Increased Risk of Hospital Admission for Asthma in Children From Short-Term Exposure to Air Pollution: Case-Crossover Evidence From Northern China

Abstract

Background: Previous studies suggested that exposure to air pollution could increase risk of asthma attacks in children. The aim of this study is to investigate the short-term effects of exposure to ambient air pollution on asthma hospital admissions in children in Beijing, a city with serious air pollution and high-quality medical care at the same time.Methods: We collected hospital admission data of asthma patients aged ≤ 18 years old from 56 hospitals from 2013 to 2016 in Beijing, China. Time-stratified case-crossover design and conditional Poisson regression were applied to explore the association between risk of asthma admission in children and the daily concentration of six air pollutants [particulate matter ≤ 2.5 μm (PM2.5), particulate matter ≤ 10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3)], adjusting for meteorological factors and other pollutants. Additionally, stratified analyses were performed by age, gender, and season.Results: In the single-pollutant models, higher levels of PM2.5, SO2, and NO2 were significantly associated with increased risk of hospital admission for asthma in children. The strongest effect was observed in NO2 at lag06 (RR = 1.25, 95%CI: 1.06-1.48), followed by SO2 at lag05 (RR = 1.17, 95%CI: 1.05–1.31). The robustness of effects of SO2 and NO2 were shown in two-pollutant models. Stratified analyses further indicated that pre-school children (aged ≤ 6 years) were more susceptible to SO2. The effects of SO2 were stronger in the cold season, while the effects of NO2 were stronger in the warm season. No significant sex-specific differences were observed.Conclusions: These results suggested that high levels of air pollution had an adverse effect on childhood asthma, even in a region with high-quality healthcare. Therefore, it will be significant to decrease hospital admissions for asthma in children by controlling air pollution emission and avoiding exposure to air pollution.

Associations between air pollutant and pneumonia and asthma requiring hospitalization among children aged under 5 years in Ningbo, 2015–2017

“…Our study was not without some seasonal heterogeneity. Generally, the adverse effects of PM 2.5 , PM 10 , and NO 2 were noted to be slightly higher in warmer as compared to colder months, consistent with findings reported by previous studies performed in Beijing ( 79 ), Fuzhou ( 80 ), Taiwan ( 81 ), and Hong Kong ( 82 ). The reasons why air pollutants are more harmful in a warmer season can be explained by high temperature itself being associated with increased risk of pneumonia ( 83 ).…”

Air pollution and childhood asthma

“…The main culprit in that study was the gaseous air pollutant, sulfur dioxide (SO 2 ), particularly in the younger age group [31]. Zhao et al [33] demonstrated an increased risk for pediatric asthma hospitalization with higher levels of short-term exposure to PM 2.5 , SO 2 and NO 2 [32]. The impact of smaller particles size was demonstrated by a recent study conducted in China, where the smaller the particle size the stronger the observed effect estimates associated with increased outpatient department visits due to asthma.…”

Hourly Valley Concentration of Air Pollutants Associated with Increased Acute Myocardial Infarction Hospital Admissions in Beijing, China

“…Influenza was independently linked to a higher risk of AMI according to prior research [21], and meteorological factors had an adverse effect on cardiovascular diseases [21][22][23][24], so the influenza endemic, daily mean temperature, and relative humidity were regarded as the confounding factors and were adjusted in our statistical model. When the positive rate of influenza virus isolation in any given week exceeded 20% of the highest weekly positive rate in the observation season in the north of China, it was defined as the influenza endemic (IF) [25,26], based on the data provided by the Chinese National Influenza Center [27]. The China Meteorological Administration provided the daily mean temperature and relative humidity.…”