Cooling cities through urban green infrastructure: a health impact assessment of European cities.

BACKGROUND: High ambient temperatures are associated with many health effects, including premature mortality. The combination of global warming due to climate change and the expansion of the global built environment mean that the intensification of urban heat islands (UHIs) is expected, accompanied by adverse effects on population health. Urban green infrastructure can reduce local temperatures. We aimed to estimate the mortality burden that could be attributed to UHIs and the mortality burden that would be prevented by increasing urban tree coverage in 93 European cities. METHODS: We did a quantitative health impact assessment for summer (June 1-Aug 31), 2015, of the effect of UHIs on all-cause mortality for adults aged 20 years or older in 93 European cities. We also estimated the temperature reductions that would result from increasing tree coverage to 30% for each city and estimated the number of deaths that could be potentially prevented as a result. We did all analyses at a high-resolution grid-cell level (250 × 250 m). We propagated uncertainties in input analyses by using Monte Carlo simulations to obtain point estimates and 95% CIs. We also did sensitivity analyses to test the robustness of our estimates. FINDINGS: The population-weighted mean city temperature increase due to UHI effects was 1·5°C (SD 0·5; range 0·5-3·0). Overall, 6700 (95% CI 5254-8162) premature deaths could be attributable to the effects of UHIs (corresponding to around 4·33% [95% CI 3·37-5·28] of all summer deaths). We estimated that increasing tree coverage to 30% would cool cities by a mean of 0·4°C (SD 0·2; range 0·0-1·3). We also estimated that 2644 (95% CI 2444-2824) premature deaths could be prevented by increasing city tree coverage to 30%, corresponding to 1·84% (1·69-1·97) of all summer deaths. INTERPRETATION: Our results showed the deleterious effects of UHIs on mortality and highlighted the health benefits of increasing tree coverage to cool urban environments, which would also result in more sustainable and climate-resilient cities. FUNDING: GoGreenRoutes, Spanish Ministry of Science and Innovation, Institute for Global Health, UK Medical Research Council, European Union's Horizon 2020 Project Exhaustion.

The influence of pre- and postnatal exposure to air pollution and green spaces on infant's gut microbiota: Results from the MAMI birth cohort study.

BACKGROUND: Animal and human studies indicate that exposure to air pollution and natural environments might modulate the gut microbiota, but epidemiological evidence is very scarce. OBJECTIVES: To assess the potential impact of pre- and postnatal exposure to air pollution and green spaces on infant gut microbiota assembly and trajectories during the first year of life. METHODS: MAMI ("MAternal MIcrobes") birth cohort (Valencia, Spain, N = 162) was used to study the impact of environmental exposure (acute and chronic) on infant gut microbiota during the first year of life (amplicon-based 16S rRNA sequencing). At 7 days and at 1, 6 and 12 months, residential pre- and postnatal exposure to air pollutants (NO2, black carbon -BC-, PM2.5 and O3) and green spaces indicators (NDVI and area of green spaces at 300, 500 and 1000 m buffers) were obtained. For the association between exposures and alpha diversity indicators linear regression models (cross-sectional analyses) and mixed models, including individual as a random effect (longitudinal analyses), were applied. For the differential taxon analysis, the ANCOM-BC package with a log count transformation and multiple-testing corrections were used. RESULTS: Acute exposure in the first week of life and chronic postnatal exposure to NO2 were associated with a reduction in microbial alpha diversity, while the effects of green space exposure were not evident. Acute and chronic (prenatal or postnatal) exposure to NO2 resulted in increased abundance of Haemophilus, Akkermansia, Alistipes, Eggerthella, and Tyzerella populations, while increasing green space exposure associated with increased Negativicoccus, Senegalimassilia and Anaerococcus and decreased Tyzzerella and Lachnoclostridium populations. DISCUSSION: We observed a decrease in the diversity of the gut microbiota and signs of alteration in its composition among infants exposed to higher levels of NO2. Increasing green space exposure was also associated with changes in gut microbial composition. Further research is needed to confirm these findings.

Environmental health impacts and inequalities in green space and air pollution in six medium-sized European cities.

BACKGROUND: The GoGreenRoutes project aims to introduce co-created nature-based solutions (NBS) to enhance environmental quality in six medium-sized cities (Burgas, Lahti, Limerick, Tallinn, Umeå, and Versailles). We estimated the mortality and economic impacts attributed to suboptimal exposure to green space and air pollution, economic impacts, and the distribution thereof the adult population by socioeconomic status. METHODS: We retrieved data from publicly accessible databases on green space (NDVI and % Green Area), air pollution (NO2 and PM2.5) and population (≥20 years, n = 804,975) at a 250m × 250m grid-cell level, and mortality for each city for 2015. We compared baseline exposures at the grid-cell to World Health Organization's recommendations and guidelines. We applied a comparative risk assessment to estimate the mortality burden attributable to not achieving the recommendations and guidelines. We estimated attributable mortality distributions and the association with income levels. RESULTS: We found high variability in air pollution and green spaces levels. Around 60% of the population lacked green space and 90% were exposed to harmful air pollution. Overall, we estimated age-standardized mortality rates varying from 10 (Umeå) to 92 (Burgas) deaths per 100,000 persons attributable to low NDVI levels; 3 (Lahti) to 38 (Burgas) per 100,000 persons to lack of % Green Area; 1 (Umeå) to 88 (Tallinn) per 100,000 persons to exceedances of NO2 guidelines; and 1 (Umeå) to 206 (Burgas) per 100,000 persons to exceedances of PM2.5 guidelines. Lower income associated with higher or lower mortality impacts depending on whether deprived populations lived in the densely constructed, highly-trafficked city centre or greener, less polluted outskirts. CONCLUSIONS: We attributed a considerable mortality burden to lack of green spaces and higher air pollution, which was unevenly distributed across different social groups. NBS and health-promoting initiatives should consider socioeconomic aspects to regenerate urban areas while providing equally good environments.

The evaluation of the 3-30-300 green space rule and mental health.

BACKGROUND AND AIMS: Urban green space has many health benefits, but it is still unclear how much actually is needed for better health. Recently a new 3-30-300 rule of thumb for urban forestry and urban greening has been proposed, but this rule has not been evaluated for benefits on health. The rule requires that every citizen should be able to see at least three trees from their home, have 30 percent tree canopy cover in their neighbourhood and not live more than 300 m away from the nearest park or green space. The aim of this study was to evaluate the relationship between the 3-30-300 green space rule and its components in relation to mental health. METHODS: We conducted a cross-sectional study based on a population-based sample of 3145 individuals aged 15-97 years from in Barcelona, Spain who participated in the Barcelona Health Survey (2016-2017). We created 3-30-300 green space indicators using questionnaire data, GIS, remote sensing and land cover maps. Mental health status was assessed with the 12-item General Health Questionnaire (GHQ-12) and also the use of tranquilizer/sedatives or antidepressants and psychiatrist or psychologist visits. Analyses were conducted using mixed effects logistic regression models with districts as the random effect, adjusted for relevant covariates. RESULTS: We found that people in Barcelona had relatively little exposure to green space, whether through window view, living in an area with sufficient greenness, or access to a major green space, and only 4.7% met a surrogate 3-30-300 green space rule. Residential surrounding greenness, but not tree window view or access to major green space, was significantly associated with better mental health, less medication use, and fewer psychologist or psychiatrist visits. Meeting the full surrogate 3-30-300 green space rule was associated with better mental health, less medication use, and fewer psychologist or psychiatrist visits, but only for the latter combined the association was statistically significant (Odds ratio = 0.31, 95% CI: 0.11, 0.91). CONCLUSION: Few people achieved the 3-30-300 green space in Barcelona and we used a surrogate measure. We observed health benefits when the full surrogate rule was met.

Urban environment and physical activity and capacity in patients with chronic obstructive pulmonary disease.

BACKGROUND: Physical activity and exercise capacity are key prognostic factors in chronic obstructive pulmonary disease (COPD) but their environmental determinants are unknown. OBJECTIVES: To test the association between urban environment and objective physical activity, physical activity experience and exercise capacity in COPD. METHODS: We studied 404 patients with mild-to-very severe COPD from a multi-city study in Catalonia, Spain. We measured objective physical activity (step count and sedentary time) by the Dynaport MoveMonitor, physical activity experience (difficulty with physical activity) by the Clinical visit-PROactive (C-PPAC) instrument, and exercise capacity by the 6-min walk distance (6MWD). We estimated individually (geocoded to the residential address) population density, pedestrian street length, slope of terrain, and long-term (i.e., annual) exposure to road traffic noise, nitrogen dioxide (NO2) and particulate matter (PM2.5). We built single- and multi-exposure mixed-effects linear regressions with a random intercept for city, adjusting for confounders. RESULTS: Patients were 85% male, had mean (SD) age 69 (9) years and walked 7524 (4045) steps/day. In multi-exposure models, higher population density was associated with fewer steps, more sedentary time and worse exercise capacity (-507 [95% CI: 1135, 121] steps, +0.2 [0.0, 0.4] h/day and -13 [-25, 0] m per IQR). Pedestrian street length related with more steps and less sedentary time (156 [9, 304] steps and -0.1 [-0.1, 0.0] h/day per IQR). Steeper slope was associated with better exercise capacity (15 [3, 27] m per IQR). Higher NO2 levels related with more sedentary time and more difficulty in physical activity. PM2.5 and noise were not associated with physical activity or exercise capacity. DISCUSSION: Population density, pedestrian street length, slope and NO2 exposure relate to physical activity and capacity of COPD patients living in highly populated areas. These findings support the consideration of neighbourhood environmental factors during COPD management and the attention to patients with chronic diseases when developing urban and transport planning policies.

Impact of residential greenness on myocardial infarction in the population with diabetes: A sex-dependent association?

Living in urban areas with abundant greenness might provide health benefits in general population. Literature suggests that sex/gender plays a role in the association between greenness and health outcomes. But the impact of greenness in populations with moderate to high cardiovascular risk, such as persons with diabetes, is still unknown. Our aim was to evaluate the relationship between urban greenness and myocardial infarction incidence in persons with type 2 diabetes in Barcelona (Catalonia, Spain), and seek potential gender/sex differences in this association. This retrospective cohort study is based on data from the System for the Development of Research in Primary Care (SIDIAP database). We used Cox models to estimate if a 0.01 increase in Normalized Difference Vegetation Index (NDVI) at census tract level was associated to reduced risk of developing a myocardial infarction. Models were adjusted by demographic and clinical characteristics at individual level, and by environmental and socioeconomic variables at census tract level. Amongst 41,463 persons with diabetes and 154,803.85 person-years of follow-up, we observed 449 incident cases of acute myocardial infarction. For each 0.01 increment in NDVI the risk of developing a myocardial infarction decreased by 6% (Hazard Ratio, HR = 0.94; 95%CI, 0.89-0.99) in the population with diabetes. When stratifying by sex, we observed a significant association only in men (HR = 0.91; 95%CI, 0.86-0.97). People with diabetes living in urban greener areas might benefit from reduced cardiovascular risk, specially men. We observed sex/gender disparities, which could be related to different exposures and activities performed in green spaces between men and women. Further studies are needed to confirm sex/gender disparities between greenness exposure and cardiovascular outcomes. Our findings contribute to improve the health of people with diabetes who should be recommended to spent time and exercise in green areas.

Air pollution and green spaces in relation to breast cancer risk among pre and postmenopausal women: A mega cohort from Catalonia.

BACKGROUND: The association between air pollution and green spaces with breast cancer risk stratified by menopausal status has not been frequently investigated despite its importance given the different impact of risk factors on breast cancer risk depending on menopausal status. OBJECTIVES: To study the association between air pollution, green spaces and pre and postmenopausal breast cancer risk. METHODS: We conducted a population-based cohort study using electronic primary care records in Catalonia. We included women aged 17-85 years free of cancer at study entry between 2009 and 2017. Our exposures were particulate matter <2.5 µm (PM2.5) & <10 µm (PM10), nitrogen dioxide (NO2), normalized difference vegetation index (NDVI), and percentage of green spaces estimated at the census tract level. Breast cancer was identified with ICD-10 code C50. We estimated cause-specific hazard ratios (HR) for the relationship between each individual exposure and pre and postmenopausal breast cancer risk, using linear and non-linear models. RESULTS: Of the 1,054,180 pre and 744,658 postmenopausal women followed for a median of 10 years, 6,126 and 17,858 developed breast cancer, respectively. Among premenopausal women, only very high levels of PM10 (≥46 µg/m3) were associated with increased cancer risk (compared to lower levels) in non-linear models. Among postmenopausal women, an interquartile range increase in PM2.5 (HR:1.03; 95%CI:1.01-1.04), PM10 (1.03; 1.01-1.05), and NO2 (1.05; 1.02-1.08) were associated with higher cancer risk. NDVI was negatively associated with decreased cancer risk only among postmenopausal women who did not change residence during follow-up (0.84; 0.71-0.99) or who were followed for at least three years (0.82; 0.69-0.98). DISCUSSION: Living in areas with high concentrations of PM2.5, PM10, and NO2 increases breast cancer risk in postmenopausal women while long-term exposure to green spaces may decrease this risk. Only very high concentrations of PM10 increase breast cancer risk in premenopausal women.

Ambient air pollution and the development of overweight and obesity in children: a large longitudinal study.

BACKGROUND: Ambient air pollution may play a role in childhood obesity development, but evidence is scarce, and the modifying role of socioeconomic status (SES) is unclear. We aimed to examine the association between exposure to air pollution during early childhood and subsequent risk of developing overweight and obesity, and to evaluate whether SES is a modifier of this association. METHODS: This longitudinal study included 416,955 children identified as normal weight between 2-5 years old and registered in an electronic primary healthcare record between 2006 and 2016 in Catalonia (Spain). Children were followed-up until they developed overweight or obesity, reached 15 years of age, died, transferred out, or end of study period (31/12/2018). Overweight and obesity were defined following the WHO reference obtained from height and weight measures. We estimated annual residential census levels of nitrogen dioxide (NO2) and particulate matter <10 µm (PM10), <2.5 µm (PM2.5), and 2.5-10 µm (PMcoarse) at study entry. We estimated the risk of developing overweight and obesity per interquartile range increase in air pollution exposure with Cox proportional hazard models. RESULTS: A total of 142,590 (34.2%) children developed overweight or obesity. Increased exposure to NO2, PM10, and PMcoarse was associated with a 2-3% increased risk of developing overweight and obesity (hazard ratio [HR] per 21.8 µg/m3 NO2 = 1.03 [95% CI: 1.02-1.04]; HR per 6.4 µg/m3 PM10 = 1.02 [95% CI: 1.02-1.03]; HR per 4.6 µg/m3 PMcoarse = 1.02, [95% CI: 1.01-1.02]). For all air pollutants, associations were stronger among children living in most compared to least deprived areas. CONCLUSIONS: This study suggests that early life exposure to air pollution may be associated with a small increase in the risk of developing overweight and obesity in childhood, and that this association may be exacerbated in the most deprived areas. Even these small associations are of potential global health importance because air pollution exposure is widespread and the long-term health consequences of childhood obesity are clear.

The effect of short term exposure to outdoor air pollution on fertility.

BACKGROUND: There is evidence to suggest that long term exposure to air pollution could be associated with decreased levels of fertility, although there is controversy as to how short term exposure may compromise fertility in IVF patients and what windows of exposure during the IVF process patients could be most vulnerable. METHODS: This prospective cohort study aimed to evaluate the impact of acute exposure that air pollution have on reproductive outcomes in different moments of the IVF process. Women undergoing IVF living in Barcelona were recruited. Individual air pollution exposures were modelled at their home address 15 and 3 days before embryo transfer (15D and 3D, respectively), the same day of transfer (D0), and 7 days after (D7). The pollutants modelled were: PM2.5 [particulate matter (PM) ≤2.5 µm], PMcoarse (PM between 2.5 and 10µm), PM10 (PM≤10 µm), PM2.5 abs, and NO2 and NOx. Outcomes were analyzed using multi-level regression models, with adjustment for co-pollutants and confouding factors. Two sensitivity analyses were performed. First, the model was adjusted for subacute exposure (received 15 days before ET). The second analysis was based on the first transfer performed on each patient aiming to exclude patients who failed previous transfers. RESULTS: One hundred ninety-four women were recruited, contributing with data for 486 embryo transfers. Acute and subacute exposure to PMs showed a tendency in increasing miscarriage rate and reducing clinical pregnancy rate, although results were not statistically significant. The first sensitivity analysis, showed a significant risk of miscarriage for PM2.5 exposure on 3D after adjusting for subacute exposure, and an increased risk of achieving no pregnancy for PM2.5, PMcoarse and PM10 on 3D. The second sensitivity analysis showed a significant risk of miscarriage for PM2.5 exposure on 3D, and a significant risk of achieving no pregnancy for PM2.5, PMcoarse and PM10 particularly on 3D. No association was observed for nitrogen dioxides on reproductive outcomes. CONCLUSIONS: Exposure to particulate matter has a negative impact on reproductive outcomes in IVF patients. Subacute exposure seems to increase the harmful effect of the acute exposure on miscarriage and pregnancy rates. Nitrogen dioxides do not modify significantly the reproductive success.

Residential urban greenspace and hypertension: A comparative study in two European cities.

BACKGROUND: Living in green areas has been associated with several health benefits; however, the available evidence on such benefits for hypertension is still limited. This study aimed to investigate and compare the association between residential exposure to greenspace and hypertension in Barcelona, Spain and Brussels, Belgium. METHODS: This cross-sectional study was based on data from the 2016 Barcelona Health Interview Survey (HIS) (n = 3400) and the 2013 Belgian HIS (n = 2335). Both surveys were harmonized in terms of outcomes, confounders and exposure assessment. Residential exposure to greenspace was characterized as 1) surrounding greenspace (normalized difference vegetation index (NDVI) and modified soil-adjusted vegetation index 2 (MSAVI2)) across buffers of 100 m, 300 m, and 500 m; 2) surrounding green space across 300 m and 500 m buffers; and 3) Euclidean distance to the nearest green space. Our outcome was self-reported hypertension. We developed logistic regression models to evaluate the city-specific association between each greenspace measure and hypertension, adjusting for relevant covariates. RESULTS: One interquartile range (IQR) increase in residential distance to the nearest green space was associated with higher risk of hypertension in Barcelona [odds ratio (OR): 1.15; 95%CI 1.03-1.29 (IQR: 262.2)], but not in Brussels [OR: 0.95; 95%CI 0.77-1.17 (IQR: 215.2)]. Stratified analyses suggested stronger associations in older participants (≥65 years) for both cities. Findings for residential surrounding green space and greenspace were not conclusive. However, in Brussels, we found protective associations in older participants for both residential surrounding greenspace metrics [NDVI 300 m buffer OR: 0.51; 95%CI 0.32-0.81 (IQR: 0.21) and MSAVI2 300 m buffer OR: 0.51; 95%CI 0.32-0.83 (IQR: 0.18)]. We did not find any indication for the modification of our evaluated associations by sex and education level. CONCLUSION: Our study suggests that living closer to greenspace could be associated with lower risk of hypertension, particularly in older age. Future research is needed to replicate our findings in other settings and shed light on potential underlying mechanism(s).

Outdoor air pollution and the burden of childhood asthma across Europe.

BACKGROUND: Emerging evidence suggests that air pollution may contribute to childhood asthma development. We estimated the burden of incident childhood asthma that may be attributable to outdoor nitrogen dioxide (NO2), particulate matter ≤2.5 µm in diameter (PM2.5) and black carbon (BC) in Europe. METHODS: We combined country-level childhood incidence rates and pooled exposure-response functions with childhood (age 1-14 years) population counts, and exposure estimates at 1 540 386 1 km×1 km cells, across 18 European countries and 63 442 419 children. Annual average pollutant concentrations were obtained from a validated and harmonised European land-use regression model. We investigated two exposure reduction scenarios. For the first, we used recommended annual World Health Organization (WHO) air quality guideline values. For the second, we used the minimum air pollution levels recorded across 41 studies in the underlying meta-analysis. RESULTS: NO2 ranged from 1.4 to 70.0 µg·m-3, with a mean of 11.8 µg·m-3. PM2.5 ranged from 2.0 to 41.1 µg·m-3, with a mean of 11.6 µg·m-3. BC ranged from 0.003 to 3.7×10-5 m-1, with a mean of 1.0×10-5 m-1. Compliance with the NO2 and PM2.5 WHO guidelines was estimated to prevent 2434 (0.4%) and 66 567 (11%) incident cases, respectively. Meeting the minimum air pollution levels for NO2 (1.5 µg·m-3), PM2.5 (0.4 µg·m-3) and BC (0.4×10-5 m-1) was estimated to prevent 135 257 (23%), 191 883 (33%) and 89 191 (15%) incident cases, respectively. CONCLUSIONS: A significant proportion of childhood asthma cases may be attributable to outdoor air pollution and these cases could be prevented. Our estimates underline an urgent need to reduce children's exposure to air pollution.

Effects of prenatal exposure to particulate matter air pollution on corpus callosum and behavioral problems in children.

OBJECTIVE: Air pollution (AP) may affect neurodevelopment, but studies about the effects of AP on the growing human brain are still scarce. We aimed to investigate the effects of prenatal exposure to AP on lateral ventricles (LV) and corpus callosum (CC) volumes in children and to determine whether the induced brain changes are associated with behavioral problems. METHODS: Among the children recruited through a set of representative schools of the city of Barcelona, (Spain) in the Brain Development and Air Pollution Ultrafine Particles in School Children (BREATHE) study, 186 typically developing participants aged 8-12 years underwent brain MRI on the same 1.5 T MR unit over a 1.5-year period (October 2012-April 2014). Brain volumes were derived from structural MRI scans using automated tissue segmentation. Behavioral problems were assessed using the Strengths and Difficulties Questionnaire (SDQ) and the criteria of the Attention Deficit Hyperactivity Disorder DSM-IV list. Prenatal fine particle (PM2.5) levels were retrospectively estimated at the mothers' residential addresses during pregnancy with land use regression (LUR) models. To determine whether brain structures might be affected by prenatal PM2.5 exposure, linear regression models were run and adjusted for age, sex, intracranial volume (ICV), maternal education, home socioeconomic vulnerability index, birthweight and mothers' smoking status during pregnancy. To test for associations between brain changes and behavioral outcomes, negative binomial regressions were performed and adjusted for age, sex, ICV. RESULTS: Prenatal PM2.5 levels ranged from 11.8 to 39.5 µg/m3 during the third trimester of pregnancy. An interquartile range increase in PM2.5 level (7 µg/m3) was significantly linked to a decrease in the body CC volume (mm3) (ß = -53.7, 95%CI [-92.0, -15.5] corresponding to a 5% decrease of the mean body CC volume) independently of ICV, age, sex, maternal education, socioeconomic vulnerability index at home, birthweight and mothers' smoking status during the third trimester of pregnancy. A 50 mm3 decrease in the body CC was associated with a significant higher hyperactivity subscore (Rate Ratio (RR) = 1.09, 95%CI [1.01, 1.17) independently of age, sex and ICV. The statistical significance of these results did not survive to False Discovery Rate correction for multiple comparisons. CONCLUSIONS: Prenatal exposure to PM2.5 may be associated with CC volume decrease in children. The consequences might be an increase in behavioral problems.

Association of residential air pollution, noise, and greenspace with initial ischemic stroke severity.

BACKGROUND AND PURPOSE: A number of environmental risk factors of acute ischemic stroke have been identified, but few studies have evaluated the influence of the outdoor environment on stroke severity. We assessed the association of residential ambient fine particulate matter air pollution (PM2.5), noise, and surrounding greenspace with initial stroke severity. METHODS: We obtained data on patients hospitalized with acute ischemic stroke from a hospital-based prospective stroke register (2005-2014) in Barcelona. We estimated residential PM2.5 based on an established land use regression model, greenspace as the average satellite-based Normalized Difference Vegetation Index (NDVI) within a 300 m buffer of the residence, and daily (Lday), evening (Levening), night (Lnight) and average noise (Lden) level at the street nearest to the residential address using municipal noise models. Stroke severity was assessed at the time of hospital presentation using the National Institute of Health Stroke Scale (NIHSS).We used logistic regression and binomial models to evaluate the associations of PM2.5, greenspace, and noise with initial stroke severity adjusting for potential confounders. RESULTS: Among 2761 patients, higher residential surrounding greenspace was associated with lower risk of severe stroke (OR for NIHSS>5, 0.75; 95% CI: 0.60-0.95), while, living in areas with higher Lden was associated with a higher risk of severe stroke (OR, 1.30; 95% CI: 1.02-1.65). PM2.5 was not associated with initial stroke severity. CONCLUSIONS: In an urban setting, surrounding greenspace and traffic noise at home are associated with initial stroke severity, suggesting an important influence of the built environment on the global burden of ischemic stroke.

Long-term exposure to residential green and blue spaces and anxiety and depression in adults: A cross-sectional study.

BACKGROUND: Although exposure to natural outdoor environments has been consistently associated with improved perceived general health, available evidence on a protective association between this exposure and specific mental health disorders such as depression and anxiety is still limited. OBJECTIVE: The aim of this study was to evaluate the effects of long-term exposure to residential green and blue spaces on anxiety and depression and intake of related medication. Additionally, we aimed to explore potential mediators and effect modifiers of this association. METHODS: The study was based on an existing adult cohort (ALFA - Alzheimer and Families) and includes 958 adult participants from Barcelona recruited in 2013-2014. For each participant residential green and blue exposure indicators [surrounding greenness (NDVI), amount of green (land-cover) and access to major green spaces and blue spaces] were generated for different buffers (100m, 300m and 500m). Participants reported their history of doctor-diagnosed anxiety and depressive disorders and intake of related medication. Logistic regression models were applied to assess the corresponding associations. RESULTS: Increasing surrounding greenness was associated with reduced odds of self-reported history of benzodiazepines [e.g. Odds ratio - OR (95%CI) = 0.62 (0.43, 0.89) for 1-interquartile range (IQR) increase in NDVI in a 300m buffer] and access to major green spaces was associated with self-reported history of depression [OR (95%CI) = 0.18 (0.06, 0.58)]. No statistically significant associations were observed with blue spaces. Air pollution (between 0.8% and 29.6%) and noise (between 2.2% and 5.3%) mediated a proportion of the associations observed, whereas physical activity and social support played a minor role. CONCLUSION: Our findings suggest a potential protective role of green spaces on mental health (depression and anxiety) in adults, but further studies, especially longitudinal studies, are needed to provide further evidence of these benefits and of the mediation role of exposures like air pollution and noise.

Short-term exposure to traffic-related air pollution and ischemic stroke onset in Barcelona, Spain.

OBJECTIVE: To assess the relationship between short-term exposure to outdoor ambient air pollutants (fine particulate matter [PM2.5] and black carbon [BC]), ischemic stroke (IS) and its different subtypes, and the potential modifying effect of neighborhood greenspace and noise. METHODS: This time-stratified case-crossover study was based on IS and transient ischemic attacks (TIA) recorded in a hospital-based prospective stroke register (BASICMAR 2005-2014) in Barcelona (Catalonia, Spain). Daily and hourly pollutant concentrations and meteorological data were obtained from monitoring stations in the city. Time-lags (from previous 72h to acute stroke onset) were analyzed. Greenness and noise were determined from the Normalized Difference Vegetation Index (NDVI) and daily average noise level at the street nearest to residential address, respectively. RESULTS: The 2742 cases with known onset date and time, living in the study area, were analyzed. After adjusting for temperature, no statistically significant association between pollutants exposure and overall stroke risk was found. In subtype analysis, an association was detected between BC exposure at 24-47h (odds ratio, 1.251; 95% confidence interval [CI], 1.001-1.552; P = 0.042) and 48-72h (1.211; 95% CI, 0.988-1.484; P = 0.065) time-lag prior to stroke onset and large-artery atherosclerosis subtype. No clear modifying effect of greenness or noise was observed. CONCLUSIONS: Overall, no association was found between PM2.5 and BC exposure and acute IS risk. By stroke subtype, large-artery atherosclerotic stroke could be triggered by daily increases in BC, a diesel fuel-related pollutant in the study area.

Land use regression models for the oxidative potential of fine particles (PM2.5) in five European areas.

Oxidative potential (OP) of particulate matter (PM) is proposed as a biologically-relevant exposure metric for studies of air pollution and health. We aimed to evaluate the spatial variability of the OP of measured PM2.5 using ascorbate (AA) and (reduced) glutathione (GSH), and develop land use regression (LUR) models to explain this spatial variability. We estimated annual average values (m-3) of OPAA and OPGSH for five areas (Basel, CH; Catalonia, ES; London-Oxford, UK (no OPGSH); the Netherlands; and Turin, IT) using PM2.5 filters. OPAA and OPGSH LUR models were developed using all monitoring sites, separately for each area and combined-areas. The same variables were then used in repeated sub-sampling of monitoring sites to test sensitivity of variable selection; new variables were offered where variables were excluded (p > .1). On average, measurements of OPAA and OPGSH were moderately correlated (maximum Pearson's maximum Pearson's R = = .7) with PM2.5 and other metrics (PM2.5absorbance, NO2, Cu, Fe). HOV (hold-out validation) R2 for OPAA models was .21, .58, .45, .53, and .13 for Basel, Catalonia, London-Oxford, the Netherlands and Turin respectively. For OPGSH, the only model achieving at least moderate performance was for the Netherlands (R2 = .31). Combined models for OPAA and OPGSH were largely explained by study area with weak local predictors of intra-area contrasts; we therefore do not endorse them for use in epidemiologic studies. Given the moderate correlation of OPAA with other pollutants, the three reasonably performing LUR models for OPAA could be used independently of other pollutant metrics in epidemiological studies.

The Influence of Meteorological Factors and Atmospheric Pollutants on the Risk of Preterm Birth.

Atmospheric pollutants and meteorological conditions are suspected to be causes of preterm birth. We aimed to characterize their possible association with the risk of preterm birth (defined as birth occurring before 37 completed gestational weeks). We pooled individual data from 13 birth cohorts in 11 European countries (71,493 births from the period 1994-2011, European Study of Cohorts for Air Pollution Effects (ESCAPE)). City-specific meteorological data from routine monitors were averaged over time windows spanning from 1 week to the whole pregnancy. Atmospheric pollution measurements (nitrogen oxides and particulate matter) were combined with data from permanent monitors and land-use data into seasonally adjusted land-use regression models. Preterm birth risks associated with air pollution and meteorological factors were estimated using adjusted discrete-time Cox models. The frequency of preterm birth was 5.0%. Preterm birth risk tended to increase with first-trimester average atmospheric pressure (odds ratio per 5-mbar increase = 1.06, 95% confidence interval: 1.01, 1.11), which could not be distinguished from altitude. There was also some evidence of an increase in preterm birth risk with first-trimester average temperature in the -5°C to 15°C range, with a plateau afterwards (spline coding, P = 0.08). No evidence of adverse association with atmospheric pollutants was observed. Our study lends support for an increase in preterm birth risk with atmospheric pressure.

Urban green and grey space in relation to respiratory health in children.

We assessed the effect of three different indices of urban built environment on allergic and respiratory conditions.This study involved 2472 children participating in the ongoing INMA birth cohort located in two bio-geographic regions (Euro-Siberian and Mediterranean) in Spain. Residential surrounding built environment was characterised as 1) residential surrounding greenness based on satellite-derived normalised difference vegetation index (NDVI), 2) residential proximity to green spaces and 3) residential surrounding greyness based on urban land use patterns. Information on wheezing, bronchitis, asthma and allergic rhinitis up to age 4 years was obtained from parent-completed questionnaires. Logistic regression and generalised estimating equation modelling were performed.Among children from the Euro-Siberian region, higher residential surrounding greenness and higher proximity to green spaces were negatively associated with wheezing. In the Mediterranean region, higher residential proximity to green spaces was associated with a reduced risk for bronchitis. A higher amount of residential surrounding greyness was found to increase the risk for bronchitis in this region.Associations between indices of urban residential greenness and greyness with respiratory diseases differ by region. The pathways underlying these associations require further exploration.

Land Use Regression Models for Ultrafine Particles in Six European Areas.

Long-term ultrafine particle (UFP) exposure estimates at a fine spatial scale are needed for epidemiological studies. Land use regression (LUR) models were developed and evaluated for six European areas based on repeated 30 min monitoring following standardized protocols. In each area; Basel (Switzerland), Heraklion (Greece), Amsterdam, Maastricht, and Utrecht ("The Netherlands"), Norwich (United Kingdom), Sabadell (Spain), and Turin (Italy), 160-240 sites were monitored to develop LUR models by supervised stepwise selection of GIS predictors. For each area and all areas combined, 10 models were developed in stratified random selections of 90% of sites. UFP prediction robustness was evaluated with the intraclass correlation coefficient (ICC) at 31-50 external sites per area. Models from Basel and The Netherlands were validated against repeated 24 h outdoor measurements. Structure and model R2 of local models were similar within, but varied between areas (e.g., 38-43% Turin; 25-31% Sabadell). Robustness of predictions within areas was high (ICC 0.73-0.98). External validation R2 was 53% in Basel and 50% in The Netherlands. Combined area models were robust (ICC 0.93-1.00) and explained UFP variation almost equally well as local models. In conclusion, robust UFP LUR models could be developed on short-term monitoring, explaining around 50% of spatial variance in longer-term measurements.

Longitudinal association between air pollution exposure at school and cognitive development in school children over a period of 3.5 years.

INTRODUCTION: Recently, we showed that exposure to traffic-related air pollutants (TRAPs) at school was negatively associated with cognitive development, specifically working memory and inattentiveness, in primary schoolchildren during a course of 12 months. The persistence of such associations over longer periods remains as an open question. OBJECTIVE: To study the longitudinal association between TRAPs at school and cognitive development over a period of 3.5 years. METHODS: Indoor and outdoor levels of TRAPs (elemental carbon (EC), dioxide nitrogen (NO2), particulate matter (PM2.5) from traffic sources and ultrafine particles (UFP)) were measured at 39 schools across Barcelona during 2012/2013. Working memory, as a measure of cognitive development, was evaluated 4 times in 2012/2013 assessment and was re-evaluated one more time in 2015 using computerized n-back test (3-back d' as main outcome). Linear mixed effects models were used to test the association between TRAPs and 3-back d', adding child and school as random effects to account for the multilevel nature of the data, and school air pollutants levels (one at a time) as predictor. RESULTS: We found detrimental associations between all TRAPs and annual change in 3-back d' (working memory) (i.e. slower development of working memory in children attending schools with higher levels of air pollution). The associations (per one interquartile range increase in exposure) were strongest for outdoor NO2 (Coefficient (Coef) = - 4.22, 95% confidence interval (CI), - 6.22, - 2.22) and indoor UFP (Coef = - 4.12, 95%CI, - 5.68, - 1.83). These reductions were equivalent to - 20% (95%CI, - 30.1, - 10.7) and - 19.9% (95%CI, - 31.5, - 8.4) change in annual working memory development associated with one interquartile range increase in outdoor NO2 and indoor UFP, respectively. CONCLUSION: Our findings suggest the persistence of the negative association between TRAPs exposure at school and cognitive trajectory measured by n-back test over a period of 3.5 years.