Abstract
BackgroundLate-onset asthma (onset > 12 years) is pathologically distinct from early-onset asthma. The mechanism of air pollution is not a classic allergic inflammation and could have differential effect on late-onset and early-onset asthma. However, there is little known about the association of onset-age phenotype and air pollution. In this population-based study, we aimed to determine the association of asthma severity outcomes and air pollution regarding age at onset of asthma.MethodsIn 2004, we conducted a cross-sectional questionnaire survey about respiratory health among schoolchildren’s parents randomly selected from 94 of 816 elementary and middle schools in southern Taiwan. Participants ever having typical asthma symptoms were enrolled. We used kriging method to estimate individual exposure to ambient air pollution in the preceding year before the year of asthma severity survey. Ordered logistic regression was used to determine the association of exposure and asthma severity scores. Age at asthma onset of 12 years was used as a cut-off to define early- or late-onset asthma.ResultsThe study surveyed 35,682 participants. Data from 23,551 participants remained satisfactory with a response rate of 66 %. Among 20,508 participants aged 26–50 years, 703 questionnaire-determined asthmatics were identified and included for analysis. Using the median of PM10 (66 μg/m3) as a cut-off, those exposed to higher PM10 were more likely to have higher severity scores (OR = 1.74; 95 % CI, 1.13 – 2.70) only for asthmatics with asthma onset at > 12 years.ConclusionsIn adulthood, exposure to PM10 has a greater effect on late-onset asthma than early-onset asthma and deserves greater attention among ambient air pollutants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-016-0218-0) contains supplementary material, which is available to authorized users.
Highlights
IntroductionLate-onset asthma (onset > 12 years) is pathologically distinct from early-onset asthma
Late-onset asthma is pathologically distinct from early-onset asthma
As chronic residential traffic pollution was associated with eosinophilic airway inflammation in older asthmatics [19], we hypothesized that chronic exposure to air pollution has differential effect between early-onset and late-onset asthma
Summary
Late-onset asthma (onset > 12 years) is pathologically distinct from early-onset asthma. The mechanism of air pollution is not a classic allergic inflammation and could have differential effect on late-onset and early-onset asthma. Wu et al BMC Pulmonary Medicine (2016) 16:54 guidelines and Global Initiative for Asthma guidelines, employ the use of rescue short-acting β2-agonist (SABA) and other medications to maintain control as the determinants of asthma severity [11, 12]. As chronic residential traffic pollution was associated with eosinophilic airway inflammation in older asthmatics [19], we hypothesized that chronic exposure to air pollution has differential effect between early-onset (onset ≤ 12 years) and late-onset asthma (onset > 12 years). We tested the hypothesis in a population-based study by using kriging method for better classification of personal ambient air pollution exposure
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