Association between exposure to particulate matter and school absences in Korean asthmatic adolescents

Background

Because particulate matter (PM) and asthma are closely related, the prevalence of school absence among adolescents with asthma can be affected by the concentration of PM. We aimed to investigate the relationship between school absences due to asthma and the total number of days that the PM concentration exceeded the standard.

Methods

We used the data from the 16th Korea Youth Risk Behavior Survey and the PM levels of 17 metropolitan cities and provinces gathered from the AirKorea. Information on the characteristics of asthmatic adolescents and the prevalence of school absence was obtained using a questionnaire, while the PM levels based on the total number of days with poor and very poor PM grades were collected from the AirKorea website. Both χ² test and logistic regression analysis were performed using the weights presented in the original dataset.

Results

In the case of particulate matter of 10 microns in diameter or smaller (PM₁₀), the odds ratio (OR) after adjusting for confounders (sex, school year, body mass index, smoking history, diagnosis of allergic rhinitis, diagnosis of atopic dermatitis and city size) was 1.07 (95% confidence interval [CI]: 1.01–1.13) for absents due to asthma when the total days of poor and very poor grades of PM₁₀ (81 μg/m³ or higher) increased by 1 day. In the analysis of particulate matter of 2.5 microns in diameter or smaller (PM_2.5), the OR after adjusting for confounders was 1.01 (95% CI: 1.00–1.03) for absents due to asthma when the total number of days with poor and very poor PM_2.5 grades (36 μg/m³ or higher) increased by 1 day.

Conclusions

A significant association was observed between the total number of days of poor and very poor PM₁₀ and PM_2.5 grades and school absence due to asthma; PM can cause asthma exacerbation and affect the academic life.

The association of nasal patency with small airway resistance in children with allergic and nonallergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is immunologically and morphologically related to disorders in the lower airway. We investigated the relationship between the anatomy of the intranasal cavity and small airway resistance in subjects with nonallergic rhinitis (NAR).

METHODS

We enrolled 226 children who were 7 years old and participated in the Seongnam Atopy Project 2016. We evaluated nasal patency using acoustic rhinometry to measure the volume of the nasal cavity at 0-5 cm, and measured lung function of the lower airway using an impulse oscillometry system (IOS) and spirometry. We also performed skin prick tests for 18 aero-allergens, and measured blood total eosinophil counts (TEC) and rhinitis symptom scores for the previous month using a visual analog scale (VAS, range: 0-10).

RESULTS

We examined 226 children, 71 (31.7%) with AR, and 62 (27.7%) with NAR. Nasal patency in children with AR (median: 8.28 mm³ , IQR: 7.07-9.83) was lower than that of healthy children (median: 9.3 mm³ , IQR: 7.69-10.64, P = 0.011). Multivariate regression analysis showed that nasal patency was inversely associated with IOS resistance at 5 Hz after adjustment for compounding factors (B = -0.005, SE = 0.0032, P = 0.041). Analysis of NAR subjects, according to quartiles of nasal patency and quartiles of small airway resistance (Rrs5), indicated that nasal patency decreased as Rrs5 increased (linear trend: P = 0.020).

CONCLUSION

Nasal symptoms and TEC negatively correlated with nasal patency. Children with AR and NAR who had poor nasal patency had increased small airway resistance.