Polynomial Distributed Lag Models Research Articles

Differential associations of fine and coarse particulate air pollution with cause-specific pneumonia mortality: A nationwide, individual-level, case-crossover study

BackgroundThe connections between fine particulate matter (PM2.5) and coarse particulate matter (PM2.5-10) and daily mortality of viral pneumonia and bacterial pneumonia were unclear. ObjectivesTo distinguish the connections between PM2.5 and PM2.5-10 and daily mortality due to viral pneumonia and bacterial pneumonia. MethodsUsing a comprehensive national death registry encompassing all areas of mainland China, we conducted a case-crossover investigation from 2013 to 2019 at an individual level. Residential daily particle concentrations were evaluated using satellite-based models with a spatial resolution of 1 km. To analyze the data, we employed the conditional logistic regression model in conjunction with polynomial distributed lag models. ResultsWe included 221,507 pneumonia deaths in China. Every interquartile range (IQR) elevation in concentrations of PM2.5 (lag 0–2 d, 37.6 μg/m3) was associated with higher magnitude of mortality for viral pneumonia (3.03%) than bacterial pneumonia (2.14%), whereas the difference was not significant (p-value for difference = 0.38). An IQR increase in concentrations of PM2.5-10 (lag 0–2 d, 28.4 μg/m3) was also linked to higher magnitude of mortality from viral pneumonia (3.06%) compared to bacterial pneumonia (2.31%), whereas the difference was not significant (p-value for difference = 0.52). After controlling for gaseous pollutants, their effects were all stable; however, with mutual adjustment, the associations of PM2.5 remained, and those of PM2.5-10 were no longer statistically significant. Greater magnitude of associations was noted in individuals aged 75 years and above, as well as during the cold season. ConclusionThis nationwide study presents compelling evidence that both PM2.5 and PM2.5-10 exposures could increase pneumonia mortality of viral and bacterial causes, highlighting the more robust effects of PM2.5 and somewhat higher sensitivity of viral pneumonia.

Differentiating the effects of fine and coarse particulate air pollution on the onset of stable and unstable angina: a case-crossover study in 305 Chinese cities

Background and purpose: Associations between fine and coarse particulate matters (i.e., PM2.5 and PM2.5–10, respectively) and the onset of angina have rarely been investigated. We aimed to systematically explore the impacts of PM2.5 as well as PM2.5–10 on the onset of stable and unstable angina at the hourly timescale. Methods: We performed a time-stratified case-crossover study among 995,734 angina patients from 1,655 hospitals in 305 Chinese cities from January 2015 to December 2021. Concentrations of PM2.5 and PM2.5–10 were collected at the hourly timescale from nearby fixed-site monitoring stations. Hourly onset information of unstable and stable angina was obtained from the Chinese Cardiovascular Association Database-Chest Pain Center. We applied conditional logistic regressions combined with polynomial distributed lag models to explore the lagged exposure–response associations. Subgroup analyses were performed to explore potential effect modifiers including age, sex, season, and region. Results: Transient exposure to PM2.5 was significantly associated with elevated risk of unstable and stable angina onset. The associations occurred immediately in the concurrent hour of exposure, attenuated thereafter, and turned to null at approximately lag 12 h for unstable angina and 9 h for stable angina. Each interquartile range increase in the PM2.5 concentrations over 0 to 12 h was associated with 1.32% (95% confidence interval [95% CI]: 0.94%–1.70%) and 1.69% (95% CI: 0.99%–2.39%) increase in the onset risk of unstable and stable angina, respectively. The results remained similar after controlling for co-pollutants. Greater magnitudes of associations were found among females and during cold season. Null associations were observed between PM2.5–10 and any type of angina. Conclusion: Our study indicates that acute exposure to PM2.5, rather than PM2.5–10, was significantly associated with the onset of both unstable and stable angina, underscoring the need of continued efforts in controlling particulate matter air pollution.

Acute Impact of Fine Particulate Air Pollution on Cardiac Arrhythmias in a Population-Based Sample of Adolescents: The Penn State Child Cohort.

Background Fine particulate (fine particles with aerodynamic diameters ≤2.5 μm [PM2.5]) exposure has been associated with a risk of cardiac arrhythmias in adults. However, the association between PM2.5 exposure and cardiac arrhythmias in adolescents remains unclear. Methods and Results To investigate the association and time course between PM2.5 exposure with cardiac arrhythmias in adolescents, we analyzed the data collected from 322 adolescents who participated in the PSCC (Penn State Child Cohort) follow-up examination. We obtained individual-level 24-hour PM2.5 concentrations with a nephelometer. Concurrent with the PM2.5 measure, we obtained 24-hour ECG data using a Holter monitor, from which cardiac arrhythmias, including premature atrial contractions and premature ventricular contractions (PVCs), were identified. PM2.5 concentration and numbers of premature atrial contractions/PVCs were summarized into 30-minute-based segments. Polynomial distributed lag models within a framework of a negative binomial model were used to assess the effect of PM2.5 concentration on numbers of premature atrial contractions and PVCs. PM2.5 exposure was associated with an acute increase in number of PVCs. Specifically, a 10 μg/m3 increase in PM2.5 concentration was associated with a 2% (95% CI, 0.4%-3.3%) increase in PVC counts 0.5 to 1.0, 1.0 to 1.5, and 1.5 to 2.0 hours after the exposure. Cumulatively, a 10 μg/m3 increment in PM2.5 was associated with a 5% (95% CI, 1%-10%) increase in PVC counts within 2 hours after exposure. PM2.5 concentration was not associated with premature atrial contraction. Conclusions PM2.5 exposure was associated with an acute increased number of ventricular arrhythmias in a population-based sample of adolescents. The time course of the effect of PM2.5 on ventricular arrhythmia is within 2 hours after exposure.

Size-segregated particle number concentrations and outpatient-department visits for pediatric respiratory diseases in Shanghai, China

BackgroundFew studies have simultaneously explored which size of particles has the greatest impact on the risk for pediatric asthma, bronchitis and upper respiratory tract infections (URTIs). ObjectivesTo investigate the short-term association between size-segregated particle number concentrations (PNCs) and outpatient-department visits (ODVs) for major pediatric respiratory diseases. MethodsDaily counts of pediatric ODVs for asthma, bronchitis and URTIs were obtained from 66 hospitals in Shanghai, China, from 2016 to 2018. Pollutant effects were estimated using Poisson generalized additive models combined with polynomial distributed lag models. We also fitted co-pollutant cumulative effects models included six criteria air pollutants and conducted stratifying analyses by gender, age, season and geographic distances. ResultsWe identified a total of 430,103 patients with asthma, 1,547,013 patients with bronchitis, and 2,155,738 patients with URTIs from the hospitals. Effect estimates increased with decreasing particle size. Ultrafine particle (UFP) and PNCs of 0.10–0.40 µm particles (PNC0.10–0.40) were associated with increased ODVs for asthma, bronchitis and URTIs at cumulative lags up to 3d. Associations tended to appear stable after adjusting for criteria air pollutants. At the cumulative lag 0–2d, each interquartile range increase in UFP was associated with increased ODVs due to asthma (relative risk 1.21, 95% CI: 1.07, 1.38), bronchitis (1.20, 95% CI: 1.07, 1.34) and URTI (1.17, 95% CI: 1.06, 1.30), whereas the associations for PNC0.10–0.40 remained significant but attenuated in magnitude. ConclusionsUFP may be a leading contributor to the adverse respiratory effects of particulate air pollution and the effects increased with decreasing particle size.

Dynamics of macroeconomic factor effects on food assistance program participation in the United States.

Using polynomial distributed lag (PDL) models, the impacts of macroeconomic factors relating to economic, financial, and sociological stress and designed to be short-run predictors of U.S. economic performance are identified and assessed concerning participation in key food assistance programs (SNAP, WIC, and NSLP). The econometric analysis covers the period October 1999 to September 2020. The impact of COVID-19 on participation in these programs also is quantified. Based on the parameter estimates obtained from the econometric PDL models, ex-ante forecasts of participation in the SNAP, WIC, and NSLP subsequently are made and evaluated over the period October 2020 to August 2021. The empirical results show that different sets of macroeconomic drivers affect participation levels across the respective food assistance programs. No macroeconomic factor is common across SNAP, WIC, and NSLP participation. Changes in macroeconomic conditions which influence SNAP, WIC and NSLP participation are not just contemporaneous but also affect participation levels anywhere from 1 month to 12 months later. Importantly, this research allows not only the determination of the macroeconomic factors which affect program participation but also allows the determination of the ability of the respective models to forecast program participation. As such, the Food and Nutrition Service will be in better position to assess program needs as well as to forecast program participation levels to minimize errors in the budgetary process.

Hourly Air Pollutants and Acute Coronary Syndrome Onset in 1.29 Million Patients.

Short-term exposure to ambient air pollution has been linked with daily hospitalization and mortality from acute coronary syndrome (ACS); however, the associations of subdaily (hourly) levels of criteria air pollutants with the onset of ACS and its subtypes have rarely been evaluated. We conducted a time-stratified case-crossover study among 1 292 880 patients with ACS from 2239 hospitals in 318 Chinese cities between January 1, 2015, and September 30, 2020. Hourly concentrations of fine particulate matter (PM2.5), coarse particulate matter (PM2.5-10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3) were collected. Hourly onset data of ACS and its subtypes, including ST-segment-elevation myocardial infarction, non-ST-segment-elevation myocardial infarction, and unstable angina, were also obtained. Conditional logistic regressions combined with polynomial distributed lag models were applied. Acute exposures to PM2.5, NO2, SO2, and CO were each associated with the onset of ACS and its subtypes. These associations were strongest in the concurrent hour of exposure and were attenuated thereafter, with the weakest effects observed after 15 to 29 hours. There were no apparent thresholds in the concentration-response curves. An interquartile range increase in concentrations of PM2.5 (36.0 μg/m3), NO2 (29.0 µg/m3), SO2 (9.0 µg/m3), and CO (0.6 mg/m3) over the 0 to 24 hours before onset was significantly associated with 1.32%, 3.89%, 0.67%, and 1.55% higher risks of ACS onset, respectively. For a given pollutant, the associations were comparable in magnitude across different subtypes of ACS. NO2 showed the strongest associations with all 3 subtypes, followed by PM2.5, CO, and SO2. Greater magnitude of associations was observed among patients older than 65 years and in the cold season. Null associations of exposure to either PM2.5-10 or O3 with ACS onset were observed. The results suggest that transient exposure to the air pollutants PM2.5, NO2, SO2, or CO, but not PM2.5-10 or O3, may trigger the onset of ACS, even at concentrations below the World Health Organization air quality guidelines.

Hourly concentrations of fine and coarse particulate matter and dynamic pulmonary function measurements among 4992 adult asthmatic patients in 25 Chinese cities

The short-term associations of fine particulate matter (PM2.5) and coarse particulate matter (PM2.5-10) with pulmonary function were inconsistent and rarely evaluated by dynamic measurements. Our study aimed to investigate the associations of PM2.5 and PM2.5–10 with real-time pulmonary function. We conducted a longitudinal study based on dynamic pulmonary function measurements among adult asthmatic patients in 25 cities of 19 provincial regions of China from 2017 to 2020. Linear mixed-effects models combined with polynomial distributed lag models were used for statistical analysis. A total of 298,396 records among 4,992 asthmatic patients were evaluated. We found generally inverse associations of PM2.5 and PM2.5–10 with 16 pulmonary function indicators that were independent of gaseous pollutants. The associations occurred at lag 1 d, became the strongest at lag 4 d, and vanished a week later. PM2.5-10 had stronger associations than PM2.5, especially in southern China. Nationally, an interquartile increase in PM2.5-10 (28.0 μg/m3) was significantly associated with decreases in forced expiratory volume in 1 s (FEV1, 41.6 mL), the ratio of FEV1 in forced vital capacity (1.1%), peak expiratory flow (136.9 mL/s), and forced expiratory flow at 25–75% of forced vital capacity (54.3 mL/s). We observed stronger associations in patients of male, BMI ≥ 25 kg/m2, age ≥ 45 years old, and during warm seasons. In conclusion, this study provided robust evidence for impaired pulmonary function by short-term exposure to PM2.5 and PM2.5-10 in asthmatic patients using the largest dataset of dynamic monitoring. The associations can last for one week and PM2.5-10 may be more hazardous.

Abstract 027: Individual-level Fine Particulate Air Pollution Is Associated With Arrhythmia In Adolescents

Introduction: Fine particulate (PM 2.5 ) exposure has been related to higher propensity of arrhythmias in adults. However, the association between PM 2.5 exposure and arrhythmia in adolescents remains unclear. Hypothesis: PM 2.5 exposure is related to an acute increase in numbers of arrhythmic heartbeats in adolescents. Methods: We used data collected from 421 adolescents in the Penn State Child Cohort (PSCC) follow-up examination for this report. From each participant, we obtained 24-hour beat-to-beat ECG data using a 12-lead Holter ECG. From which, arrhythmias, including premature ventricular contraction (PVC) and premature atrial contraction (PAC), were identified. The number of PVCs and PACs every 30 minutes were analyzed with individual-level 30-minute average PM 2.5 concentrations obtained by using a personal minute-by-minute PM 2.5 monitor for 24 hours in parallel to the ECG. Thus, each participant contributed 48 30-minute segments of arrhythmia and PM 2.5 data. Polynomial distributed lag models within a framework of a negative binomial model were used to assess the segment-specific and cumulative effect of PM 2.5 concentration on numbers of PVC and PAC, adjusting for age, race, sex, BMI percentile, temperature, and humidity. Results: The mean (SD) age of PSCC was 16.9 (2.2) years, with 54% males, and 78% whites. The 30-minute mean (SD) of PM 2.5 concentration was 14.4 (45.4) μg/m 3 , while PVC and PAC counts were 0.2 (2.0) and 0.5 (4.0). As shown in the table, 10 μg/m 3 increases in PM 2.5 concentration 0.5-2.0 hours prior to the ECG measures (lags 1-3) each were associated with 2% increase in PVC counts (all p<0.05). Cumulatively, a 10 μg/m 3 increment in PM 2.5 was associated with a 5% (1% - 10%) increase in PVC counts within 2 hours after exposure. PM 2.5 was not related to PAC counts. Conclusion: Individual-level exposure to PM 2.5 is associated with an acute increased number of ventricular arrhythmia in population-based adolescents. The time course of the effect of PM 2.5 on ventricular arrhythmia is within 2 hours after exposure.

Ultrafine particulate air pollution and pediatric emergency-department visits for main respiratory diseases in Shanghai, China

BackgroundFew studies have explored the short-term effects of ultrafine particles (UFPs, particles < 0.1 μm) air pollution on the exacerbations of pediatric respiratory diseases. ObjectivesWe aimed to evaluate short-term association between UFP and emergency-department visits (EDVs) for main pediatric respiratory diseases. MethodsWe collected daily data on UFP and pediatric EDVs for main respiratory diseases [asthma, pneumonia, bronchitis and upper respiratory tract infections (URTI)] from 66 hospitals in Shanghai, China from 2016 to 2018. Generalized additive models combined with polynomial distributed lag models were applied to explore the associations between UFP level and pediatric EDVs for respiratory diseases. We fitted two-pollutant models with criteria air pollutants and performed stratified analyses by gender and age. ResultsUFP was associated with increased EDVs for all respiratory diseases in cumulative lags up to 2 d and 3 d. The greatest risk was found at cumulative lags (0–2 d) for all respiratory diseases. At cumulative lags (0–2 d), an interquartile range increase in concentrations of UFP (1800 particles/cm3) was associated with relative risks of EDVs due to asthma [1.35, 95% confidence interval (CI): 1.14–1.59], pneumonia (1.20, 95% CI: 1.04–1.38), bronchitis (1.17, 95% CI: 1.03–1.33) and URTI (1.14, 95% CI: 1.02–1.28). These associations were almost unchanged when controlling for criteria air pollutants, and there was no threshold below which the associations were not present. There were stronger associations in children aged 0–13 years. ConclusionsShort-term exposure to UFP may independently increase the risks of EDVs for asthma, pneumonia, bronchitis and URTI exacerbations among children.

Source-Specific Volatile Organic Compounds and Emergency Hospital Admissions for Cardiorespiratory Diseases.

Knowledge gaps remain regarding the cardiorespiratory impacts of ambient volatile organic compounds (VOCs) for the general population. This study identified contributing sources to ambient VOCs and estimated the short-term effects of VOC apportioned sources on daily emergency hospital admissions for cardiorespiratory diseases in Hong Kong from 2011 to 2014. We estimated VOC source contributions using fourteen organic chemicals by positive matrix factorization. Then, we examined the associations between the short-term exposure to VOC apportioned sources and emergency hospital admissions for cause-specific cardiorespiratory diseases using generalized additive models with polynomial distributed lag models while controlling for meteorological and co-pollutant confounders. We identified six VOC sources: gasoline emissions, liquefied petroleum gas (LPG) usage, aged VOCs, architectural paints, household products, and biogenic emissions. We found that increased emergency hospital admissions for chronic obstructive pulmonary disease were positively linked to ambient VOCs from gasoline emissions (excess risk (ER%): 2.1%; 95% CI: 0.9% to 3.4%), architectural paints (ER%: 1.5%; 95% CI: 0.2% to 2.9%), and household products (ER%: 1.5%; 95% CI: 0.2% to 2.8%), but negatively associated with biogenic VOCs (ER%: −6.6%; 95% CI: −10.4% to −2.5%). Increased congestive heart failure admissions were positively related to VOCs from architectural paints and household products in cold seasons. This study suggested that source-specific VOCs might trigger the exacerbation of cardiorespiratory diseases.

Fine particulate matter constituents and cause-specific mortality in China: A nationwide modelling study

BackgroundFine particulate matter (with aerodynamic diameter ≤2.5 µm, PM2.5) causes huge disease burden worldwide. However, evidence is still inadequate and inconsistent on the relationships between PM2.5 constituents and mortality, especially in low resource settings. ObjectivesTo evaluate the impact of PM2.5 constituents on cause-specific mortality in China. MethodsWe obtained daily mortality data for 161 communities in 2011–2013 from the Disease Surveillance Point system in China. Daily concentrations of major PM2.5 constituents, including organic carbon (OC), elemental carbon (EC), sulphate (SO42-), nitrate (NO3-) and ammonium (NH4+), were estimated by using the modified Community Multiscale Air Quality model. For each community, we applied quasi-Poisson regression and polynomial distributed lag models to estimate the effects of PM2.5 constituents on cause-specific mortality. Then, the pooled effect estimates were calculated by a random-effect meta-analysis based on the restricted maximum likelihood estimation. Stratification analyses were performed by region, gender, age group and education level to identify the vulnerable populations. ResultsEach interquartile range change of EC, OC, SO42-, NO3- and NH4+ at lag 0–3 day was associated with increments in non-accidental mortality of 0.45% (95%CI: 0.21, 0.69), 1.43% (0.97, 1.89), 0.71% (0.28, 1.15), 0.70% (0.10, 1.30) and 0.95% (0.39, 1.51), respectively. The associations were stronger for the deaths from cardiovascular disease and myocardial infarction, the elderly, illiterates, and people living in the South region. ConclusionsOur findings suggest positive associations between PM2.5 constituents and cause-specific mortality, particularly for myocardial infarction.

Modelling prices and the reputation of individual named wines

ABSTRACTThis article develops empirical models to assess the relation between the reputation of an individual named wine and its price. Unrestricted and polynomial distributed lag models are used to assess the impact of past expert quality ratings on the prices of Australian premium wines. Results point to the practical unimportance of current wine quality scores impacting prices and suggest that quality score lag effects up to six years may be important. The largest individual lagged impact of quality on price is estimated to occur at approximately two years, and prices are estimated to increase by more than 10% over six years for a one-point quality score increase. A procedure for identifying potential wine price bargains based on a comparison of price predictions from estimated wine reputation and current quality measures is illustrated. The implications of the findings for wine producers are also discussed.

Effects of air pollution on infant and children respiratory mortality in four large Latin-American cities

ObjectivesAir pollution is an important public health concern especially for children who are particularly susceptible. Latin America has a large children population, is highly urbanized and levels of pollution are substantially high, making the potential health impact of air pollution quite large. We evaluated the effect of air pollution on children respiratory mortality in four large urban centers: Mexico City, Santiago, Chile, and Sao Paulo and Rio de Janeiro in Brazil. MethodsGeneralized Additive Models in Poisson regression was used to fit daily time-series of mortality due to respiratory diseases in infants and children, and levels of PM10 and O3. Single lag and constrained polynomial distributed lag models were explored. Analyses were carried out per cause for each age group and each city. Fixed- and random-effects meta-analysis was conducted in order to combine the city-specific results in a single summary estimate. ResultsThese cities host nearly 43 million people and pollution levels were above the WHO guidelines. For PM10 the percentage increase in risk of death due to respiratory diseases in infants in a fixed effect model was 0.47% (0.09–0.85). For respiratory deaths in children 1–5 years old, the increase in risk was 0.58% (0.08–1.08) while a higher effect was observed for lower respiratory infections (LRI) in children 1–14 years old [1.38% (0.91–1.85)]. For O3, the only summarized estimate statistically significant was for LRI in infants. Analysis by season showed effects of O3 in the warm season for respiratory diseases in infants, while negative effects were observed for respiratory and LRI deaths in children. DiscussionWe provided comparable mortality impact estimates of air pollutants across these cities and age groups. This information is important because many public policies aimed at preventing the adverse effects of pollution on health consider children as the population group that deserves the highest protection.

Air pollution and its impacts on health in Vitoria, Espirito Santo, Brazil.

ABSTRACTOBJECTIVE To analyze the impact of air pollution on respiratory and cardiovascular morbidity of children and adults in the city of Vitoria, state of Espirito Santo.METHODS A study was carried out using time-series models via Poisson regression from hospitalization and pollutant data in Vitoria, ES, Southeastern Brazil, from 2001 to 2006. Fine particulate matter (PM10), sulfur dioxide (SO2), and ozone (O3) were tested as independent variables in simple and cumulative lags of up to five days. Temperature, humidity and variables indicating weekdays and city holidays were added as control variables in the models.RESULTS For each increment of 10 µg/m3 of the pollutants PM10, SO2, and O3, the percentage of relative risk (%RR) for hospitalizations due to total respiratory diseases increased 9.67 (95%CI 11.84-7.54), 6.98 (95%CI 9.98-4.17) and 1.93 (95%CI 2.95-0.93), respectively. We found %RR = 6.60 (95%CI 9.53-3.75), %RR = 5.19 (95%CI 9.01-1.5), and %RR = 3.68 (95%CI 5.07-2.31) for respiratory diseases in children under the age of five years for PM10, SO2, and O3, respectively. Cardiovascular diseases showed a significant relationship with O3, with %RR = 2.11 (95%CI 3.18-1.06).CONCLUSIONS Respiratory diseases presented a stronger and more consistent relationship with the pollutants researched in Vitoria. A better dose-response relationship was observed when using cumulative lags in polynomial distributed lag models.

Acute effects of urban air pollution on respiratory emergency hospital admissions in the Canary Islands

In the cities of Las Palmas (L/P) de Gran Canaria and Santa Cruz (S/C) de Tenerife, Canary Islands, particulate matter is highly influenced by mineral dust because their proximity to the Sahara desert (PM10–2.5 levels are higher than PM2.5). In this context, the short-term association between different PM fractions and gaseous pollutants with emergency hospital admissions for all respiratory, chronic obstructive pulmonary disease (COPD) and asthma was analyzed, evaluating the potential independent effect of PM10–2.5. A generalized additive model was fitted controlling for seasonal patterns and time varying confounders. Different lag structures, polynomial distributed lag models, and two-pollutant models were examined. Under Lag01, in S/C de Tenerife, a 10 μg/m3 increase in PM2.5 and PM10–2.5 was associated with a 5.1 % risk increase (95 % confidence interval [CI] 1.0 to 9.2) in all respiratory and with a 7.7 % increase (95 % CI 0.9 to 14.9) in COPD emergency admissions, respectively. In L/P de Gran Canaria, a positive association between PM10–2.5, PM2.5, and NO2 with the increased risk of asthma hospitalization was found: 11.2 % (95 % CI 0.5 to 22.9), 21.9 % (95 % CI 6.9 to 39.0), and a 17.4 % (95 % CI 6.6 to 29.4), respectively. The overall findings suggest that in these cities, (1) PM2.5, PM10–2.5, and NO2 are associated with the risk of emergency hospital admission for respiratory diseases; (2) there is no evidence of confounding for the associations observed; and (3) PM10–2.5 may have an impact on public health.

An Ecological Study Of The Relationship Between Mean Temperature And Mortality For Stroke In Elderly People

BACKGROUND: Several studies have shown the influence of climatic variables on hospital admissions and mortality from stroke. Since the organism of the elderly are more susceptible to changes in temperature, the aim of this study was to investigate the influence of temperature on stroke mortality in elderly people in São Paulo. METHODS: Daily mortality for stroke, meteorological variables and air pollution data were obtained for the period of January 2002 to December 2011. The percentage increase of mortality for total stroke, hemorrhagic, and ischemic were estimated with endpoint-specific generalized additive Poisson regression models. Effects of mean temperature, humidity, thermal amplitude, barometric pressure and air pollutants were assessed using specific third-degree polynomial distributed lag models for a time window of eight days. The models were controlled for humidity, atmospheric pressure, thermal amplitude and pollutants. RESULTS: In the ten years of study mortality from stroke was more than 55,000. To an increase in mean temperature of 1ºC we observed an estimated increase of mortality for stroke in elderly of 1.3% (CI 95%, 0.6-2.0) in total stroke mortality for each interquartile range increase for increase of 1ºC in mean temperature in the first two days. For women the increase was 7.8% (CI 95%, 3.1-12.7) and for men 1.1% (CI 95% 0.1-2.2). Ischemic stroke mortality also increased 14.1% (CI 95%, 8.1-20.4) for each 1ºC increase in mean temperature. Just for women the increase was 4.7% (CI 95%, 0.6-8.9) for each interquartile range. For hemorrhagic stroke no significative association was observed with mean temperature. CONCLUSION: The mean temperature affects total stroke mortality and ischemic stroke subgroup in elderly and, especially, in women. This reinforces the concept that the subgroups of stroke, ischemic and hemorrhagic, may present different pathophysiologic mechanisms and, hence, different risk factors.

Acute effects of particulate matter and black carbon from seasonal fires on peak expiratory flow of schoolchildren in the Brazilian Amazon.

BackgroundPanel studies have shown adverse effects of air pollution from biomass burning on children's health. This study estimated the effect of current levels of outdoor air pollution in the Amazonian dry season on peak expiratory flow (PEF).MethodsA panel study with 234 schoolchildren from 6 to 15 years old living in the municipality of Tangará da Serra, Brazil was conducted. PEF was measured daily in the dry season in 2008. Mixed-effects models and unified modelling repeated for every child were applied. Time trends, temperature, humidity, and subject characteristics were regarded. Inhalable particulate matter (PM10), fine particulate matter (PM2.5), and black carbon (BC) effects were evaluated based on 24-hour exposure lagged by 1 to 5 days and the averages of 2 or 3 days. Polynomial distributed lag models (PDLM) were also applied.ResultsThe analyses revealed reductions in PEF for PM10 and PM2.5 increases of 10 µg/m3 and 1 µg/m3 for BC. For PM10, the reductions varied from 0.15 (confidence interval (CI)95%: −0.29; −0.01) to 0.25 l/min (CI95%: −0.40; −0.10). For PM2.5, they ranged from 0.46 (CI95%: −0.86 to −0.06) to 0.54 l/min (CI95%:−0.95; −0.14). As for BC, the reduction was approximately 1.40 l/min. In relation to PDLM, adverse effects were noticed in models based on the exposure on the current day through the previous 3 days (PDLM 0–3) and on the current day through the previous 5 days (PDLM 0–5), specially for PM10. For all children, for PDLM 0–5 the global effect was important for PM10, with PEF reduction of 0.31 l/min (CI95%: −0.56; −0.05). Also, reductions in lags 3 and 4 were observed. These associations were stronger for children between 6 and 8 years old.ConclusionReductions in PEF were associated with air pollution, mainly for lagged exposures of 3 to 5 days and for younger children.

Association between Saharan dust days and emergency hospital admissions in Canary Islands

Background The proximity of the Canary Islands to the Northwestern Coast of Morocco (100km) and the regional atmospheric circulation result in an ideal scenario for the transport of African dust from Sahara and Sahel regions towards Canary Islandas. This phenomenon is known as "Saharan dust intrusions". These intrusions can last for one or more days (episodes), reaching occasionally daily average levels higher than 600 ?g/m3 of PM10 and 250 of PM2.5. Aims The aim of this study was to analyze in detail the short-term association between days with Saharan dust intrusions (Saharan dust days, SDD) and morbidity in the cities of Las Palmas de Gran Canaria (LPGC) and Santa Cruz de Tenerife (SCTF) Methods From 2001 to 2005 the association between SDD and daily emergency hospital admissions for respiratory and circulatory diseases was examined using Generalized Additive models adjusting for potential confounders. The effect of concurrent SDD and polynomial distributed lag models [PDLM]) were assessed. Two main types of Saharan dust intrusions over the islands (low and high altitude atmospheric intrusions) were also studied separately Results The number of episodes were 133 in LPGC and 142 in SCTF (561 and 591 SDD respectively). A SDD associated with a 22.6% increase (95% CI 10.4, 36.0) and 29.9% (6.6, 58.4) in risk of all respiratory and COPD admissions respectively in SCTF during the concurrent and the 5 consecutive days. Low altitude atmospheric dust days significantly associated with all respiratory 12.0% (2.7, 22.4) and COPD, 22.7% (4.7, 43.8) in SCTF and with asthma in LPGC: 31.3% (0.9, 70.8). Conclusions We found a short term impact of SDD on emergency hospital admissions for respiratory diseases in both cities that spread over several successive days and that are higher in low altitude atmospheric intrusions. Preventive actions and preparedness plans must be developed for public health protection from these natural events.

Impact of biomass burning and weather conditions on children’s health in a city of Western Amazon region

During the dry season in Brazilian Amazon, the population experiences severe smoke haze pollution in a region called “Arc of Devastation.” The increased pollution loading in the Amazonian atmosphere due to biomass burning emissions contributes significantly to global emissions of gases and particulate matter with important ecosystem and health impacts on local and regional populations. The aim of this study is to assess the lag structure among biomass burning air pollution exposure and environmental factors on children’s health in the municipality of Rio Branco, southwestern region of the Brazilian Amazon. In this paper, Poisson regressions via transfer function models were used and compared to polynomial distributed lag models to analyze the lagged and cumulative impacts of fine particulate matter and humidity exposure on daily demand of children’s hospital admissions due to respiratory causes from January 2004 to December 2009. Transfer function models presented better results. Increases of 10 μg/m3 in particles ≤ 2.5 μm/m3 aerodynamic diameter (PM2.5) exposure were associated with 5.6 % (95 % CI, 3.64−7.31) increase in hospital admissions due to respiratory diseases at lag 2. Effects of PM2.5 were acute and slight “harvesting” was found. Results demonstrate the adverse impact of biomass air pollution on health in the population, highlighting the need for public efforts to reduce this source of air pollution.

Time Course of Apparent Temperature Effects on Cardiovascular Mortality: A Comparative Study of Beijing, China and Brisbane, Australia

This comparative study aimed to clarify the different characteristics of time course of apparent temperature and their effect on cardiovascular mortality in Beijing, China, and Brisbane, Australia. The present study used polynomial distributed lag models to explore the lagged effects of apparent temperature on daily cardiovascular mortality up to 27 days in Beijing, China (2005–2009), and Brisbane, Australia (2004–2007). The results show a longer lagged effect on cold days and a shorter lagged effect on hot days. The cut-off points in Beijing and Brisbane were 22℃ and 27℃, respectively. In Beijing, a statistically significant association was observed for lags of 0–3 days and lags of 3–18 days on hot and cold days, respectively. In Brisbane, a significant association was found for lags of 3–4 days and lags of 10–21 days on hot and cold days, respectively. The lagged effects extended longer for cold apparent temperature but were immediate for hot apparent temperature. Though the cut-off point in Brisbane was higher than in Beijing, the population in Beijing was more resistant to high temperature above the cut-off point than the population in Brisbane.