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Multiple outdoor environmental factors and asthma exacerbations

Published online: September 16, 2019

Asthma exacerbations (AEs) are especially common in young and elderly individuals, and are associated with seasonal variations of environmental factors, such as weather conditions, aeroallergens, ambient air pollution and burden of respiratory virus infection. Although previous studies have identified these individual factors associated with the risk of AEs, no comprehensive study has examined the effects all of these factors on AEs.

In the original research recently published in The Journal of Allergy and Clinical Immunology (JACI), Lee and Yon et al. investigated an age-stratified analysis of the short-term effects of four groups (infants, preschool children, school-aged children, adults, and elderly) of outdoor environmental factors on AEs in Seoul Metropolitan City (Korea) from 2008 and 2012 (n=10,233,519).

The authors found that the different age groups had differences in their sensitivity to the different environmental factors, that PM10 had the greatest effect on AE events, and that these effects were greatest and almost immediate in infants, but tended to decline with patient age. Diurnal temperature range had significant effects in pediatric (infants, preschool children, and school-aged children) and elderly people. Tree and weed pollen, human rhinovirus, and influenza virus had significant effects in school-age children. Tree pollen and influenza virus had significant effects in adults.

These results suggest that strategies to prevent AEs should consider patient age and multiple environmental factors. First, it is important to provide educational health messages regarding diurnal temperature range in pediatric and elderly people, groups that are especially vulnerable to temperature changes. Second, for children and adults who engage in a lot of outdoor activities, strategies to prevent AEs should consider seasonal variations of aeroallergens. Third, school-age children and adults who engage in community-based social activities should be alerted to the prevalence of respiratory virus infections, such as influenza virus and rhinovirus. Finally, because there is no completely safe level of air pollutants, more stringent regulations on industry and automobiles, and a more active notification system for high levels of air pollutants, may help to prevent AEs.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

Graphical Abstract