Els efectes de la contaminació en les persones : què en sabem i de què busquem evidències?

En aquest article es descriu el problema de la contaminació atmosfèrica centrant-se en els efectes que produeix en la salut humana. Així, descriu breument què és la contaminació, per què ens pot afectar, i quina evidència hi ha dels problemes de salut que pot causar. L'article resumeix efectes establerts, com els respiratoris i cardiovasculars, i d'altres que són àrees actives de recerca, com els possibles efectes cognitius. En aquest darrer cas, es resumeixen els resultats d'un estudi que es va dur a terme recentment a Barcelona i es descriuen els objectius d'un nou projecte que està en fase de preparació.This article describes the problem of air pollution focusing on the effects that it has on human health. We describe briefly what air pollution is, why it can affect us, and what evidences there are about the human health problems it can cause. This article summarizes which health effects are well established, e.g. the effects on respiratory and cardiovascular diseases, and which others are an emerging research field, e.g. cognitive effects. Finally, we describe some results of a study that was recently carried out in Barcelona and the objectives of new research project that is just starting

Nivell socieconòmic i prevalença d'asma en adults joves : un anàlisi multinivell en l'European Community Respiratory Health Survey

En aquest projecte final de carrera es presenta una part d'un estudi que encara no ha estat publicat que investiga la relació entre asma i nivell socioeconòmic, és a dir, si,per exemple, són les classes socials més baixes o més pobres les que pateixen més asma. Aquest aspecte encara no havia estat tocat per l'estudi ECRHS, i altres estudis que han investigat el tema no arriben a conclusions clares. A l'IMIM estem treballant actualment en la redacció d'un article sobre això, que inclourà part de les anàlisis que es presenten en aquest projecte final de carrera però que abarcarà també una diferenciació dels diversos tipus d'asma, com per exemple l'asma al·lèrgic o el no al·lèrgic. Aquestes anàlisis addicionals no estan inclosos en aquest projecte final de carrera perquè augmentarien molt la quantitat de treball i allargarien la finalització del projecte, i a canvi no aportarien cap novetat en termes d'anàlisi ja que la metodologia que es fa servir és la mateixa però fent servir altres variables resposta

Nivell socieconòmic i prevalença d'asma en adults joves : un anàlisi multinivell en l'European Community Respiratory Health Survey

En aquest projecte final de carrera es presenta una part d'un estudi que encara no ha estat publicat que investiga la relació entre asma i nivell socioeconòmic, és a dir, si,per exemple, són les classes socials més baixes o més pobres les que pateixen més asma. Aquest aspecte encara no havia estat tocat per l'estudi ECRHS, i altres estudis que han investigat el tema no arriben a conclusions clares. A l'IMIM estem treballant actualment en la redacció d'un article sobre això, que inclourà part de les anàlisis que es presenten en aquest projecte final de carrera però que abarcarà també una diferenciació dels diversos tipus d'asma, com per exemple l'asma al·lèrgic o el no al·lèrgic. Aquestes anàlisis addicionals no estan inclosos en aquest projecte final de carrera perquè augmentarien molt la quantitat de treball i allargarien la finalització del projecte, i a canvi no aportarien cap novetat en termes d'anàlisi ja que la metodologia que es fa servir és la mateixa però fent servir altres variables resposta

Suport no presencial per l'aprenentatge de regressió lineal simple

L'objectiu final del programa és que al finalitzar l'aplicació l'usuari sigui capaç de crear els seus propis models de regressió lineal simple, que sàpiga validar-los i que en conegui les limitacions

Suport no presencial per l'aprenentatge de regressió lineal simple

L'objectiu final del programa és que al finalitzar l'aplicació l'usuari sigui capaç de crear els seus propis models de regressió lineal simple, que sàpiga validar-los i que en conegui les limitacions

Conditional poisson regression with random effects for the analysis of multi-site time series studies

The analysis of time series studies linking daily counts of a health indicator with environmental variables (e.g., mortality or hospital admissions with air pollution concentrations or temperature; or motor vehicle crashes with temperature) is usually conducted with Poisson regression models controlling for long-term and seasonal trends using temporal strata. When the study includes multiple zones, analysts usually apply a two-stage approach: first, each zone is analyzed separately, and the resulting zone-specific estimates are then combined using meta-analysis. This approach allows zone-specific control for trends. A one-stage approach uses spatio-temporal strata and could be seen as a particular case of the case–time series framework recently proposed. However, the number of strata can escalate very rapidly in a long time series with many zones. A computationally efficient alternative is to fit a conditional Poisson regression model, avoiding the estimation of the nuisance strata. To allow for zone-specific effects, we propose a conditional Poisson regression model with a random slope, although available frequentist software does not implement this model. Here, we implement our approach in the Bayesian paradigm, which also facilitates the inclusion of spatial patterns in the effect of interest. We also provide a possible extension to deal with overdispersed data. We first introduce the equations of the framework and then illustrate their application to data from a previously published study on the effects of temperature on the risk of motor vehicle crashes. We provide R code and a semi-synthetic dataset to reproduce all analyses presented.We acknowledge support from the grant CEX2018- 000806-S funded by MCIN/AEI/ 10.13039/501100011033, support from Ministry of Research and Universities of the Government of Catalonia (2021 SGR 01563) and support from the Generalitat de Catalunya through the CERCA Program.Peer ReviewedPostprint (published version

Natural outdoor environments and mental and physical health: Relationships and mechanisms

Background Evidence is growing for the beneficial impacts of natural outdoor environments on health. However, most of the evidence has focused on green spaces and little evidence is available on health benefits of blue spaces and about possible mediators and modifiers of such impacts. We investigated the association between natural outdoor environments (separately for green and blue spaces) and health (general and mental) and its possible mediators and modifiers. Methods Cross-sectional data from adults interviewed in Catalonia (Spain) between 2010 and 2012 as part of the Catalonia Health Survey were used. The collected data included sociodemographic characteristics, self-perceived general health, mental health, physical activity and social support. Indicators of surrounding greenness and access to natural outdoor environments within 300 m of the residence and degree of urbanization were derived for residential addresses. Associations were estimated using logistic regression and negative binominal models. Results Green spaces were associated with better self-perceived general health and better mental health, independent of degree of urbanization. The associations were more consistent for surrounding greenness than for access to green spaces. The results were consistent for different buffers, and when stratifying for socioeconomic status. Slightly stronger associations were found for women and residents of non-densely populated areas. No association was found between green spaces and social contacts and physical activity. The results for blue spaces were not conclusive. Conclusion Green spaces are associated with better general and mental health across strata of urbanization, socioeconomic status, and genders. Mechanisms other than physical activity or social support may explain these associations

Short-term NO2 exposure and cognitive and mental health : A panel study based on a citizen science project in Barcelona, Spain

Background The association between short-term exposure to air pollution and cognitive and mental health has not been thoroughly investigated so far. Objectives We conducted a panel study co-designed with citizens to assess whether air pollution can affect attention, perceived stress, mood and sleep quality. Methods From September 2020 to March 2021, we followed 288 adults (mean age = 37.9 years; standard deviation = 12.1 years) for 14 days in Barcelona, Spain. Two tasks were self-administered daily through a mobile application: the Stroop color-word test to assess attention performance and a set of 0-to-10 rating scale questions to evaluate perceived stress, well-being, energy and sleep quality. From the Stroop test, three outcomes related to selective attention were calculated and z-score-transformed: response time, cognitive throughput and inhibitory control. Air pollution was assessed using the mean nitrogen dioxide (NO2) concentrations (mean of all Barcelona monitoring stations or using location data) 12 and 24 h before the tasks were completed. We applied linear regression with random effects by participant to estimate intra-individual associations, controlling for day of the week and time-varying factors such as alcohol consumption and physical activity. Results Based on 2,457 repeated attention test performances, an increase of 30 μg/m3 exposure to NO2 12 h was associated with lower cognitive throughput (beta = −0.08, 95% CI: −0.15, −0.01) and higher response time (beta = 0.07, 95% CI: 0.01, 0.14) (increase inattentiveness). Moreover, an increase of 30 μg/m3 exposure to NO2 12 h was associated with higher self-perceived stress (beta = 0.44, 95% CI: 0.13, 0.77). We did not find statistically significant associations with inhibitory control and subjective well-being. Conclusions Our findings suggest that short-term exposure to air pollution could have adverse effects on attention performance and perceived stress in adults

Disentangling the effects of traffic-related noise and air pollution on blood pressure: indoor noise levels and protections

Outdoor road traffic noise levels are associated with hypertension (HT). Studies on blood pressure (BP) are inconsistent and the true indoor traffic noise exposure may differ due to protections against noise. We analysed the effects of long-term exposure to outdoor and indoor traffic noise levels on HT, systolic (SBP) and diastolic BP (DBP, mmHg), adjusting for outdoor annual average concentrations of near-road traffic-related air pollution (nitrogen dioxide, NO2) among 1926 participants (aged 36-82) from the Catalan REGICOR study. Long-term outdoor residential levels of traffic noise at night (Lnight, in A-weighted dB) and annual averages of NO2 (in µg/m3 ) were estimated at the postal addresses’ façades with a city-specific noise model and a land-use regression model, respectively. Indoor traffic noise was calculated from outdoor noise levels subtracting the attenuations in dB according to reported noise protections. Median noise levels were 56.7 dB outdoors and 27.1 dB indoors. Spearman correlations between outdoor and indoor noise with NO2 were 0.75 and 0.23, respectively. Outdoor noise was only associated with HT (OR=1.19, 95%CI: 1.02, 1.40), whereas there was a suggestive association of indoor noise with both HT (OR=1.06, 95%CI: 0.99, 1.13) and SBP (ß=0.38, 95%CI: -0.08, 0.83) per 5 dB increase in outdoor noise levels. NO2 was also associated with both outcomes after adjustment for indoor noise. Findings for indoor traffic noise levels are more plausible than those for outdoor traffic noise. The use of indoor traffic noise estimates help to disentangle the effects from those of traffic-related air pollution.Postprint (author's final draft

Green spaces and cognitive development in primary schoolchildren

© 2015, National Academy of Sciences. All rights reserved. Exposure to green space has been associated with better physical and mental health. Although this exposure could also influence cognitive development in children, available epidemiological evidence on such an impact is scarce. This study aimed to assess the association between exposure to green space and measures of cognitive development in primary schoolchildren. This study was based on 2,593 schoolchildren in the second to fourth grades (7-10 y) of 36 primary schools in Barcelona, Spain (2012-2013). Cognitive development was assessed as 12-mo change in developmental trajectory of working memory, superior working memory, and inattentiveness by using four repeated (every 3 mo) computerized cognitive tests for each outcome. We assessed exposure to green space by characterizing outdoor surrounding greenness at home and school and during commuting by using high-resolution (5 m x5 m) satellite data on greenness (normalized difference vegetation index). Multilevel modeling was used to estimate the associations between green spaces and cognitive development. We observed an enhanced 12-mo progress in working memory and superior working memory and a greater 12-mo reduction in inattentiveness associated with greenness within and surrounding school boundaries and with total surrounding greenness index (including greenness surrounding home, commuting route, and school). Adding a traffic-related air pollutant (elemental carbon) to models explained 20-65% of our estimated associations between school greenness and 12-mo cognitive development. Our study showed a beneficial association between exposure to green space and cognitive development among schoolchildren that was partly mediated by reduction in exposure to air pollution