gray and white matter and strong associations between MoCA total and index scores and caudate bilateral volumes, frontotemporal and cerebellar volumetric changes were documented. MoCA LIS scores are affected early and low pollution controls ≥ 31 years old have higher MoCA vs. MMC counterparts (p ≤ 0.0001). Residency in MMC is associated with cognitive impairment and overlapping targeted patterns of brain atrophy described for AD, PD and Fronto-Temporal Dementia (FTD). MMC children and young adult longitudinal studies are urgently needed to define brain development impact, cognitive impairment and brain atrophy related to air pollution. Identification of early AD, PD and FTD biomarkers and reductions on PM2.5 emissions, including poorly regulated heavy-duty diesel vehicles, should be prioritized to protect 21.8 million highly exposed MMC urbanites.

A national cohort study (2000-2018) of long-term air pollution exposure and incident dementia in older adults in the United States

Air pollution may increase risk of Alzheimer’s disease and related dementias (ADRD) in the U.S., but the extent of this relationship is unclear. Here, we constructed two national U.S. population-based cohorts of those aged ≥65 from the Medicare Chronic Conditions Warehouse (2000–2018), combined with high-resolution air pollution datasets, to investigate the association of long-term exposure to ambient fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃) with dementia and AD incidence, respectively. We identified ~2.0 million incident dementia cases (N = 12,233,371; dementia cohort) and ~0.8 million incident AD cases (N = 12,456,447; AD cohort). Per interquartile range (IQR) increase in the 5-year average PM_2.5 (3.2 µg/m³), NO₂ (11.6 ppb), and warm-season O₃ (5.3 ppb) over the past 5 years prior to diagnosis, the hazard ratios (HRs) were 1.060 (95% confidence interval [CI]: 1.054, 1.066), 1.019 (95% CI: 1.012, 1.026), and 0.990 (95% CI: 0.987, 0.993) for incident dementias, and 1.078 (95% CI: 1.070, 1.086), 1.031 (95% CI: 1.023, 1.039), and 0.982 (95%CI: 0.977, 0.986) for incident AD, respectively, for the three pollutants. For both outcomes, concentration-response relationships for PM_2.5 and NO₂ were approximately linear. Our study suggests that exposures to PM_2.5 and NO₂ are associated with incidence of dementia and AD.

Air pollution has been linked to neurodegenerative disease. Here the authors carried out a population-based cohort study to investigate the association between long-term exposure to PM_2.5, NO₂, and warm-season O₃ on dementia and Alzheimer’s disease incidence in the United States.

Dementia and Major Neurocognitive Disorders: Some Lessons Learned One Century after the first Alois Alzheimer's Clinical Notes

Over 100 years ago, Alois Alzheimer presented the clinical signs and symptoms of what has been later called "Alzheimer Dementia" in a young woman whose name was Augustine Deter [...].