Association between residential greenness and allergic diseases among adolescents in South Korea: A nationwide representative study

Residential greenness is an important environmental factor potentially influencing the development of allergic diseases in adolescents; however, its impact remains understudied in South Korea. This study aimed to examine the association between residential greenness and allergic disease prevalence using nationally representative data. We analyzed data from 1,130,598 adolescents (7-12th grade) participating in the Korean Youth Risk Behavior Web-based Survey (2007-2024). Residential greenness was estimated using the normalized difference vegetation index (NDVI) derived from satellite imagery based on GPS coordinates. Logistic regression models assessed associations between NDVI and physician-diagnosed allergic rhinitis (AR), atopic dermatitis (AD), and asthma, with subgroup analyses conducted by sex, school grade, household income level, and sufficiency of fatigue recovery. Among 1,130,598 adolescents (51.27% boys), 525,979 (46.52%) participants reported allergic diseases: 363,167 (32.12%) with AR, 250,462 (22.15%) with AD, and 88,584 (7.84%) with asthma. Higher residential greenness was associated with lower adjusted odds ratios of AR (0.83 95% CI, 0.78-0.89), AD (0.75 0.70-0.80), and asthma (0.45 0.41-0.50), with the strongest inverse association observed for asthma. The protective association of greenness was stronger in middle school students compared to high school students and in the higher-income group compared to the low-income group. Residential greenness was associated with a reduced prevalence of allergic diseases among Korean adolescents, with stronger protective associations observed among middle school students and those from higher-income households. These findings highlight the need to improve equitable access to green spaces for all adolescents.