Sophia Rodopoulou

Associations between Fine and Coarse Particles and Mortality in Mediterranean Cities: Results from the MED-PARTICLES Project

Background: Few studies have investigated the independent health effects of different size fractions of particulate matter (PM) in multiple locations, especially in Europe. Objectives: We estimated the short-term effects of PM with aerodynamic diameter ≤ 10 μm (PM10), ≤ 2.5 μm (PM2.5), and between 2.5 and 10 μm (PM2.5–10) on all-cause, cardiovascular, and respiratory mortality in 10 European Mediterranean metropolitan areas within the MED-PARTICLES project. Methods: We analyzed data from each city using Poisson regression models, and combined city-specific estimates to derive overall effect estimates. We evaluated the sensitivity of our estimates to co-pollutant exposures and city-specific model choice, and investigated effect modification by age, sex, and season. We applied distributed lag and threshold models to investigate temporal patterns of associations. Results: A 10-μg/m3 increase in PM2.5 was associated with a 0.55% (95% CI: 0.27, 0.84%) increase in all-cause mortality (0–1 day cumulative lag), and a 1.91% increase (95% CI: 0.71, 3.12%) in respiratory mortality (0–5 day lag). In general, associations were stronger for cardiovascular and respiratory mortality than all-cause mortality, during warm versus cold months, and among those ≥ 75 versus < 75 years of age. Associations with PM2.5–10 were positive but not statistically significant in most analyses, whereas associations with PM10 seemed to be driven by PM2.5. Conclusions: We found evidence of adverse effects of PM2.5 on mortality outcomes in the European Mediterranean region. Associations with PM2.5–10 were positive but smaller in magnitude. Associations were stronger for respiratory mortality when cumulative exposures were lagged over 0–5 days, and were modified by season and age.

Air pollution and hospital emergency room and admissions for cardiovascular and respiratory diseases in Doña Ana County, New Mexico.

INTRODUCTION Doña Ana County in New Mexico regularly experiences severe air pollution episodes associated with windblown dust and fires. Residents of Hispanic/Latino origin constitute the largest population group in the region. We investigated the associations of ambient particulate matter and ozone with hospital emergency room and admissions for respiratory and cardiovascular visits in adults. METHODS We used trajectories regression analysis to determine the local and regional components of particle mass and ozone. We applied Poisson generalized models to analyze hospital emergency room visits and admissions adjusted for pollutant levels, humidity, temperature and temporal and seasonal effects. RESULTS We found that the sources within 500km of the study area accounted for most of particle mass and ozone concentrations. Sources in Southeast Texas, Baja California and Southwest US were the most important regional contributors. Increases of cardiovascular emergency room visits were estimated for PM10 (3.1% (95% CI: -0.5 to 6.8)) and PM10-2.5 (2.8% (95% CI: -0.2 to 5.9)) for all adults during the warm period (April-September). When high PM10 (>150μg/m(3)) mass concentrations were excluded, strong effects for respiratory emergency room visits for both PM10 (3.2% (95% CI: 0.5-6.0)) and PM2.5 (5.2% (95% CI: -0.5 to 11.3)) were computed. CONCLUSIONS Our analysis indicated effects of PM10, PM2.5 and O3 on emergency room visits during the April-September period in a region impacted by windblown dust and wildfires.

The risks of acute exposure to black carbon in Southern Europe: results from the MED-PARTICLES project

Objectives While several studies have reported associations of daily exposures to PM2.5 (particles less than 2.5 µm) with mortality, few studies have examined the impact of its constituents such as black carbon (BC), which is also a significant contributor to global climate change. Methods We assessed the association between daily concentrations of BC and total, cardiovascular and respiratory mortality in two southern Mediterranean cities. Daily averages of BC were collected for 2 years in Barcelona, Spain and Athens, Greece. We used case-crossover analysis and examined single and cumulative lags up to 3 days. Results We observed associations between BC and all mortality measures. For a 3-day moving average, cardiovascular mortality increased by 4.5% (95% CI 0.7 to 8.5) and 2.0% (95% CI 0 to 4.0) for an interquartile change in BC in Athens and Barcelona, respectively. Considerably higher effects for respiratory mortality and for those above age 65 were observed. In addition, BC exhibited much greater toxicity per microgram than generic PM2.5. Conclusions Our findings suggest that BC, derived in western industrialised nations primarily from diesel engines and biomass burning, poses a significant burden to public health, particularly in European cities with high-traffic density.

Air pollution and cardiovascular and respiratory emergency visits in Central Arkansas: A time-series analysis

BACKGROUND Heart disease and stroke mortality and morbidity rates in Arkansas are among the highest in the U.S. While the effect of air pollution on cardiovascular health was identified in traffic-dominated metropolitan areas, there is a lack of studies for populations with variable exposure profiles, demographic and disease characteristics. OBJECTIVE Determine the short-term effects of air pollution on cardiovascular and respiratory morbidity in the stroke and heart failure belt. METHODS We investigated the associations of fine particles and ozone with respiratory and cardiovascular emergency room visits during the 2002-2012 period for adults in Central Arkansas using Poisson generalized models adjusted for temporal, seasonal and meteorological effects. We evaluated sensitivity of the associations to mutual pollutant adjustment and effect modification patterns by sex, age, race and season. RESULTS We found effects on cardiovascular and respiratory emergencies for PM2.5 (1.52% [95% (confidence interval) CI: -1.10%, 4.20%]; 1.45% [95%CI: -2.64%, 5.72%] per 10 μg/m3) and O3 (0.93% [95%CI: -0.87%, 2.76%]; 0.76 [95%CI: -1.92%, 3.52%] per 10 ppbv) during the cold period (October-March). The effects were stronger among whites, except for the respiratory effects of O3 that were higher among Blacks/African-Americans. Effect modification patterns by age and sex differed by association. Both pollutants were associated with increases in emergency room visits for hypertension, heart failure and asthma. Effects on cardiovascular and respiratory emergencies were observed during the cold period when particulate matter was dominated by secondary nitrate and wood burning. CONCLUSION Outdoor particulate pollution during winter had an effect on cardiovascular morbidity in central Arkansas, the region with high stroke and heart disease incidence rates.

Is daily exposure to ozone associated with respiratory morbidity and lung function in a representative sample of schoolchildren? Results from a panel study in Greece

Previous time series or panel studies of asthmatics have reported respiratory health effects following short-term exposure to ozone (O3). We followed 186 children aged 10 years old in Athens and Thessaloniki, Greece for 5 weeks during the academic year 2013–2014 and recorded daily their respiratory symptoms, absenteeism and peak expiratory flow (PEF). We applied mixed models controlling for various possible confounders to investigate the daily associations between O3 exposure — derived from weekly personal and fixed school site measurements calibrated using daily values of the fixed monitoring site nearest to the child’s school location — and PEF, presence of any symptom, cough and stuffy nose, as well as absenteeism. We tested the robustness of our findings to varying modeling assumptions and confounders and investigated effect modification patterns by medication use, time spent outdoors and prevalence of asthma. A 10 μg/m3 increase in O3 personal exposure was associated with increased odds of any symptom (odds ratio (OR): 1.19, 95% confidence interval (CI): 0.98, 1.44), largely attributed to the increase in the odds of stuffy nose (OR: 1.23, 95% CI: 1.00, 1.51). PEF and absenteeism were not related to O3 exposure. Our results were robust to several sensitivity analyses. Effects were modified by medication use as presence of symptoms but also decreases in PEF were mainly reported among non-users, while our effect estimates were not driven by the asthmatic subgroup of children. Our findings indicate that short-term O3 exposure may be associated with respiratory symptoms extending previously reported results for asthmatics to the general population.

Determinants of personal exposure to ozone in school children. Results from a panel study in Greece

Background: In the wider framework of the RESPOZE (ReSPiratory effects of OZone Exposure in Greek children) panel study, we investigated possible determinants of O3 exposure of school children, measured with personal passive samplers, in Athens and Thessaloniki, Greece. Methods: Personal exposure to O3 was measured for five weeks spread along the academic year 2013‐14, in 186 school children in Athens and Thessaloniki, Greece. At the same time, at‐school outdoor measurements were performed and ambient levels of 8‐h daily maximum O3 from fixed sites were collected. We also collected information on lifestyle and housing characteristics through an extended general questionnaire (GQ) and each participant completed daily time activity diaries (TADs) during the study period. Results: Mean outdoor concentrations were higher during the warmer months, in the suburbs of the cities and in Athens. Personal exposure concentrations were significantly lower compared to outdoor. Daily levels of at‐school outdoor and ambient levels of O3 from fixed sites were significant determinants of personal exposure to O3. For a 10 &mgr;g/m3 increase in at‐school outdoor O3 concentrations and PM10 measurements a 20.9% (95% CI: 13%, 28%) increase in personal exposure to O3 was found. For a half an hour more spent in transportation an average increase of 7% (95% CI: 0.3%, 14.6%) in personal exposure to O3 was observed. Among other possible determinants, time spent in transportation (TAD variable) and duration of open windows were the ones associated with personal O3 exposure levels. Conclusions: Our results support the use of outdoor and ambient measurements from fixed sites in epidemiological studies as a proxy of personal exposure to O3, but this has to be calibrated taking into account personal measurements and time‐activity patterns. HighlightsPossible determinants of personal ozone exposure of school children were investigated.Methods rely on personal passive samplers and simultaneously at‐school measurements.Epidemiological studies may use ambient measurements as a proxy for personal exposure.

OP XII – 1 Assessing the cumulative health effect following short term exposure to multiple pollutants: an evaluation of methodological approaches using simulations and real data

Background/aim Assessment of the cumulative effect of correlated exposures is an open methodological issue in environmental epidemiology. Previous studies applied regression models with interaction terms or dimension reduction methods. The joint effect of pollutants has been also evaluated using weighted exposure scores with weights based on the strength of the specific pollutant-health outcomes associations. Methods We compared three approaches addressing multipollutant exposures in epidemiological models: main effects models, the adaptive least absolute shrinkage and selection operator (LASSO) and a weighted exposure score. We assessed the performance of the methods by simulations under various scenarios for the pollutants’ correlations. We further applied the three methods to time series data from Athens, Greece for 2007–2012 to investigate the combined effect of short-term exposure to six regulated pollutants on all-cause and respiratory mortality. Results The weighted exposure score provided the least biassed cumulative estimate under all correlation scenarios for both mortality outcomes. The adaptive LASSO performed well in the case of low and medium correlation between exposures while models including all exposures linearly seriously biassed the estimate of interest. In the real data application, the cumulative effect estimate on overall mortality was similar between approaches ranging from 1.12% increase in main effects models to 0.73% in the score, while the cumulative effect on respiratory mortality resulted in variable estimates, that ranged from −0.61% increase for adaptive LASSO to 2.77% for the score approach, with overlapping confidence intervals. Conclusion The use of a weighted exposure score to address cumulative effects of correlated metrics may perform well under different exposure correlation structures and different variability in the health outcomes. Future work should assess the performance of methods under variable lag structures per pollutant or non-linear associations between pollutants and outcomes.

Assessing the cumulative health effect following short term exposure to multiple pollutants: An evaluation of methodological approaches using simulations and real data

Background Assessment of the cumulative effect of correlated exposures is an open methodological issue in environmental epidemiology. Most previous studies have applied regression models with interaction terms or dimension reduction methods. The combined effect of pollutants has been also evaluated through the use of exposure scores that incorporate weights based on the strength of the component‐specific associations with health outcomes. Methods We compared three approaches addressing multi‐pollutant exposures in epidemiological models: main effects models, the adaptive least absolute shrinkage and selection operator (LASSO) and a weighted exposure score. We assessed the performance of the methods by simulations under various scenarios for the pollutants’ correlations. We further applied these methods to time series data from Athens, Greece in 2007–12 to investigate the combined effect of short‐term exposure to six regulated pollutants on all‐cause and respiratory mortality. Results The exposure score provided the least biased estimate under all correlation scenarios for both mortality outcomes. The adaptive LASSO performed well in the case of low and medium correlation between exposures while the main effect model resulted in severe bias. In the real data application, the cumulative effect estimate was similar between approaches for all‐cause mortality ranging from 0.7% increase per interquartile range (IQR) (score) to 1.1% (main effects), while for respiratory mortality conclusions were contradictive and ranged from − 0.6% (adaptive LASSO) to 2.8% (score). Conclusions The use of a weighted exposure score to address cumulative effects of correlated metrics may perform well under different exposure correlation and variability in the health outcomes. HighlightsCorrelated exposures’ cumulative effect is a challenging methodological issue.Simulations indicated the use of exposure score as the least biased approach.The main effects approach presented the poorest performance.The adaptive LASSO performed well when correlation was low or moderate.