Differential Effects of Green Space Typologies on Congenital Anomalies: Data from the Korean National Health Insurance Service (2008-2013)

Abstract

Background/Objectives: Urban green space has been increasingly recognized as a determinant of maternal and child health. This study investigated the association between prenatal exposure to different types of green space and the risk of congenital anomalies in South Korea. Methods: We analyzed data from the National Health Insurance Service (N = 142,422). Green space exposure was measured at the area level and categorized into grassland and forest; statistical analysis was performed using generalized estimating equations and generalized additive models to analyze the associations. Additionally, subgroup and sensitivity analyses were performed. Results: GEE analysis showed that a 10% increase in the proportion of grassland in a residential district was associated with a reduced risk of nervous system (adjusted odds ratio [aOR]: 0.77, 95% confidence interval [CI]: 0.63-0.94) and genitourinary system anomalies (aOR: 0.83, 95% CI: 0.71-0.97). The subgroup analysis results showed significance only for male infants, but the difference between the sexes was not significant. In the quartile-based analysis, we found a slightly significant p-value for trend for the effect of forests on digestive system anomalies, but the trend was toward increasing risk. In a sensitivity analysis with different exposure classifications, the overall and nervous system anomalies in built green space showed that the risk decreased as green space increased compared to that in the lowest quartile. Conclusions: Our results highlight the importance of spatial environmental factors during pregnancy and suggest that different types of green spaces differentially impact the offspring's early health outcomes. This study suggests the need for built environment planning as part of preventive maternal and child health strategies.

Keywords: built environment; case–control study design; congenital anomalies; green space.

Figure 1

Land cover map for different vegetation types. (a) Spatial distribution of different types of urban green spaces in Seoul, categorized into broad-leaved forest, coniferous forest, mixed forest, natural grassland, and built grassland, based on vegetation structure. (b) A detailed view of green space type overlaid on a high-resolution aerial map.

Figure 2

Dose–response relationship of each grassland green space with (a) nervous system and (b) genitourinary system anomalies in the full adjusted multivariable GAM. Shaded areas represent 95% confidence intervals. Models were adjusted for sex, birth year, season of birth, income, temperature, population density, unmet medical need rate, OB/GYN clinics, PM_2.5, NO₂, CO, SO₂, and O₃. OB/GYN, obstetrics and gynecology; PM_2.5, airborne particles with an aerodynamic diameter ≤ 2.5 μm; NO₂, nitrogen dioxide; CO, carbon monoxide; SO₂, sulfur dioxide; O₃, ozone.