Severe and Moderate Asthma Exacerbations in Asthmatic Children and Exposure to Ambient Air Pollutants

Abstract

Background: It is well established that short-term exposure to ambient air pollutants can exacerbate asthma, the role of early life or long-term exposure is less clear. We assessed the association between severe asthma exacerbations with both birth and annual exposure to outdoor air pollutants with a population-based cohort of asthmatic children in the province of Quebec (Canada). Method: Exacerbations of asthma occurring between 1 April 1996 and 31 March 2011 were defined as one hospitalization or emergency room visit with a diagnosis of asthma for children (<13 years old) already diagnosed with asthma. Annual daily average concentrations of ozone (O3) and nitrogen dioxide (NO2) were estimated at the child’s residential postal code. Satellite based levels of fine particulate (PM2.5) estimated for a grid of 10 km by 10 km were also assigned to postal codes of residence for the whole province. Hazard ratios (HRs) were estimated from Cox models with a gap time approach for both birth and time-dependant exposure. Results: Of the 162,752 asthmatic children followed (1,020,280 person-years), 35,229 had at least one asthma exacerbation. The HRs stratified by age groups and adjusted for the year of birth, the ordinal number of exacerbations, sex, as well as material and social deprivation, showed an interquartile range increase in the time-dependant exposure to NO2 (4.95 ppb), O3 (3.85 ppb), and PM2.5 (1.82 μg/m3) of 1.095 (95% CI 1.058–1.131), 1.052 (95% CI 1.037–1.066) and 1.025 (95% CI 1.017–1.031), respectively. While a positive association was found to PM2.5, no associations were found between exposure at birth to NO2 or O3. Conclusions: Our results support the conclusion, within the limitation of this study, that asthma exacerbations in asthmatic children are mainly associated with time dependent residential exposures less with exposure at birth.

Atmospheric Pollution and Hospitalization for Cardiovascular and Respiratory Diseases in the City of Manaus from 2008 to 2012

“…e adverse effects of PM on hospitalizations for cardiovascular disease were correlated with the same day of pollutant increase (lag 0) and decreased the risk on subsequent days [27][28][29][30]. e present study also differs from the academic literature that shows an association between PM 2.5 and the increase in hospitalization for cardiorespiratory diseases [31][32][33]. e literature shows that for children, an increase in the PM 2.5 level increased the number of hospitalizations for respiratory diseases [34][35][36][37].…”

Nexus between Air Pollution and Neonatal Deaths: A Case of Asian Countries

“…Ambient air pollution (PM 2.5 ) severely victimizes people having a history of respiratory disease like chronic obstructive pulmonary disease (COPD) [5,18]. The literature has validated the contributive impact of air pollution (PM 2.5 ) in onset of various respiratory diseases like respiratory infection, chronic obstructive pulmonary disease (COPD), asthma, and lung cancer [19,20,21,22,23]. [24] found strong association between air pollution and respiratory disease mortalities and outpatient visits in southeastern China.…”

Assessing the impact of air pollution on childhood asthma morbidity: how, when, and what to do

“…NO 2 is generated by automobiles and gas heaters and cooking ranges. Recent studies have shown a link between NO 2 exposure and reduced lung function (3*, 4*), increased need for rescue medications (28), and elevated risk and severity of asthma exacerbations (9, 11, 29). Gaffin et al reported that for every 10 ppb increase in classroom NO 2 concentration, there was a 5% reduction in FEV 1 /Forced Vital Capacity (FVC) ratio; classroom NO 2 was inversely associated with Forced Expiratory Flow at 25–75% of lung volume (FEF 25- 75) in this study (3*).…”