Association between ozone and emergency department visits in people with disabilities in South Korea: a nationwide case-crossover study

Vollständiger Abstract

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Abstract Background Ozone is known to have harmful health impacts, and its concentration is projected to rise with climate change; however, little is known about how ozone impacts the health of people with disabilities and its interaction with temperature. We aimed to estimate the association between ozone exposure and emergency department (ED) visits, stratified by disability status and type. Methods ED visit data spanning 2015–19 and 2022–23 were collected from the Korean National Health Insurance Service. We included the 3-day moving average (the same day, 1 day prior, and 2 days prior; lag 0–2) ozone concentration at the 8-hour maximum and adjusted for daily mean temperature and national holidays. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the association between ozone concentration and natural-cause ED visits. Furthermore, an interaction term between temperature strata and ozone was included to assess potential effect modification across temperature value. Results Overall, 3 484 877 ED visits were recorded. An interquartile range (∼22 ppb) increase in daily 8-hour maximum ozone (lag 0–2) was associated with a 1.94% increase [95% confidence interval (CI): 1.64–2.25] and a 1.93% increase (95% CI: 1.62–2.25) in ED visits during the warm season (April–September) and the entire year (January–December), respectively, among persons with disabilities. These estimates were higher than those observed among persons without disabilities [1.36% (95% CI: 0.92–1.80) and 1.42% (95% CI: 1.03–1.82) during the warm season and the entire year, respectively]. Greater risks were observed in brain lesion disorders, developmental and mental disabilities, ED visits due to respiratory diseases during June, and on days with high temperatures. Conclusions These findings underscore the importance of tailoring strategies to specific disability types and early-season public health interventions—beginning in April or May—incorporating both ozone levels and daily temperature to effectively mitigate the heightened risks identified in this population.