National trends in allergic rhinitis and chronic rhinosinusitis and COVID-19 pandemic related factors in South Korea, from 1998 to 2021

Introduction: Existing studies provide insights into the prevalence and environmental factors associated with allergic rhinitis (AR) and chronic rhinosinusitis (CRS) globally. However, limitations still persist in these studies, particularly regarding cohort sizes and the duration of follow-up periods, indicating a need for more comprehensive and long-term research in these fields. Our study aimed to investigate the prevalence, long-term trends, and underlying factors of these conditions in the general population of adult participants (≥19 years) in Korea. Method: We analyzed data from adult participants (≥19 years) from the Korea National Health and Nutrition Examination Survey (KNHANES) study to determine the prevalence of AR and CRS from 1998 to 2021. To analyze prevalence trends before and during the COVID-19 pandemic, we employed a weighted linear regression model and obtained β-coefficients with 95% confidence intervals (CI). Results: Between 1998 and 2021, over a span of 24 years, the comprehensive KNHANES study included 146,264 adult participants (mean age: 47.80 years, standard deviation: 16.49 years; 66,177, 49.3% men). The prevalence of AR and CRS increased from 1998 to 2021, with AR prevalence rising from 5.84% (95% CI, 5.57–6.10) in 1998–2005 to 8.99% (8.09–9.91) in 2021 and CRS from 1.84% (1.70–1.97) in 1998–2005 to 3.70% (3.18–4.23) in 2021. However, the increasing trend has slowed down during the COVID-19 pandemic era. Conclusions: The significance of continuous monitoring and focused interventions for AR and CRS is underscored by this study. The observed deceleration in the rising prevalence of AR and CRS during the pandemic indicates the possibility of beneficial impacts from lifestyle modifications triggered by the pandemic. These findings call for additional research to explore potential protective effects in greater depth.