Short-term Effects Of Air Pollution Research Articles

Using spatio-temporal land use regression models to address spatial variation in air pollution concentrations in time series studies

Time series studies are used to assess the effects of short-term exposures to PM10 and NO2 on mortality using an integrated pollutant series taken to characterize exposure over a large area. We propose using spatio-temporal land use regression (LUR) models by smaller geographical sectors within an area of interest to account for spatial variability in these studies. Based on model-estimated time series, we conducted a case-crossover analysis for each sub-sector within two larger areas of interest (Athens and Thessaloniki, Greece) separately to investigate heterogeneity and provide combined results if appropriate. As sensitivity analysis, we compared the case-crossover method to classical time series analysis and also to using fixed site measurements only. For PM10 exposures in Athens, we found consistent adverse effects which were larger when using spatio-temporal LUR modeled concentrations (total mortality RR 2.55 and 95% CI − 0.30 to 5.39) compared to measurements (RR 0.36 and 95% CI − 0.21 to 0.93). For NO2, we found a similar magnitude in the effects, when using measurements from fixed sites (RR 0.81 and 95% CI 0.39 to 1.22) and modeled levels (RR 0.71 and 95% CI 0.14 to 1.28). Analysis by geographical sector did not add information over a unified analysis for the whole area. The effect estimates using classical Poisson regression time series yielded consistently smaller size effects compared to the case-crossover method. Our analysis demonstrates the potential of using spatio-temporal models in time series analysis for short-term air pollution effects to account for spatial variability in addition to the temporal.

Association between air pollution and cardiovascular mortality in Hefei, China: A time-series analysis

In recent years, air pollution has become an alarming problem in China. However, evidence on the effects of air pollution on cardiovascular mortality is still not conclusive to date. This research aimed to assess the short-term effects of air pollution on cardiovascular morbidity in Hefei, China. Data of air pollution, cardiovascular mortality, and meteorological characteristics in Hefei between 2010 and 2015 were collected. Time-series analysis in generalized additive model was applied to evaluate the association between air pollution and daily cardiovascular mortality. During the study period, the annual average concentration of PM10, SO2, and NO2 was 105.91, 20.58, and 30.93 μg/m3, respectively. 21,816 people (including 11,876 man, and 14,494 people over 75 years of age) died of cardiovascular diseases. In single pollutant model, the effects of multi-day exposure were greater than single-day exposure of the air pollution. For every increase of 10 μg/m3 in SO2, NO2, and PM10 levels, CVD mortality increased by 5.26% (95%CI: 3.31%–7.23%), 2.71% (95%CI: 1.23%–4.22%), and 0.68% (95%CI: 0.33%–1.04%) at a lag03, respectively. The multi-pollutant models showed that PM10 and SO2 remained associated with CVD mortality, although the effect estimates attenuated. However, the effect of NO2 on CVD mortality decreased to statistically insignificant. Subgroup analyses further showed that women were more vulnerable than man upon air pollution exposure. These findings showed that air pollution could significantly increase the CVD mortality.

Air pollution and hospital visits for acute upper and lower respiratory infections among children in Ningbo, China: A time-series analysis.

Acute upper and lower respiratory infections are main causes of mortality and morbidity in children. Air pollution has been recognized as an important contributor to development and exacerbation of respiratory infections. However, few studies are available in China. In this study, we investigated the short-term effect of air pollution on hospital visits for acute upper and lower respiratory infections among children under 15years in Ningbo, China. Poisson generalized models were used to estimate the associations between air pollution and hospital visits for acute upper and lower respiratory infections adjusted for temporal, seasonal, and meteorological effects. We found that four pollutants (PM2.5, PM10, NO2, and SO2) were significantly associated with hospital visits for acute upper and lower respiratory infections. The effect estimates for acute upper respiratory infections tended to be higher (PM2.5 ER=3.46, 95% CI 2.18, 4.76; PM10 ER=2.81, 95% CI 1.93, 3.69; NO2 ER=11.27, 95% CI 8.70, 13.89; SO2 ER=15.17, 95% CI 11.29, 19.19). Significant associations for gaseous pollutants (NO2 and SO2) were observed after adjustment for particular matter. Stronger associations were observed among older children and in the cold period. Our study suggested that short-term exposure to outdoor air pollution was associated with hospital visits for acute upper and lower respiratory infections in Ningbo.

Air Pollution and Hospitalization for Acute Myocardial Infarction in China

There is growing interest in the association between ambient air pollution and acute myocardial infarction (AMI). The objective of this study was to explore the association in 14 Chinese cities using a time-stratified case-crossover design. We identified 80,787 hospital admissions for AMI between January 1, 2014 and December 31, 2015 from electronic hospitalization summary reports. Conditional logistic regression was used to estimate the percent changes with 95% confidence intervals (CIs) in AMI admissions in relation to an interquartile range increase in ambient air pollutant concentrations. All analyzed air pollutants, with the exception of ozone, were positively associated with daily AMI admissions on lag2 and lag3 days. An interquartile range increase in particulate matter <10 µm in aerodynamic diameter, sulfur dioxide, nitrogen dioxide, and carbon monoxide concentrations on lag2 day was significantly associated with a 0.8% (95% CI 0.1%, 1.6%), 2.0% (95% CI 1.2%, 2.9%), 2.2% (95% CI 1.4%, 3.1%), and 1.1% (95% CI 0.4%, 1.8%) increase in AMI admissions, respectively. We also observed a significant association in relation to ozone on lag4 day (percent change: 1.3%; 95% CI 0.2%, 2.4%). Subgroup analyses indicated no effect modification of risk by age (≥65 years and <65 years) or gender. In conclusion, this is the first multicity study in China, or even in other developing countries, to report the short-term effects of air pollution on AMI morbidity. Our findings contribute to the limited scientific data on the effects of ambient air pollution on AMI in developing countries.

Short-Term Associations between Air Pollution Concentrations and Respiratory Health—Comparing Primary Health Care Visits, Hospital Admissions, and Emergency Department Visits in a Multi-Municipality Study

Acute effects of air pollution on respiratory health have traditionally been investigated with data on inpatient admissions, emergency room visits, and mortality. In this study, we aim to describe the total acute effects of air pollution on health care use for respiratory symptoms (ICD10-J00-J99). This will be done by investigating primary health care (PHC) visits, inpatient admissions, and emergency room visits together in five municipalities in southern Sweden, using a case-crossover design. Between 2005 and 2010, there were 81,019 visits to primary health care, 38,217 emergency room visits, and 25,271 inpatient admissions for respiratory symptoms in the study area. There was a 1.85% increase (95% CI: 0.52 to 3.20) in the number of primary health care visits associated with a 10 µg/m3 increase in nitrogen dioxide (NO2) levels in Malmö, but not in the other municipalities. Air pollution levels were generally not associated with emergency room visits or inpatient admissions, with one exception (in Helsingborg there was a 2.52% increase in emergency room visits for respiratory symptoms associated with a 10 µg/m3 increase in PM10). In conclusion, the results give weak support for short-term effects of air pollution on health care use associated with respiratory health symptoms in the study area.

Association between air pollution and ventricular arrhythmias in high-risk patients (ARIA study): a multicentre longitudinal study

Although the effects of air pollution on mortality have been clearly shown in many epidemiological and observational studies, the pro-arrhythmic effects remain unknown. We aimed to assess the short-term effects of air pollution on ventricular arrhythmias in a population of high-risk patients with implantable cardioverter-defibrillators (ICDs) or cardiac resynchronisation therapy defibrillators (ICD-CRT). In this prospective multicentre study, we assessed 281 patients (median age 71 years) across nine centres in the Veneto region of Italy. Episodes of ventricular tachycardia and ventricular fibrillation that were recorded by the diagnostic device were considered in this analysis. Concentrations of particulate matter of less than 10 μm (PM10) and less than 2·5 μm (PM2·5) in aerodynamic diameter, carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone were obtained daily from monitoring stations, and the 24 h median value was considered. Each patient was associated with exposure data from the monitoring station that was closest to their residence. Patients were followed up for 1 year and then scheduled to have a closing visit, within 1 more year. This study is registered with ClinicalTrials.gov, number NCT01723761. Participants were enrolled from April 1, 2011, to Sept 30, 2012, and follow-ups (completed on April 5, 2014) ranged from 637 to 1177 days (median 652 days). The incidence of episodes of ventricular tachycardia and ventricular fibrillation correlated significantly with PM2·5 (p<0·0001) but not PM10. An analysis of ventricular fibrillation episodes alone showed a significant increase in risk of higher PM2·5 (p=0·002) and PM10 values (p=0·0057). None of the gaseous pollutants were significantly linked to the occurrence of ventricular tachycardia or ventricular fibrillation. In a subgroup analysis of patients with or without a previous myocardial infarction, only the first showed a significant association between particulate matter and episodes of ventricular tachycardia or ventricular fibrillation. Particulate matter has acute pro-arrhythmic effects in a population of high-risk patients, which increase on exposure to fine particles and in patients who have experienced a previous myocardial infarction. The time sequence of the arrhythmic events suggests there is an underlying neurally mediated mechanism. From a clinical point of view, the results of our study should encourage physicians to also consider environmental risk when addressing the prevention of arrhythmic events, particularly in patients with coronary heart disease, advising them to avoid exposure to high levels of fine particulate matter. There was no funding source for this study.

Short-term effects of air pollution on daily hospital admissions for cardiovascular diseases in western China

Controlling the confounding factors on cardiovascular diseases, such as long-time trend, calendar effect, and meteorological factors, a generalized additive model (GAM) was used to investigate the short-term effects of air pollutants (PM10, SO2, and NO2) on daily cardiovascular admissions from March 1st to May 31st during 2007 to 2011 in Lanzhou, a heavily polluted city in western China. The influences of air pollutants were examined with different lag structures, and the potential effect modification by dust storm in spring was also investigated. Significant associations were found between air pollutants and hospital admissions for cardiovascular diseases both on dust event days and non-dust event days in spring. Air pollutants had lag effects on different age and gender groups. Relative risks (RRs) and their 95% confidence intervals (CIs) associated with a 10μg/m3 increase were 1.14 (1.04~1.26) on lag1 for PM10, 1.31 (1.21~1.51) on lag01 for SO2, and 1.96 (1.49~2.57) on lag02 for NO2 on dust days. Stronger effects of air pollutants were observed for females and the elderly (≥60years). Our analysis concluded that the effects of air pollutants on cardiovascular admissions on dust days were significantly stronger than non-dust days. The current study strengthens the evidence of effects of air pollution on health and dust-exacerbated cardiovascular admissions in Lanzhou.

The short-term effects of air pollutants on respiratory disease mortality in Wuhan, China: comparison of time-series and case-crossover analyses

Few studies have compared different methods when exploring the short-term effects of air pollutants on respiratory disease mortality in Wuhan, China. This study assesses the association between air pollutants and respiratory disease mortality with both time-series and time-stratified–case-crossover designs. The generalized additive model (GAM) and the conditional logistic regression model were used to assess the short-term effects of air pollutants on respiratory disease mortality. Stratified analyses were performed by age, sex, and diseases. A 10 μg/m3 increment in SO2 level was associated with an increase in relative risk for all respiratory disease mortality of 2.4% and 1.9% in the case-crossover and time-series analyses in single pollutant models, respectively. Strong evidence of an association between NO2 and daily respiratory disease mortality among men or people older than 65 years was found in the case-crossover study. There was a positive association between air pollutants and respiratory disease mortality in Wuhan, China. Both time-series and case-crossover analyses consistently reveal the association between three air pollutants and respiratory disease mortality. The estimates of association between air pollution and respiratory disease mortality from the case–crossover analysis displayed greater variation than that from the time-series analysis.

Short-term effects of air pollution on hospitalization for acute myocardial infarction: age effect on lag pattern

The aim of the present study is to analyse the age effect on the lag patterns of relative risk of hospitalization for acute myocardial infarction and NO2, PM10 and O3. Daily hospitalizations for AMI during the period 2008–2011 were extracted from administrative data. Analyses were performed using the quasi-Poisson regression model adjusted for seasonality, long-term trend, day of the week and temperature. We observed very different patterns depending on age. For NO2 and PM10, the younger group (25–54 years) shows a more delayed effect in comparison with the two older age groups (55–64 and ≥ 65 years). Overall, the associations between NO2 and AMI are higher compared to PM10. There are no associations between O3 and AMI. This study indicates that age plays a major role in the lag pattern. Younger people have delayed effects, but they are nevertheless sensitive to air pollution.

Seasonal analysis of the short-term effects of air pollution on daily mortality in Northeast Asia

The constituents and concentrations of pollutants, individual exposures, and biologic responses to air pollution may vary by season and meteorological conditions. However, evidence regarding seasonality of the acute effects of air pollution on mortality is limited and inconsistent. Herein, we examined seasonal patterns in the short-term associations of particulate matter (PM) smaller than 10μm (PM10) with daily mortality in 29 cities of three northeast Asian countries. Stratified time-series models were used to determine whether season altered the effect of PM10 on mortality. This effect was first quantified within each season and at each location using a time-series model, after which city-specific estimates were pooled using a hierarchical Bayesian model. In all data sets, 3,675,348 non-accidental deaths were registered from 1993 to 2009. In Japan, a 10μg/m3 increase in PM10 was significantly associated with increases in non-accidental mortality of 0.44% (95% confidence interval [CI]: 0.03%, 0.8%) in spring and 0.42% (0.02%, 0.82%) in fall. In South Korea, a 10μg/m3 increase in PM10 was significantly associated with increases in non-accidental mortality of 0.51% (0.01%, 1.01%) in summer and 0.45% (0.03%, 0.87%) in fall, in cardiovascular disease mortality of 0.96% (0.29%, 1.63%) in fall, and in respiratory disease mortality of 1.57% (0.40%, 2.75%) in fall. In China, a 10μg/m3 increase in PM10 was associated with increases in non-accidental mortality of 0.33% (0.01%, 0.66%) in summer and 0.41% (0.09%, 0.73%) in winter, in cardiovascular disease mortality of 0.41% (0.08%, 0.74%) in spring and 0.33% (0.02%, 0.64%) in winter, and in respiratory diseases mortality of 0.78% (0.27%, 1.30%) in winter. Our analyses suggest that the acute effect of particulate air pollution could vary seasonally and geographically.

The effects of air pollution on asthma hospital admissions in Adelaide, South Australia, 2003-2013: time-series and case-crossover analyses.

Air pollution can have adverse health effects on asthma sufferers, but the effects vary with geographic, environmental and population characteristics. There has been no long time-series study in Australia to quantify the effects of environmental factors including pollen on asthma hospitalizations. This study aimed to assess the seasonal impact of air pollutants and aeroallergens on the risk of asthma hospital admissions for adults and children in Adelaide, South Australia. Data on hospital admissions, meteorological conditions, air quality and pollen counts for the period 2003-2013 were sourced. Time-series analysis and case-crossover analysis were used to assess the short-term effects of air pollution on asthma hospitalizations. For the time-series analysis, generalized log-linear quasi-Poisson and negative binomial regressions were used to assess the relationships, controlling for seasonality and long-term trends using flexible spline functions. For the case-crossover analysis, conditional logistic regression was used to compute the effect estimates with time-stratified referent selection strategies. A total of 36,024 asthma admissions were considered. Findings indicated that the largest effects on asthma admissions related to PM2.5 , NO2 , PM10 and pollen were found in the cool season for children (0-17 years), with the 5-day cumulative effects of 30.2% (95% CI: 13.4-49.6%), 12.5% (95% CI: 6.6-18.7%), 8.3% (95% CI: 2.5-14.4%) and 4.2% (95% CI: 2.2-6.1%) increases in risk of asthma hospital admissions per 10 unit increments, respectively. The largest effect for ozone was found in the warm season for children with the 5-day cumulative effect of an 11.7% (95% CI: 5.8-17.9%) increase in risk of asthma hospital admissions per 10 ppb increment in ozone level. Findings suggest that children are more vulnerable and the associations between exposure to air pollutants and asthma hospitalizations tended to be stronger in the cool season compared to the warm season, with the exception of ozone. This study has important public health implications and provides valuable evidence for the development of policies for asthma management.

Estimated short-term effects of air pollutants on daily respiratory emergency visits in three Swedish cities

The aim of the study was to estimate the short-term effects of different air pollutants on daily emergency visits (visits at an emergency room and acute admissions) for respiratory diagnoses in thr...

Time-varying short-term effects of air pollution in Rome from 1998-2014

Introduction: The association between air pollution and mortality has been widely investigated in epidemiological studies. However, little is known about its temporal evolution over long periods of time. Our aim is to evaluate the temporal relationship between air pollution and mortality in Rome from 1998-2014. Methods: We considered 359,447 natural deaths among people aged 35 years and older in Rome, Italy, between 1998-2014. We evaluated daily concentrations of particulate matter (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO) as exposures. We used a time-series analysis adjusted for time trends and meteorology. We estimated associations over the whole period and by individual years by fitting interaction terms between each pollutant and year. Results: Annual daily mean concentrations of all pollutants decreased substantially over the study period, with % decreases ranging from 90 for SO2 to 28 for NO2. Overall, all pollutants were significantly associated with natural deaths. Mortality increased by 1.27% (95%CI=0.90-1.64) and 0.19% (0.13-0.26) for increments of 10 ug/m3 and 1 mg/m3 of lag 0-1 PM10 and CO, respectively. Mortality increased by 3.03% (2.44-3.63) and 2.36% (1.61-3.11) for 10 ug/m3 and 1 ug/m3 variations in lag 0-5 NO2 and SO2, respectively. Annual estimates of pollutants display slightly no decreasing effects over the whole period but large year-to-year variability. When expressed per yearly interquartile ranges, effect estimates showed a clear decreasing trend for SO2 and CO only. Conclusions: Air pollution in Rome has substantially decreased over the last two decades. This has not resulted in changes in its effect on mortality, though a reduction of its impact has been detected for SO2 and CO as a consequence of reduction in concentrations. There is ongoing research to investigate how the main policy measures undertaken to reduce anthropogenic emissions over time might have influenced the relative composition of the pollution mixture.

Systematic review protocol for short-term effects of air pollution: how to address risk of bias from exposure assessment?

Systematic review protocol for short-term effects of air pollution: how to address risk of bias from exposure assessment?

Spatio-temporal variation of effects of short-term exposure to air pollutants on mortality in Seven Major Cities, Korea, 1998-2013

Introduction: heterogeneity in effect measure of short-term exposure to air pollution has been one of challenging issues in environmental epidemiology. In this preliminary study, we aim to investigate systematic variation of this effect measures in sixteen years and seven different cities, Korea. Methods: ordinary time-series analysis was conducted for association between PM10, NO2, SO2, O3, CO and mortality in Seoul, Busan, Daegu, Incheon, Gwangju, Daejeon, Ulsan. Temperature, relative humidity, unobserved long-term trend and variation in population size was adjusted. To see systematic variation, for each city, dataset was split to a series of eight years long windows and a regression was serially conducted. Variation of relative risks per unit increment of air pollutants was recorded for each windows and city. Results: we found systematic variation rather than random in spatio-temporality of relative risks. In Incheon, all of relative risks for five air pollutants decreased over time. On the contrary, in Busan, a trend was opposite except for non-trend O3. In Seoul, relative risks for gaseous pollutants decreased over time while that for PM increased. For Daegu, Gwangju, Ulsan, relative risks for several pollutants increased over time while those for the others was stationary. For Daejeon, no trend was found. Conclusion: this preliminary study shows possibility of systematic variation of relative risks for short-term effects of air pollutants on mortality. Possible reasons may be changes in population dynamics such as aging population, potential interaction with meteorological factors, harvesting, measurement errors, and essence of PM (e.g. portion of harmful particles). A main research would shed light on delineation of that systematic variation.

Long-Term Exposure to Traffic-Related Air Pollution and Risk of Incident Atrial Fibrillation: A Cohort Study.

Background:Atrial fibrillation is the most common sustained arrhythmia and is associated with cardiovascular morbidity and mortality. The few studies conducted on short-term effects of air pollution on episodes of atrial fibrillation indicate a positive association, though not consistently.Objectives:The aim of this study was to evaluate the long-term impact of traffic-related air pollution on incidence of atrial fibrillation in the general population.Methods:In the Danish Diet, Cancer, and Health cohort of 57,053 people 50–64 years old at enrollment in 1993–1997, we identified 2,700 cases of first-ever hospital admission for atrial fibrillation from enrollment to end of follow-up in 2011. For all cohort members, exposure to traffic-related air pollution assessed as nitrogen dioxide (NO2) and nitrogen oxides (NOx) was estimated at all present and past residential addresses from 1984 to 2011 using a validated dispersion model. We used Cox proportional hazard model to estimate associations between long-term residential exposure to NO2 and NOx and risk of atrial fibrillation, after adjusting for lifestyle and socioeconomic position.Results:A 10 μg/m3 higher 10-year time-weighted mean exposure to NO2 preceding diagnosis was associated with an 8% higher risk of atrial fibrillation [incidence rate ratio: 1.08; 95% confidence interval (CI): 1.01, 1.14] in adjusted analysis. Though weaker, similar results were obtained for long-term residential exposure to NOx. We found no clear tendencies regarding effect modification of the association between NO2 and atrial fibrillation by sex, smoking, hypertension or myocardial infarction.Conclusion:We found long-term residential traffic-related air pollution to be associated with higher risk of atrial fibrillation. Accordingly, the present findings lend further support to the demand for abatement of air pollution.Citation:Monrad M, Sajadieh A, Christensen JS, Ketzel M, Raaschou-Nielsen O, Tjønneland A, Overvad K, Loft S, Sørensen M. 2017. Long-term exposure to traffic-related air pollution and risk of incident atrial fibrillation: a cohort study. Environ Health Perspect 125:422–427; http://dx.doi.org/10.1289/EHP392

Short-term effects of air pollution, markers of endothelial activation, and coagulation to predict major adverse cardiovascular events in patients with acute coronary syndrome: insights from AIRACOS study

The aim of this study was to determine whether markers of inflammation and coagulation are associated with short-term particulate matter exposure and predict major adverse cardiovascular events at 360 d in patients with acute coronary syndrome (ACS). We included 307 consecutive patients, and assessed the average concentrations of data on atmospheric pollution in ambient air and meteorological variables from 1 d up to 7 d prior to admission. In patients with ACS, the markers of endothelial activation and coagulation, but not black carbon exposure, are associated with major adverse cardiovascular events at one-year follow-up.

Air pollution and risk of respiratory and cardiovascular hospitalizations in the most populous city in Vietnam

Air pollution has become an alarming issue in Vietnam recently; however, there was only one study so far on the effects of ambient air pollution on population health. Our study aimed to investigate the short-term effects of air pollutants including PM10, NO2, SO2, and O3 on respiratory and cardiovascular hospitalizations in Ho Chi Minh City (HCMC), the largest city in Vietnam. Data on hospitalization from the two largest hospitals in HCMC and daily records of PM10, NO2, SO2, O3 and meteorological data were collected from February 2004 to December 2007. A time-series regression analysis with distributed lag model was applied for data analysis. Changes in levels of NO2 and PM10 were strongly associated with hospital admissions for both respiratory and cardiovascular diseases (CVD); whereas levels of SO2 were only moderately associated with respiratory and CVD hospital admissions and O3 concentration was not associated with any of them. For a 10μg/m3 increase of each air pollutant, the risk of respiratory admissions increased from 0.7% to 8% while the risk of CVD admissions increased from 0.5% to 4%. Females were found to be more sensitive than males to exposure to air pollutants in regard to respiratory diseases. In regard to CVD, females (RR, 1.04, 95% CI, 1.01–1.07) had a slightly higher risk of admissions than males (RR, 1.03, 95% CI, 1–1.06) to exposure to NO2. In contrast, males (RR, 1.007, 95%CI, 1–1.01) had a higher risk of admission than females (RR, 1.004, 95%CI, 1.001–1.007) to exposure to PM10. People in the age group of 5–65year-olds had a slightly higher risk of admissions caused by air pollutants than the elderly (65+years old) except for a significant effect of PM10 on the risk of cardiovascular admissions was found for the elderly only.

Long-Term Residential Ambient Air Pollution and Rheumatoid Arthritis: A Systematic Review

Background: There has been increasing interest regarding the effects of air pollution on the risk of rheumatoid arthritis. Unfortunately, epidemiologic research on air pollution effects remains scant and offers conflicting results. Objectives: This study aimed to systematically review the epidemiologic literature on RA morbidity due to long-term residential air pollution. Materials and Methods: The authors independently carried out searches in MEDLINE and EMBASE through June 2015 (1974 - 2015). The searches were limited to English, Spanish and Russian. To complement the search strategy, authors and experts in the field were contacted, and hand-searches were carried out for articles included in reference lists. Peer-reviewed epidemiologic studies were eligible only if they explored the risk for RA in adults associated with air pollution exposure. Studies were omitted if they relied on self-report alone, experimental studies, short-term effects of air pollution, juvenile arthritis, or other autoimmune rheumatic diseases. Two authors independently extracted information about study characteristics. The study’s quality was assessed with the Newcastle-Ottawa scale. Results: Four relevant papers were included in a qualitative synthesis. Two studies showed significantly higher risks for RA in people living within 50 m of a heavy traffic road. No firm conclusions could be made for particulate matter. In one study, NO2 was associated with seronegative RA among smokers. The risk for SO2 was significant in one study. In the only relevant study, O3 was linked to RA. Conclusions: Proximity to road traffic might be a risk factor for RA as there are suspected effects associated with NO2 and SO2. Overall, the available evidence is too preliminary and scarce to draw firm conclusions. However, the results indicate the feasibility of further studies elucidating on the relationship between air pollution and RA.

Abstract TP167: Short-Term Exposures to Ambient Air Pollution and Risk of Recurrent Ischemic Stroke

Background: Recurrent strokes are associated with poor outcomes and mortality. Short-term ambient air pollution may be an important environmental risk factor for stroke recurrence. Although associations between air pollution and stroke risk have been observed, the evidence for short-term effects of air pollution on risk of stroke recurrence is in its infancy. We investigated the association between short-term changes in ambient pollution (particulate matter &lt;2.5μm (PM 2.5 ) and ozone (O 3 )) and the risk of recurrent ischemic stroke among individuals living in a bi-ethnic community. Methods: We identified recurrent ischemic stroke cases from the population-based Brain Attack Surveillance in Corpus Christi (BASIC) Project, an ongoing population-based stroke surveillance study in Nueces County, Texas, between 2000 and 2012. Associations between lags of 0 to 3 days PM 2.5 and O 3 levels and odds of ischemic stroke were assessed using a time-stratified case-crossover design. Conditional logistic regression models were used to calculate odds ratios (ORs) for a 10 unit change in exposure. Results: There were 317 recurrent ischemic strokes with mean age of 72 years (SD=12). Median levels of PM 2.5 and O 3 over the study period were 7.7μg/m 3 (IQR: 5.6-10.7μg/m 3 ) and 35.2ppb (IQR: 25.0-46.1ppb), respectively. No associations were observed across the different lagged exposures (0 to 3 days) after adjusting for ambient temperature and relative humidity (Figure). Co-adjustment of both pollutants results did not change the results. Conclusion: No association between PM 2.5 and O 3 and risk of recurrences was observed. Research on the influence of air pollutants on risk of recurrence is still in its infancy, and more research is needed to understand the relation.