WEDNESDAY, Feb. 25, 2026 (HealthDay News) -- A causal relationship appears to exist between increased air pollution and outpatient visits for chronic rhinitis, according to a study published online Feb. 23 in The Laryngoscope.
Su Hwan Kim, from Gyeongsang National University in Jinju, South Korea, and colleagues examined the short-term causal relationship between air pollution and outpatient visits due to chronic rhinitis using National Health Insurance Service data collected between Jan. 1, 2014, and Dec. 31, 2017. The causal effects were estimated using a two-stage generalized method-of-moments Poisson regression model.
The analyses included 81,210,447 outpatient visits for chronic rhinitis. Significant positive associations were seen between air quality index (AQI) and outpatient visits on lag days 0, 3, 5, and 6 in an instrumental variable analysis, with the strongest effect seen at lag 0 (relative risk, 1.078). The most vulnerable individuals were those aged 10 to 19 years, showing significant relative risks across all lag days (relative risks, 1.039 to 1.161). The validity of the proposed instrumental variable approach was supported by analyses using negative control outcomes and exposures, suggesting a robust causal effect of air quality index on outpatient chronic rhinitis visits.
"This approach moves beyond simple associations and addresses confounding biases, thereby offering a more accurate assessment of the true impact of air pollution on chronic rhinitis," the authors write. "This study presents a methodological advancement in evaluating the impact of air pollution on outpatient health care utilization for chronic rhinitis."