Short-term effects of fine particulate air pollution on hospital admissions for hypertension: A time-stratified case-crossover study in Taipei

This study was undertaken to determine whether there was a correlation between fine particle (PM_2.5) levels and hospital admissions for hypertension in Taipei, Taiwan. Hospital admissions for hypertension and ambient air pollution data for Taipei were obtained for the period from 2009 to 2013. The relative risk of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single pollutant model (without adjustment for other pollutants), the risk of hospital admissions for hypertension was estimated to increase by 12% on warm days (>23°C) and 2% on cool days (<23°C), respectively. There was no indication of an association between levels of PM_2.5 and risk of hospital admissions for hypertension. In two-pollutant model, PM_2.5 remained nonsignificant after inclusion of any of the other air pollutants (SO₂, NO₂, CO, or O₃) both on warm and cool days, but a numerically greater response was seen on warm days. Data thus indicate that in Taipei, hospital admissions for hypertension occur as a consequence of factors not related to ambient air exposure.     

Association between fine particulate air pollution and hospital admissions for chest pain in a subtropical city: Taipei,Taiwan

This study determined the association between fine particles (PM_2.5) levels and hospital admissions for chest pain (CP) in Taipei, Taiwan. Hospital admissions for CP and ambient air pollution data for Taipei were obtained for the period 2009–2013. The relative risk of hospital admissions was estimated using a case-crossover approach, after controlling for weather variables, day of the week, seasonality, and long-term time trends. For single-pollutant models (without adjustment for other pollutants), increased frequency of CP admissions was significantly associated with PM_2.5 levels on warm days (>23°C), with an interquartile range rise correlated with a 15% (95% confidence interval = 11–31%) elevation in number of CP admissions. In two-pollutant models, PM_2.5 remained significant after inclusion of each of the other four pollutants: sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃) on warm days. Generally, no marked associations were observed between PM_2.5 levels and risk of CP admissions on cool days in both single- and two-pollutant models. This study provides evidence that higher PM_2.5 concentrations enhance the risk of hospital admissions for CP on warm days.     

Effects of ambient air pollution exposure on frequency of hospital admissions for appendicitis in Taipei,Taiwan

The relationship between exposure to ambient air pollutants and hospital admissions for appendicitis is not known. This study examined whether an association existed between air contaminant levels and frequency of hospital admissions for appendicitis in Taipei, Taiwan. Ambient air pollution and hospital admission data for Taipei were obtained for 2009–2013. Relative risk (RR) of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single pollutant model, on warm days (> 23°C), number of appendicitis admissions was significantly associated with particulate matter (PM_2.5), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). On cool days (< 23°C), a significant rise in number of admissions for appendicitis was related to PM₁₀, NO₂, and O₃ concentrations. In the two-pollutant models, on warm days, NO₂ and O₃ were significantly associated with increased number of admissions for appendicitis when combined with each of the other pollutants. On cool days, NO₂, O₃, and PM₁₀ remained significant for higher appendicitis admission cases in all two-pollutant models. In conclusion, higher levels of ambient air pollutants may be associated with increase in the risk of hospital admissions for appendicitis in Taipei.     

Short-term effects of ozone air pollution on hospital admissions for myocardial infarction: A time-stratified case-crossover study in Taipei

This study was undertaken to determine whether there was a correlation between ambient ozone (O₃) levels and number of hospital admissions for myocardial infarction (MI) in Taipei, Taiwan. Hospital admissions for MI and ambient air pollution data for Taipei were obtained for the period from 2006 to 2010. The relative risk (RR) of hospital admissions for MI was estimated using a time-stratified case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased RR for a number of MI admissions was significantly associated with higher O₃ levels both on warm days (>23°C) and on cool days (<23°C). This observation was accompanied by an interquartile range elevation correlated with a 7% (95% CI = 2%–12%) and 17% (95% CI = 11%–25%) rise in number of MI admissions, respectively. In the two-pollutant models, no significant associations between ambient O₃ concentrations and number of MI admissions were observed on warm days. However, on cool days, correlation between ambient O₃ after inclusion of each of the other five pollutants, particulate matter (PM₁₀ or PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂) or carbon monoxide (CO), and number of MI admissions remained significant. This study provides evidence that higher levels of ambient O₃ increase the RR of number of hospital admissions for MI.     

Association between gaseous air pollution and hospital admissions for hypertension in Taipei,Taiwan

Air pollution exposure has been reported to influence blood pressure. However, only a few epidemiological studies demonstrated association between ambient air pollution exposure and acute hypertensive events. The aim of this study was to examine the association between gaseous air pollutants exposure and hospital admissions for hypertension in Taipei, Taiwan. Data on hospital admissions for hypertension and ambient air pollution in Taipei were obtained for the 2009–2013 period. An odds ratio (OR) for number of hospital admissions for hypertension associated with each interquartile range increase in each gaseous air pollutant was calculated using a case-crossover approach, after controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant model, significant correlation was observed between number of hospital admissions for hypertension and ozone (O₃) levels both on warm (>23°C) and cool (<23°C) days, with OR of 1.2 (95% confidence interval [CI] = 1.03–1.4) and 1.2 (95% CI = 1.02–1.42), respectively. No significant associations were found between levels of other gaseous pollutants and risk of hospital admissions for hypertension. In the two-pollutant model, O₃ levels remained significant after inclusion of particulate matter 10 μm or less in diameter (PM₁₀), sulfur dioxide (SO₂), or carbon monoxide (CO) on warm days. On cool days, O₃ levels remained significant after inclusion of air pollutants other than SO₂. These findings indicated that O₃ exposure may trigger a rise in blood pressure to a level that results in higher number of hospital admissions.     

Air Pollution and Hospital Admissions for Pneumonia in a Subtropical City: Taipei,Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and hospital admissions for pneumonia in Taipei, Taiwan. Hospital admissions for pneumonia and ambient air pollution data for Taipei were obtained for the period from 1996–2004. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single pollutant models, on warm days (>23°C) statistically significant positive associations were found in all pollutants. On cool days (<23°C), all pollutants were significantly associated with pneumonia admissions except SO₂. For the two-pollutant model, O₃ and NO₂ were significant in combination with each of the other 4 pollutants on warm days. On cool days, PM_{1 0}, CO, and O₃ remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for pneumonia.     

Association between ozone air pollution levels and hospitalizations for depression in Taipei: a time-stratified case-crossover study

ABSTRACT

Epidemiologic studies reported an association between exposure to ambient air pollutants and increased mortality rate attributed to suicide and suicide attempts. The investigation sought to determine whether there is an association between short-term ambient ozone (O₃) level exposure and daily hospital admissions for depression in Taipei from 2009 to 2013 using a time-stratified case-crossover design. In our single-pollutant model (with no adjustment for other pollutants), the % increase in daily hospital admissions for depression was 12% on warm days and 30% on cool days, per interquartile range (IQR) rise in O₃ levels, respectively. Ozone levels were significantly correlated with daily number of depression admissions both on warm and cool days. In our two-pollutant models, O₃ levels remained significant after adjusting for other air pollutants, including particulate matter (PM₁₀, PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO) both on warm and cool days. Although O₃ levels tended to be higher on warm days, admissions for depression were higher on cool days, suggesting that the relationship between O₃ concentrations and depression may be affected by temperature. Further study is needed to better understand these findings.     

Fine particulate air pollution associated with increased risk of hospital admissions for hypertension in a tropical city,Kaohsiung, Taiwan

The aim of this study was to assess whether a correlation exists between fine particles (PM_2.5) levels and number of hospital admissions for hypertension in Kaohsiung, Taiwan. Hospital admission frequency and ambient air pollution data were obtained for Kaohsiung for 2009–2013. A time-stratified case-crossover method was used to estimate relative risk for hospital admissions, controlling for weather, day of the week, seasonality, and long-term time trends. Odds ratios and 95% confidence intervals were calculated for a 10 µg/m³ increment of PM_2.5 for lags from days 0 to 6. Data showed no significant associations between PM_2.5 levels and number of hypertension-related hospital admissions on warm days (>25°C). However, on cool days (<25°C), a significant positive association was found with frequency of hypertension admissions in the single-pollutant model (without adjusting for other pollutants) with a 10 µg/m³ rise in PM_2.5 on day of admission (lag 0) associated with a 12% increase in number of admissions for hypertension. In the two-pollutant model, the association of PM_2.5 with rate of hypertension hospitalizations remained significant after including SO₂ or O₃ on lag day 0. Data demonstrate that an association between short-term exposure to PM_2.5 and elevated risk of hypertension-related hospital admissions may exist in Kaohsiung, Taiwan, a tropical city.     

Air Pollution and Hospital Admissions for Congestive Heart Failure in a Tropical City: Kaohsiung,Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and hospital admissions for congestive heart failure (CHF) in Kaohsiung, Taiwan. Hospital admissions for CHF and ambient air pollution data for Kaohsiung were obtained for the period 1996–2004. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant models, on warm days (> 25°C) statistically significant positive associations were found in all pollutants except sulfur dioxide (SO₂). On cool days (< 25°C), all pollutants were significantly associated with CHF admissions. For the two-pollutant model, CO and O₃ were significant in combination with each of the other four pollutants on warm days. On cool days, NO₂ remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for CHF and that the effects of air pollutants on hospital admissions for CHF were temperature dependent.     

Air pollution and hospital admissions for pneumonia: Are there potentially sensitive groups?

Recent studies have shown that air pollution is a risk factor for hospitalization for pneumonia. However, there is limited evidence to suggest what subpopulations are at greater risk from air pollution. This study was undertaken to examine the modifying effect of specific secondary diagnosis (including hypertension, diabetes, asthma, and upper respiratory infections) on the relationship between hospital admissions for pneumonia and ambient air pollutants. Hospital admissions for pneumonia and ambient air pollution data for Kaohsiung were obtained for the period 1996–2006. The relative risk of hospital admission was estimated using a case-crossover approach. We found that an interquartile range (IQR) increase in PM₁₀, NO₂, and CO on warm days was associated with a 28% (95% confidence interval [CI], 11–48%), 40% (95% CI, 20–63%), and 31% (95% CI, 19–45%), respectively, increase in admissions for pneumonia with upper respiratory infections (URI), but only 23% (95% CI, 18–28%), 30% (95% CI, 25–36%), and 24% (95% CI, 21–28%), respectively, increase for persons without URI. An IQR increase in PM₁₀, SO₂, and CO on cool days was associated with a 70% (95% CI, 50–92%), 30% (95% CI, 15–47%), and 64% (95% CI, 47–83%), respectively, increase in admissions in persons with URI, and an increase of 64% (95% CI, 57–70%), 18% (95% CI, 14–22%), and 55% (95% CI, 50–60%), respectively, in admissions in persons without URI. Our findings provide evidence that patients with comorbid URI may increase the risk of hospital admissions for pneumonia, in relation to air pollutant levels.     

Air pollution and hospital admissions for congestive heart failure in a subtropical city: Taipei, Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and hospital admissions for congestive heart failure (CHF) in Taipei, Taiwan. Hospital admissions for CHF and ambient air pollution data for Taipei were obtained for the period from 1996 to 2004. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant model, the number of CHF admissions was significantly associated with the environmental presence of the contaminants particulate matter (PM(10)), nitrogen dioxide (NO(2)), carbon monoxide (CO), and ozone (O(3)) on warm days (>20 degrees C). However, statistically significant positive effects on increased CHF admissions on cool days (<20 degrees C) was observed only for CO levels. For the two-pollutant model, NO(2) and O(3) were significant in combination with each of the other four pollutants on warm days for enhanced CHF admissions. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for CHF.     

Air pollution and hospital admissions for pneumonia in a subtropical city: Taipei, Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and hospital admissions for pneumonia in Taipei, Taiwan. Hospital admissions for pneumonia and ambient air pollution data for Taipei were obtained for the period from 1996-2004. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single pollutant models, on warm days (>23 degrees C) statistically significant positive associations were found in all pollutants. On cool days (<23 degrees C), all pollutants were significantly associated with pneumonia admissions except SO(2). For the two-pollutant model, O(3) and NO(2) were significant in combination with each of the other 4 pollutants on warm days. On cool days, PM(10), CO, and O(3) remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for pneumonia.     

Air pollution and emergency room visits for cardiac arrhythmia in a subtropical city: Taipei,Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and emergency room (ER) visits for cardiac arrhythmia in Taipei, Taiwan. ER visits for cardiac arrhythmia and ambient air pollution data for Taipei were obtained for the period 2000–2006. The relative risk of ER visits was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant model, on warm days (≥23°C), statistically significant positive associations were found for all pollutants except SO₂. On cool days (<23°C), all pollutants were also significantly associated with the number of ER visits for cardiac arrhythmia, except SO₂. For the two-pollutant model, results for O₃ and NO₂ remained statistically significant on both warm and cool days. This study provides evidence that higher levels of ambient air pollutants increase the risk of ER visits for cardiac arrhythmia.     

Effects of Asian Dust Storm Events on Hospital Admissions for Chronic Obstructive Pulmonary Disease in Taipei,Taiwan

In spring, windblown dust storms originating in the deserts of Mongolia and China make their way to Taipei city. These occurrences are known as Asian dust storm (ADS) events. These ADS events lead to enhanced PM₁₀ levels over that contributed by the usual local sources. The objective of this study was to assess the possible associations of PM₁₀ with hospital admissions for chronic obstructive pulmonary disease (COPD) in Taipei, Taiwan, during the period 1996–2001. We identified 54 dust storm episodes that were classified as index days. Daily COPD admissions on the index days were compared with admissions on the comparison days. We selected 2 comparison days for each index day, 7 days before the index days and 7 days after the index days. The effects of dust storms on hospital admissions for COPD were prominent 3 days after the event (relative risk = 1.057; 95% confidence interval = 0.982–1.138). However, the association was not statistically significant. There may not have been enough power to detect associations resulting from the inadequate sample size of COPD admissions on ADS events days. However, It seems worthwhile to pay more attention to the ADS events and health in the future.     

Air pollution and hospital admissions for asthma in a subtropical city: Taipei, Taiwan

This study was undertaken to determine whether there is an association between exposure to air pollutants levels and number of hospital admissions for asthma in Taipei, Taiwan. Hospital admissions for asthma and ambient air pollution data for Taipei were obtained for the period from 1996 through 2003. The relative risk of hospital admission for asthma was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-air-pollutant model, on warm days (> or = 25 degrees C) statistically significant positive associations were found for SO2, NO2, and CO levels with an increase in asthmatic admissions. On cool days (< 25 degrees C), all air pollutants were significantly associated with elevated asthma admissions except SO2. For the two-air-pollutant model, CO significantly increases hospital admissions for asthma in combination with each of the other four pollutants on warm days. On cool days, NO2 and O3 significantly elevated asthma rates in all the two-air-pollutant models. This study provides evidence that higher levels of ambient air pollutant concentrations increase the risk of hospital admissions for asthma.     

Air Pollution and Hospital Admissions for Chronic Obstructive Pulmonary Disease in a Tropical City: Kaohsiung,Taiwan

This study was undertaken to determine whether there is an association between air pollutants levels and hospital admissions for chronic obstructive pulmonary disease (COPD) in Kaohsiung, Taiwan. Hospital admissions for COPD and ambient air pollution data for Kaohsiung were obtained for the period from 1996 to 2003. The odds ratio of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant models, on warm days (≥25°C) statistically significant positive associations were found in all pollutants except sulphur dioxide (SO₂). On cool days (< 25°C), all pollutants were significantly associated with COPD admissions. For the two-pollutant models, CO and O₃ were significant in combination with each of the other four pollutants on warm days. On cool days, NO₂ remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient pollutants increase the risk of hospital admissions for COPD.     

Association between Air Pollution and Multiple Respiratory Hospitalizations among the Elderly in Vancouver,Canada

Recurrent events, such as repeated hospital admissions for the same health outcome, occur frequently in environmental health studies. In this study, we conducted an analysis of data on repeated respiratory hospitalizations among the elderly in Vancouver, Canada, for the period of June 1, 1995, to March 31, 1999, using a new method proposed by () for recurrent events, and compared it with some traditional methods. In particular, we assessed the impact of ambient gaseous (SO₂, NO₂, CO, and O₃) and particulate pollutants (PM₁₀, PM_2.5, and PM_10–2.5) as well as the coefficient of haze (CoH) on recurrent respiratory hospital admissions. Using the new procedure, significant associations were found between admissions and 3-day, 5-day, and 7-day moving averages of the ambient SO₂ concentrations, with the strongest association observed at the 7-day lag (RR = 1.044, 95% CI: 1.018–1.070). We also found PM_10–2.5 for 3-day and 5-day lag to be significant, with the strongest association at 5-day lag (RR = 1.020, 95% CI: 1.001–1.039). No significant associations with admission were found with current day exposure.     

Air pollution and hospital admissions for congestive heart failure in a tropical city: Kaohsiung, Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and hospital admissions for congestive heart failure (CHF) in Kaohsiung, Taiwan. Hospital admissions for CHF and ambient air pollution data for Kaohsiung were obtained for the period 1996-2004. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant models, on warm days (> 25 degrees C) statistically significant positive associations were found in all pollutants except sulfur dioxide (SO(2)). On cool days (< 25 degrees C), all pollutants were significantly associated with CHF admissions. For the two-pollutant model, CO and O(3) were significant in combination with each of the other four pollutants on warm days. On cool days, NO(2) remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient air pollutants increase the risk of hospital admissions for CHF and that the effects of air pollutants on hospital admissions for CHF were temperature dependent.     

The Effect of Coarse Ambient Particulate Matter on First,Second, and Overall Hospital Admissions for Respiratory Disease Among the Elderly

Abstract

The objective of this article is to examine differences in the effect of ambient particulate matter on first, second, and overall hospital admissions for respiratory disease among the elderly. We studied 8989 adults 65 yr of age or older living in the greater Vancouver area who were admitted to hospital for any acute respiratory disease (ICD-9 codes 460–519) between June 1, 1995, and March 31, 1999. Time-series analysis was used to evaluate the association between respiratory admissions and daily measures of particulate matter (PM₁₀, PM_2.5, and PM_{10 ? 2.5}) in urban air, after adjustment for gaseous copollutants (CO, O₃, NO₂, and SO₂) and meteorological variables. Repeated admissions for respiratory disease were common among the elderly. Approximately 30% of the subjects were readmitted to hospital after the first admission; 9% had more than 2 admissions for respiratory disease during the 4-yr study period. PM_{10 ? 2.5} was significantly associated with the second and overall admissions for respiratory disease, but not with the first admission. The adjusted relative risks for an increment of 4.2 μ g/m³ in -day average PM_{10 ? 2.5} concentrations were 1.03 (95% confidence interval: 0.98–1.09) for the first admission, 1.22 (1.10–1.36) for the second admission, and 1.06 (1.02, 1.11) for overall admissions. There was no significant association between PM_2.5 and hospital admissions for respiratory disease among the elderly. Our data suggest that (1) people with a history of respiratory admissions are at a higher risk of respiratory disease in relation to particulate air pollution in urban areas, (2) analyses based on overall rather than repeated hospital admissions lead to lower estimates of the risk of respiratory disease associated with particulate air pollution, and (3) PM_{10 ? 2.5} has a larger effect on respiratory admissions than PM_2.5.     

Influence of Relatively Low Level of Particulate Air Pollution on Hospitalization for COPD in Elderly People

To assess the association between relatively low levels of size-fractioned particulate matter (PM) and hospitalization for chronic obstructive pulmonary disease (COPD), we conducted a time-series analysis among elderly people 65 yr of age or more living in Vancouver between June 1995 and March 1999. Measures of thoracic PM (PM₁₀), fine PM (PM_2.5), coarse PM (PM_10?2.5), and coefficient of haze (COH) were examined over periods varying from 1 to 7 days prior to hospital admissions. Generalized additive models (GAMs; general linear models, GLMs) were used, and temporal trends and seasonal and subseasonal cycles in COPD hospitalizations were removed by using GLM with parametric natural cubic splines. The relative risks were calculated based on an incremental exposure corresponding to the interquartile range of these measures, and were adjusted for daily weather conditions and gaseous pollutants. PM measures had a positive effect on COPD hospitalization, especially 0 to 2 days prior to the admissions, before copollutants were accounted for. For 3-day average levels of exposure the relative risk estimates were 1.13 (95% confidence interval: 1.05–1.21) for PM₁₀, 1.08 (1.02–1.15) for PM_2.5, 1.09 (1.03–1.16) for PM_10?2.5, and 1.05 (1.01–1.09) for COH. The associations were no longer significant when NO₂ was included in the models. We concluded that the particle-related measures were significantly associated with COPD hospitalization in the Vancouver area, where the level of air pollution is relatively low, but the effects were not independent of other air pollutants.