Ambient Air Pollution Exposure and Cerebral White Matter Hyperintensities in Older Adults: A Cross-Sectional Analysis in the Three-City Montpellier Study.

BACKGROUND: Growing epidemiological evidence suggests an adverse relationship between exposure to air pollutants and cognitive health, and this could be related to the effect of air pollution on vascular health. OBJECTIVE: We aim to evaluate the association between air pollution exposure and a magnetic resonance imaging (MRI) marker of cerebral vascular burden, white matter hyperintensities (WMH). METHODS: This cross-sectional analysis used data from the French Three-City Montpellier study. Randomly selected participants 65-80 years of age underwent an MRI examination to estimate their total and regional cerebral WMH volumes. Exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2), and black carbon (BC) at the participants' residential address during the 5 years before the MRI examination was estimated with land use regression models. Multinomial and binomial logistic regression assessed the associations between exposure to each of the three pollutants and categories of total and lobar WMH volumes. RESULTS: Participants' (n=582) median age at MRI was 70.7 years [interquartile range (IQR): 6.1], and 52% (n=300) were women. Median exposure to air pollution over the 5 years before MRI acquisition was 24.3 (IQR: 1.7) µg/m3 for PM2.5, 48.9 (14.6) µg/m3 for NO2, and 2.66 (0.60) 10-5/m for BC. We found no significant association between exposure to the three air pollutants and total WMH volume. We found that PM2.5 exposure was significantly associated with higher risk of temporal lobe WMH burden [odds ratio (OR) for an IQR increase=1.82 (95% confidence interval: 1.41, 2.36) for the second volume tercile, 2.04 (1.59, 2.61) for the third volume tercile, reference: first volume tercile]. Associations for other regional WMH volumes were inconsistent. CONCLUSION: In this population-based study in older adults, PM2.5 exposure was associated with increased risk of high WMH volume in the temporal lobe, strengthening the evidence on PM2.5 adverse effect on the brain. Further studies looking at different markers of cerebrovascular damage are still needed to document the potential vascular effects of air pollution. https://doi.org/10.1289/EHP12231.

Air quality improvement and incident dementia: Effects of observed and hypothetical reductions in air pollutant using parametric g-computation.

INTRODUCTION: No evidence exists about the impact of air pollution reduction on incidence of dementia. The aim of this study was to quantify how air quality improvement leads to dementia-incidence benefits. METHODS: In the French Three-City cohort (12 years of follow-up), we used parametric g-computation to quantify the expected number of prevented dementia cases under different hypothetical interventions with particulate matter measuring <2.5 µm (PM2.5 ) reductions. RESULTS: Among 7051 participants, 789 participants developed dementia. The median PM2.5 reduction between 1990 and 2000 was 12.2 (µg/m3 ). Such a reduction reduced the risk of all-cause dementia (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.76 to 0.95). If all study participants were enjoying a hypothetical reduction of more than 13.10 µg/m3 (median reduction observed in the city of Montpellier), the rate difference was -0.37 (95% CI, -0.57 to -0.17) and the rate ratio was 0.67 (95% CI, 0.50 to 0.84). DISCUSSION: These findings highlight the possible substantial benefits of reducing air pollution in the prevention of dementia.

Exposure to ambient air pollution and cognitive decline: Results of the prospective Three-City cohort study.

BACKGROUND: Growing epidemiological evidence suggests an adverse relationship between exposure to air pollutants and cognitive decline. However, there is still some heterogeneity in the findings, with inconsistent results depending on the pollutant and the cognitive domain considered. We wanted to determine whether air pollution was associated with global and domain-specific cognitive decline. METHODS: This analysis used data from the French Three-City prospective cohort (participants aged 65 and older at recruitment and followed for up to 12 years). A battery of cognitive tests was administered at baseline and every 2 years, to assess global cognition (Mini Mental State Examination, MMSE), visual memory (Benton Visual Retention Test), semantic fluency (Isaacs Set Test) and executive functions (Trail Making Tests A and B). Exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2) and black carbon (BC) at the participants' residential address during the 5 years before the baseline visit was estimated with land use regression models. Linear mixed models and latent process mixed models were used to assess the association of each pollutant with global and domain-specific cognitive decline. RESULTS: The participants' (n = 6380) median age was 73.4 years (IQR: 8.0), and 61.5% were women. At baseline, the median MMSE score was 28 (IQR: 3). Global cognition decline, assessed with the MMSE, was slightly accelerated among participants with higher PM2.5 exposure: one IQR increment in PM2.5 (1.5 µg/m3) was associated with accelerated decline (ß: -0.0060 [-0.0112; -0.0007] standard unit per year). Other associations were inconsistent in direction, and of small magnitude. CONCLUSION: In this large population-based cohort, higher PM2.5 exposure was associated with accelerated global cognition decline. We did not detect any significant association for the specific cognitive domains or the other pollutants. Evidence concerning PM2.5 effects on cognition is growing, but more research is needed on other ambient air pollutants.

Post-injury benzodiazepine and opioid use among older adults involved in road traffic crashes: A Swedish register-based longitudinal study.

AIM: Psychotropic drugs like opioids and benzodiazepines are prescribed for traumas resulting from road traffic crashes and the risk of developing an addiction deserves consideration. This study aims to shed light on how the consumption of those drugs evolves over time among older road traffic injury (RTI) victims. METHODS: We conducted a nationwide Swedish register-based longitudinal study to identify trajectories of post-RTI psychotropic drug use. All individuals aged 50 years and older who had a hospital visit for an RTI from 2007 to 2015 were followed up during a 2-year period; those who used the drugs prior to the RTI were excluded. Trajectories were identified by performing latent class trajectory analysis on drug dispensation data for opioids and benzodiazepines separately (66 034 and 66 859 adults, respectively, in total). RESULTS: Three trajectories were identified for opioids and four for benzodiazepines. The largest group in both instances included people with no-use/minimal use throughout the follow-up (81.3% and 92.8%). "Sporadic users" were more frequent among users of opioids (16.7%) than benzodiazepines (4.3%), whereas "chronic users" were found in similar proportions (2.0% and 1.8%). "Delayed chronic use" characterized the fourth group of benzodiazepine users (1.0%). CONCLUSION: Several trajectories of psychotropic drug use were identified after RTI, from limited to chronic. Although chronic use was uncommon, a better understanding of the factors likely to increase that risk is warranted given the seriousness of the problem.