Short-term association between environmental factors and hospital admissions due to dementia in Madrid

Road traffic noise, air pollution, and risk of dementia - results from the Betula project

BACKGROUND

There is growing evidence for a negative impact of traffic-related air pollution on risk of dementia. However, the contribution of noise exposure to this association has been rarely examined.

OBJECTIVE

We aimed to investigate the individual and combined effect of noise and air pollution on risk of dementia.

METHODS

Data on dementia incidence over a 15 year period was obtained from the Betula project, a longitudinal study on health and ageing. Estimates of annual mean levels of nitrogen oxides (NO_x) at the participants' residential address were obtained using a land-use regression model. Modelled data provided road traffic noise levels (Leq. 24 h) at the participants' residential address at baseline. Cox proportional hazard regression was used to calculate hazard ratios (HR).

RESULTS

Of 1721 participants at baseline, 302 developed dementia during the follow up period. Exposure to noise levels (Leq. 24 h) > 55 dB had no significant effect on dementia risk (HR 0.95; CI: 0.57, 1.57). Residing in the two highest quartiles of NO_x exposure was associated with an increased risk of dementia. The risk associated with NO_x was not modified by adjusting for noise. Moreover, we found no significant interaction effects between NO_x and road traffic noise on dementia risk.

CONCLUSION

We found no evidence that exposure to road traffic noise, either independently or in combination with traffic air pollution, was associated with risk of dementia in our study area. Our results suggest that pollution should be considered the main component in the association between traffic related exposures and dementia.

Ambient ozone exposure and mental health: A systematic review of epidemiological studies

BACKGROUND

An increasing number of studies have suggested adverse effects of air pollution on mental health. Given the potentially negative impacts of ozone exposure on the immune and nervous system driven from animal experiments, ozone might also affect mental health. However, no systematic synthesis of the relevant literature has been conducted yet. This paper reviews the studies that assessed the link between ozone exposure and mental health thus far.

METHODS

We followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA). PubMed, Web of Science, and EMBASE were systematically searched for epidemiological studies on ambient ozone exposure and mental or behavioral disorders according to the International Classification of Disease. The period was from January 1st, 1960 to December 14st, 2017. We evaluated the risk of bias by the Office of Health Assessment and Translation (OHAT) Approach and Navigation Guide for each included study.

RESULTS

The keyword search yielded 567 results. 31 papers met the selection criteria and were included in the review. We found only inconclusive evidence that ozone affects autism spectrum disorders, impairment of cognitive functions and dementia, depression, and suicide. The large heterogeneity of study designs, outcome definitions and study quality in general prevented us from conducting meta-analyses.

CONCLUSIONS

Current evidence for an association between ambient ozone exposure and mental health outcomes is inconclusive and further high quality studies are needed to assess any potential links given the strong biologic plausibility.

Possible Biological Mechanisms Linking Mental Health and Heat-A Contemplative Review

This review provides examples of possible biological mechanisms that could, at least partly, explain the existing epidemiological evidence of heatwave-related exacerbation of mental disease morbidity. The author reviews the complicated central processes involved in the challenge of maintaining a stable body temperature in hot environments, and the maladaptive effects of certain psychiatric medicines on thermoregulation. In addition, the author discusses some alternative mechanisms, such as interrupted functional brain connectivity and the effect of disrupted sleep, which may further increase the vulnerability of mental health patients during heatwaves.

Diurnal variation in the proinflammatory activity of urban fine particulate matter (PM 2.5) by in vitro assays

Background: Ambient particulate matter (PM) smaller than 2.5 µm in diameter (PM 2.5) undergoes diurnal changes in chemical composition due to photochemical oxidation. In this study we examine the relationships between oxidative activity and inflammatory responses associated with these diurnal chemical changes. Because secondary PM contains a higher fraction of oxidized PM species, we hypothesized that PM 2.5 collected during afternoon hours would induce a greater inflammatory response than primary, morning PM 2.5. Methods: Time-integrated aqueous slurry samples of ambient PM 2.5 were collected using a direct aerosol-into-liquid collection system during defined morning and afternoon time periods. PM 2.5 samples were collected for 5 weeks in the late summer (August-September) of 2016 at a central Los Angeles site. Morning samples, largely consisting of fresh primary traffic emissions (primary PM), were collected from 6-9am (am-PM 2.5), and afternoon samples were collected from 12-4pm (pm-PM 2.5), when PM composition is dominated by products of photochemical oxidation (secondary PM). The two diurnally phased PM 2.5 slurries (am- and pm-PM 2.5) were characterized for chemical composition and BV-2 microglia were assayed in vitro for oxidative and inflammatory gene responses. Results: Contrary to expectations, the am-PM 2.5 slurry had more proinflammatory activity than the pm-PM 2.5 slurry as revealed by nitric oxide (NO) induction, as well as the upregulation of proinflammatory cytokines IL-1β, IL-6, and CCL2 (MCP-1), as assessed by messenger RNA production. Conclusions: The diurnal differences observed in this study may be in part attributed to the greater content of transition metals and water-insoluble organic carbon (WIOC) of am-PM 2.5 (primary PM) vs. pm-PM 2.5 (secondary PM), as these two classes of compounds can increase PM 2.5 toxicity.

Diurnal variation in the proinflammatory activity of urban fine particulate matter (PM 2.5) by in vitro assays

Background: Ambient particulate matter (PM) smaller than 2.5 µm in diameter (PM 2.5) undergoes diurnal changes in chemical composition due to photochemical oxidation. In this study we examine the relationships between oxidative activity and inflammatory responses associated with these diurnal chemical changes. Because secondary PM contains a higher fraction of oxidized PM species, we hypothesized that PM 2.5 collected during afternoon hours would induce a greater inflammatory response than primary, morning PM 2.5. Methods: Time-integrated aqueous slurry samples of ambient PM 2.5 were collected using a direct aerosol-into-liquid collection system during defined morning and afternoon time periods. PM 2.5 samples were collected for 5 weeks in the late summer (August-September) of 2016 at a central Los Angeles site. Morning samples, largely consisting of fresh primary traffic emissions (primary PM), were collected from 6-9am (am-PM 2.5), and afternoon samples were collected from 12-4pm (pm-PM 2.5), when PM composition is dominated by products of photochemical oxidation (secondary PM). The two diurnally phased PM 2.5 slurries (am- and pm-PM 2.5) were characterized for chemical composition and BV-2 microglia were assayed in vitro for oxidative and inflammatory gene responses. Results: Contrary to expectations, the am-PM 2.5 slurry had more proinflammatory activity than the pm-PM 2.5 slurry as revealed by nitric oxide (NO) induction, as well as the upregulation of proinflammatory cytokines IL-1β, IL-6, and CCL2 (MCP-1), as assessed by messenger RNA production. Conclusions: The diurnal differences observed in this study may be in part attributed to the greater content of transition metals and water-insoluble organic carbon (WIOC) of am-PM 2.5 (primary PM) vs. pm-PM 2.5 (secondary PM), as these two classes of compounds can increase PM 2.5 toxicity.

Diurnal variation in the proinflammatory activity of urban fine particulate matter (PM 2.5) by in vitro assays

Background: Ambient particulate matter (PM) smaller than 2.5 µm in diameter (PM 2.5) undergoes diurnal changes in chemical composition due to photochemical oxidation. In this study we examine the relationships between oxidative activity and inflammatory responses associated with these diurnal chemical changes. Because secondary PM contains a higher fraction of oxidized PM species, we hypothesized that PM 2.5 collected during afternoon hours would induce a greater inflammatory response than primary, morning PM 2.5. Methods: Time-integrated aqueous slurry samples of ambient PM 2.5 were collected using a direct aerosol-into-liquid collection system during defined morning and afternoon time periods. PM 2.5 samples were collected for 5 weeks in the late summer (August-September) of 2016 at a central Los Angeles site. Morning samples, largely consisting of fresh primary traffic emissions (primary PM), were collected from 6-9am (am-PM 2.5), and afternoon samples were collected from 12-4pm (pm-PM 2.5), when PM composition is dominated by products of photochemical oxidation (secondary PM). The two diurnally phased PM 2.5 slurries (am- and pm-PM 2.5) were characterized for chemical composition and BV-2 microglia were assayed in vitro for oxidative and inflammatory gene responses. Results: Contrary to expectations, the am-PM 2.5 slurry had more proinflammatory activity than the pm-PM 2.5 slurry as revealed by nitric oxide (NO) induction, as well as the upregulation of proinflammatory cytokines IL-1β, IL-6, and CCL2 (MCP-1), as assessed by messenger RNA production. Conclusions: The diurnal differences observed in this study may be in part attributed to the greater content of transition metals and water-insoluble organic carbon (WIOC) of am-PM 2.5 (primary PM) vs. pm-PM 2.5 (secondary PM), as these two classes of compounds can increase PM 2.5 toxicity.

Exploring nighttime road traffic noise: A comprehensive predictive surface for Toronto, Canada

Road traffic noise can adversely impact the health of city residents, particularly when it occurs at night. The objective of this study was to evaluate nighttime traffic ambient noise in Toronto, Canada using measured and model-estimated noise levels. Road traffic noise was measured at 767 locations over 3 seasonal sampling campaigns between June 2012 and October 2013 to fully capture noise variability in Toronto. Temporal and campaign-specific spatial models, developed using the noise measurements, were used to build a final predictive surface. The surface was capable of estimating noise across the city over a 24-hr time frame. Measured and surface-estimated noise levels were compared with guidelines from the World Health Organization and the Province of Ontario to identify areas where noise may pose a health risk. Measured mean nighttime noise in Toronto exceeded World Health Organization (40 dBA) guidelines and mean daytime noise exceeded provincial (55 dBA) guidelines. The final predictive surface, incorporating spatial variables and daily cycles in noise levels, provides noise estimates geocoded for the entire study area. This tool could be used for epidemiological studies and to inform noise mitigation efforts. Based on surface-estimated noise levels during the quietest time of night (2 a.m.-2:30 a.m.), 100% of Toronto has nighttime noise exceeding 40 dBA (mean = 57 dBA, range = 49-110 dBA). A predictive surface was developed to estimate geocoded noise levels and facilitate further study of noise in Toronto. This tool can be used to assess road traffic noise, particularly at night, as an environmental health hazard.

Emergency multiple sclerosis hospital admissions attributable to chemical and acoustic pollution: Madrid (Spain), 2001-2009

INTRODUCTION

Multiple sclerosis (MS) is the most prevalent neurological disease among young adults in Spain. A number of recent studies have linked traffic-related pollution, both chemical and acoustic, to the aetiology and exacerbation of neurodegenerative diseases.

OBJECTIVE

To analyse the existence of a significant short-term association between daily emergency MS hospital admissions and chemical and acoustic pollution caused by traffic in Madrid.

METHODOLOGY

We conducted a longitudinal ecological time series study, in which the dependent variable was the number of daily emergency MS hospital admissions (ICD-9: 340) registered in Madrid from 1 January 2001 to 31 December 2009. The independent variables were daily mean concentrations (μg/m³) of PM_2.5, PM₁₀, O₃ and NO₂. Equivalent diurnal (Leqd), nocturnal (Leqn) and daily equivalent noise levels (Leq24) were also considered. In addition, we controlled for linear trends, seasonality and the autoregressive nature of the series itself. Day of the week was also added as a covariate. Significant environmental variables were determined using Poisson GLM models. Relative risk (RR) and attributable risk (AR) values were calculated for increases of 10μg/m³ in the case of chemical pollutants and 1dB(A) in noise levels.

RESULTS

While there was no association between chemical pollutants caused by traffic and MS admissions, such an association was in evidence for Leqd at lag zero. This association is linear without a threshold, with there being a level above 67dB(A) from which this effect is more pronounced. The RRs were as follows: for all Leqd values, 1.21 (95% CI: 1.16, 1.26); and for Leqd >67dB(A), 1.62 (95% CI: 1.24, 2.13).

CONCLUSION

The above results indicate that traffic noise can exacerbate MS symptoms, leading to hospital admissions due to this cause.

Effect of night-time temperatures on cause and age-specific mortality in London

Supplemental Digital Content is available in the text.

Background:

High ambient temperatures are associated with an acute increase in mortality risk. Although heat exposure during the night is anecdotally cited as being important, this has not been rigorously demonstrated in the epidemiological literature.

Methods:

We quantified the contribution of nighttime temperatures using time-series quasi-Poisson regression on cause and age-specific daily mortality in London between 1993 and 2015. Daytime and nighttime exposures were characterized by average temperatures between 9 am and 9 pm and between 4 am and 8 am, respectively, lagged by 7 days. We also examined the differential impacts of hot and cool nights preceded by very hot days. All models were adjusted for air quality, season, and day of the week. Nighttime models were additionally adjusted for daytime exposure.

Results:

Effects from nighttime exposure persisted after adjusting for daytime exposure. This was highest for stroke, RR (relative risk) = 1.65 (95% confidence interval (CI) = 1.27 to 2.14) estimated by comparing mortality risk at the 80th and 99th temperature percentiles. Compared to daytime exposure, nighttime exposure had a higher mortality risk on chronic ischemic and stroke and in the younger age groups. Respiratory mortality was most sensitive to daytime temperatures. Hot days followed by hot nights had a greater mortality risk than hot days followed by cool nights.

Conclusions:

Nighttime exposures make an additional important contribution to heat-related mortality. This impact was highest on warm nights that were preceded by a hot day, which justifies the alert criteria in heat–health warning system that is based on hot days followed by hot nights. The highest mortality risk was from stroke; targeted interventions would benefit patients most susceptible to stroke.

Clinical effects of air pollution on the central nervous system; a review

The purpose of this review is to describe recent clinical and epidemiological studies examining the adverse effects of urban air pollution on the central nervous system (CNS). Air pollution and particulate matter (PM) are associated with neuroinflammation and reactive oxygen species (ROS). These processes affect multiple CNS pathways. The conceptual framework of this review focuses on adverse effects of air pollution with respect to neurocognition, white matter disease, stroke, and carotid artery disease. Both children and older individuals exposed to air pollution exhibit signs of cognitive dysfunction. However, evidence on middle-aged cohorts is lacking. White matter injury secondary to air pollution exposure is a putative mechanism for neurocognitive decline. Air pollution is associated with exacerbations of neurodegenerative conditions such as Alzheimer's and Parkinson's diseases. Increases in stroke incidences and mortalities are seen in the setting of air pollution exposure and CNS pathology is robust. Large populations living in highly polluted environments are at risk. This review aims to outline current knowledge of air pollution exposure effects on neurological health.

Association between environmental factors and emergency hospital admissions due to Alzheimer's disease in Madrid

INTRODUCTION

There are scarce studies of time series that analysed the short-term association between emergency hospital admissions due to Alzheimer's disease (AD) and environmental factors. The objective is to analyse the effect of heat waves, noise and air pollutants on urgent hospital admissions due to AD in Madrid.

METHODS

Longitudinal ecological time series study was performed. The dependent variable was the emergency AD hospital admissions occurred in Madrid during the period 2001-2009. Independent variables were: Daily mean concentrations (μg/m3) of air pollutants (PM_2.5 and PM₁₀; O3 and NO2); maximum daily temperature (°C) and daily and night noise levels (dB(A)). Relative Risk (RR) for an increment in interquartile range, and Attributable Risk (AR) values were calculated through GLM with Poisson link.

RESULTS

Our findings indicated that only PM_2.5 concentrations at lag 2 with a RR: 1.38 (95% CI: 1.15-1.65); AR 27.5% (95% CI: 13.0-39.4); and heat wave days at lag 3 with a RR: 1.30 (95% CI: 1.12-1.52); AR 23.1% (95% CI: 10.7-34.2) were associated with AD hospital admissions.

CONCLUSION

A reduction in AD patients' exposure levels to PM_2.5 and special care of such patients during heat wave periods could result in a decrease in both emergency AD admissions and the related health care costs.