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

Background: 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.

Method: 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.

Results: 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.

Conclusion: 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.