Ambient air pollution exposure and COVID-19 related hospitalizations in Santiago, Chile.

Morbidity and mortality from several diseases are increased on days of higher ambient air pollution. We carried out a daily time-series analysis with distributive lags to study the influence of short-term air pollution exposure on COVID-19 related hospitalization in Santiago, Chile between March 16 and August 31, 2020. Analyses were adjusted for temporal trends, ambient temperature, and relative humidity, and stratified by age and sex. 26,579 COVID-19 hospitalizations were recorded of which 24,501 were laboratory confirmed. The cumulative percent change in hospitalizations (95% confidence intervals) for an interquartile range increase in air pollutants were: 1.1 (0.2, 2.0) for carbon monoxide (CO), 0.30 (0.0, 0.50) for nitrogen dioxide (NO2), and 2.7 (1.9, 3.0) for particulate matter of diameter ≤ 2.5 microns (PM2.5). Associations with ozone (O3), particulate matter of diameter ≤ 10 microns (PM10) and sulfur dioxide (SO2) were not significant. The observed effect of PM2.5 was significantly greater for females and for those individuals ≥ 65 years old. This study provides evidence that daily increases in air pollution, especially PM2.5, result in a higher observed risk of hospitalization from COVID-19. Females and the elderly may be disproportionately affected.

The association between air pollution and COVID-19 related mortality in Santiago, Chile: A daily time series analysis.

BACKGROUND: Exposure to ambient air pollution is a risk factor for morbidity and mortality from lung and heart disease. RESEARCH QUESTION: Does short term exposure to ambient air pollution influence COVID-19 related mortality? STUDY DESIGN AND METHODOLOGY: Using time series analyses we tested the association between daily changes in air pollution measured by stationary monitors in and around Santiago, Chile and deaths from laboratory confirmed or suspected COVID-19 between March 16 and August 31, 2020. Results were adjusted for temporal trends, temperature and humidity, and stratified by age and sex. RESULTS: There were 10,069 COVID-19 related deaths of which 7659 were laboratory confirmed. Using distributed lags, the cumulative relative risk (RR) (95% CI) of mortality for an interquartile range (IQR) increase in CO, NO2 and PM2.5 were 1.061 (1.033-1.089), 1.067 (1.023-1.103) and 1.058 (1.034-1.082), respectively There were no significant differences in RR by sex.. In those at least 85 years old, an IQR increase in NO2 was associated with a 12.7% (95% CI 4.2-22.2) increase in daily mortality. CONCLUSION: This study provides evidence that daily increases in air pollution increase the risk of dying from COVID-19, especially in the elderly.

The association between air pollution and hospitalization for patients with systemic lupus erythematosus in Chile: A daily time series analysis.

Genetic and environmental factors are thought to influence the activity of systemic lupus erythematosus (SLE), but relatively little is known about the effects of ambient air pollution. Using pollution data from air monitoring stations in the urban centers in Santiago Chile, along with daily patient hospitalization data from 2001 to 2012, an association between ambient air pollution and daily hospital admissions for SLE was tested using generalized linear models. Averaged over all regions pollutant mean 24 h concentrations were: 0.96 ppm carbon monoxide (CO), 64 ppb ozone (O3), 43 ppb nitrogen dioxide (NO2), 9 ppb sulphur dioxide (SO2), 29 µg/m3 particulate matter ≤ 2.5 µm in mean aerodynamic diameter (PM2.5), and 67 µg/m3 particulate matter ≤ 10 µm in diameter (PM10). The relative risk estimates in single pollutant models for an interquartile range (IQR) increase in pollutant were: RR = 1.34 (95% CI: 1.06-1.83) for SO2, RR = 1.60 (95% CI: 1.15-2.24) for CO, and RR = 1.41 (95% CI: 1.14-1.86) for PM2.5. In two-pollutant models, the significance of SO2 and PM2.5 persisted despite adjustments for each of the other measured pollutants. These findings suggest that acute increases in air pollution increase the risk of hospitalization with a primary diagnosis of SLE.

The Association Between Air Pollution and Hospitalization of Patients With Idiopathic Pulmonary Fibrosis in Chile: A Daily Time Series Analysis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) causes progressive dyspnea, hypoxemia, and death within a few years. Little is known about the effect of air pollution on disease exacerbations. RESEARCH QUESTION: Are acute increases in air pollution a risk factor for hospitalization of patients with a primary diagnosis of IPF. STUDY DESIGN AND METHODS: Hospital admissions for IPF are coded J84.1 by the International Classification of Disease, 10th Revision. Using ambient air pollution and climate data from seven air monitoring stations distributed in the seven urban centers in Santiago, Chile, along with daily patient hospitalization data from 2001 to 2012, a linear association between daily ambient air pollution and daily J84.1 hospital admissions was tested using generalized linear models. RESULTS: Average pollutant levels for all regions were as follows: carbon monoxide was 0.96 ppm, ozone was 64 ppb, nitrogen dioxide (NO2) was 43 ppb, sulfur dioxide was 9 ppb, particulate matter < 2.5 µm in diameter was 29 µg/m3 and particulate matter < 10 µm in diameter (PM10) was 67 µg/m3. For the combined Santiago area, relative risk estimates of J84.1 hospitalizations for all pollutants (except ozone), adjusted for age, sex, and weather were statistically significant. In the two-pollutant models, the significance of NO2 and PM10 persisted despite adjustments for each of the other measured pollutants. INTERPRETATION: Our findings suggest that acute increases in air pollution are a risk factor for hospitalization of patients with a primary diagnosis of IPF.

Air pollution and hospitalization for acute complications of diabetes in Chile.

Exposure to air pollution has been shown to cause insulin resistance in mice. To determine the relevance to humans, we tested the association between daily air pollution concentrations and daily hospitalization for acute serious complications of diabetes, coma and ketoacidosis, in Santiago between 2001 and 2008, using generalized linear models with natural splines to control for long term trends. For an interquartile range (IQR) increase in air pollutant, the relative risks (95% CI) of hospitalization for diabetes were: 1.15 (1.10, 1.20) for carbon monoxide (IQR=1.00); 1.07 (0.98, 1.16) for ozone (IQR=63.50); 1.14 (1.06, 1.22) for sulfur dioxide (IQR=5.88); 1.12(1.05, 1.20) for nitrogen dioxide (IQR=27.94); 1.11 (1.07, 1.15) for particulate matter≤10 µm diameter(IQR=34.00); and 1.11 (1.06, 1.16) for fine particulate matter ≤2.5 µm diameter (IQR=18.50). Results were similar when stratified by age, sex and season. Air pollution appears to increase the risk of acute complications of diabetes requiring hospitalization, suggesting that improvements in air quality may reduce morbidity from diabetes.

The risk of dying on days of higher air pollution among the socially disadvantaged elderly.

RATIONALE: The estimated mortality rate associated with ambient air pollution based on general population studies may not be applicable to certain subgroups. OBJECTIVE: The objective of the present study was to determine the influence of age, education, employment status and income on the risk of mortality associated with ambient air pollution. METHODS: Daily time-series analyses tested the association between daily air pollution and daily mortality in seven Chilean urban centers during the period January 1997-December 2007. Results were adjusted for long-term trends, day-of-the week and humidex. RESULTS: Interquartile increases in particulate matter (PM(10) and PM(2.5)), sulphur dioxide, nitrogen dioxide, carbon monoxide, and elemental and organic carbon were associated with a 4-7% increase in mortality among those who did not complete primary school (p<0.05) vs. 0.5-1.5% among university graduates (p>0.05). Among those at least 85 years of age respective estimates were 2-7%. However, among the elderly who did not complete primary school, respective estimates were 11-19% (p<0.05). The degree of effect modification was less for income and employment status than education, and sex did not modify the results. CONCLUSION: The socially disadvantaged, especially if elderly appear to be especially susceptible to dying on days of higher air pollution. Concentrations deemed acceptable for the general population would not appear to protect this susceptible subgroup.

Air pollution and hospitalization for epilepsy in Chile.

OBJECTIVE: To determine the association between gaseous and fine particulate air pollution (PM(2.5)) and epilepsy in a general population sample. METHOD: A daily time-series analyses tested the association between daily hospitalization for epilepsy in seven Chilean urban centers during the period 2001 and 2005. Results were adjusted for long term trends, day-of-the-week, and average humidex on the day of hospitalization and the day before. RESULTS: Pooled city estimates of relative risk (95% CI) of hospitalization for epilepsy associated with changes in pollutant concentrations equivalent to their interquartile range were: 1.098(1.045, 1.155) for carbon monoxide (CO); 1.100 (1.025, 1.181) for ozone O(3); 1.085 (1.03, 1.144) for sulfur dioxide (SO(2)); 1.108 (1.021, 1.204) for nitrogen dioxide (NO(2)); 1.083(1.038, 1.13) for particulate matter

Components of particulate air pollution and emergency department visits in Chile.

The objective of the present study was to determine the association between several elements of particulates and Emergency Department (ED) visits in a general population sample. Daily time-series analyses tested the association between daily ED visit and air pollutants and components of particulates measured in Santiago Centro, a municipality, which includes downtown Santiago during the period from 2001 to 2006. The strongest individual effect was seen for elemental carbon. A 4.76 microg/m3 increase was associated with a relative risk (RR) of 1.12 (95% confidence interval [CI] = 1.10-1.14) increase in total ED visits, and a RR of 1.18 (95% CI = 1.16-1.21) for respiratory ED visit. Using factor analysis, the authors determined that traffic combustion-related particulates were significantly associated with ED visits. Among all the sources identified, traffic combustion-related particulates had the strongest association with ED visits. A factor indicating soil-sourced particles had a weaker but statistically significant observed morbidity effect. Of the many components of particulate air pollution, those from motor vehicle exhaust had the greatest observed effect on morbidity.

Air pollution and hospitalization for headache in Chile.

The authors performed a time-series analysis to test the association between air pollution and daily numbers of hospitalizations for headache in 7 Chilean urban centers during the period 2001-2005. Results were adjusted for day of the week and humidex. Three categories of headache-migraine, headache with cause specified, and headache not otherwise specified-were all associated with air pollution. Relative risks for migraine associated with interquartile-range increases in specific air pollutants were as follows: 1.11 (95% confidence interval (CI): 1.06, 1.17) for a 1.15-ppm increase in carbon monoxide; 1.11 (95% CI: 1.06, 1.17) for a 28.97-microg/m(3) increase in nitrogen dioxide; 1.10 (95% CI: 1.04, 1.17) for a 6.20-ppb increase in sulfur dioxide; 1.17 (95% CI: 1.08, 1.26) for a 69.51-ppb increase in ozone; 1.11 (95% CI: 1.00, 1.19) for a 21.51-microg/m(3) increase in particulate matter less than 2.5 mum in aerodynamic diameter (PM(2.5)); and 1.10 (95% CI: 1.04, 1.15) for a 37.79-microg/m(3) increase in particulate matter less than 10 mum in aerodynamic diameter (PM(10)). There was no significant effect modification by age, sex, or season. The authors conclude that air pollution appears to increase the risk of headache in Santiago Province. If the relation is causal, the morbidity associated with headache should be considered when estimating the burden of illness and costs associated with poor air quality.

Components of particulate air pollution and mortality in Chile.

To determine the association between several elements of fine particulate air pollution (PM2.5) and mortality in a general population sample, daily time-series analysis was used to test the association between daily mortality and components of PM2.5 measured in downtown Santiago, Chile between 1998 and 2006. The strongest individual effect was seen for elemental carbon. A 5.28 ug/m3 increase in elemental carbon was associated with a relative risk (RR) of 1.08 (95% CI = 1.07-1.09) for total non-accidental mortality. Using factor analysis, a group of elements consistent with a mobile combustion source (carbon monoxide, nitrogen dioxide, elemental and organic carbon) was significantly associated with total mortality (RR 1.11; 95% CI = 1.083-1.138). Soil-sourced particles had a weaker but statistically significant mortality effect. Of the many sources of particulate air pollution, those from motor vehicle exhaust had the greatest observed effect on mortality.

Air pollution and mortality in Chile: susceptibility among the elderly.

OBJECTIVE: The estimated mortality rate associated with ambient air pollution based on general population studies may not be representative of the effects on certain subgroups. The objective of the present study was to determine the influence of relatively high concentrations of air pollution on mortality in a general population sample and in the very elderly. STUDY DESIGN: Daily time-series analyses tested the association between daily air pollution and daily mortality in seven Chilean urban centers during 1997-2003. Results were adjusted for day of the week and humidex. RESULTS: Daily averaged particulate matter with aerodynamic matter < 10 microm (PM(10)) was 84.88 microg/m(3), sulfur dioxide was 14.08 ppb, and carbon monoxide was 1.29 ppb. The 1-hr maximum ozone was 100.13 ppb. The percentage increases in nonaccidental mortality associated with an increase in PM(10) equivalent to its mean were 4.53 (t-ratio 1.52) for those < 65 years and 14.03 (3.87) for those > 85 years. Respective values were 4.96 (1.17) and 8.56 (2.02) for O(3); 4.77 (2.50) and 7.92 (3.23) for SO(2); and 4.10 (2.52) and 8.58 (4.45) for CO. CONCLUSION: Our results suggest that the very elderly are particularly susceptible to dying from air pollution. Concentrations deemed acceptable for the general population may not adequately protect the very elderly.