456 - Association between long-term PM2.5 and NO2 exposure and risk of myopia in children: national longitudinal cohort study

Publication Number: 456.3615

Ji Hyen Lee, Ewha Womans University Seoul Hospital, Seoul, Seoul-t'ukpyolsi, Republic of Korea; Hyemin Jang, Seoul National University, Seoul, Seoul-t'ukpyolsi, Republic of Korea

Background: Myopia is visual abnormality in which the resting eye focuses the image of a distant object at a point in front of the retina. Epidemiological studies have indicated a higher incidence of myopia in autoimmune diseases and an association with allergic inflammation. It is difficult to fully explain the pathogenesis of myopia solely through genetic and environmental factors.

Objective: We examined the association of long-term exposure to PM2.5 and NO2 with the risk of myopia.

Design/Methods: We utilized the National Health Insurance Service-National Sample Cohort spanning from 2002 to 2019, consisting of one million beneficiaries representative of the entire population in South Korea. The onset of myopia was the first hospital visit record with a primary diagnostic code based on the International Classification of Disease, 10th edition codes. For PM2.5 and NO2 exposure, we used a machine learning-based ensemble prediction model to achieve a high spatial resolution of 1 km2. We allocated the district-specific annual average concentration of PM2.5 and NO2 across all 229 districts in South Korea. We estimated the association between PM2.5 and NO2 and the onset of myopia using a time-varying Cox proportional hazard model adjusted for age, sex, socioeconomic status, region, and community level indicators.

Results: Our study included 36,440 individuals aged 18 and below at enrollment and followed until the first onset of myopia. The hazard ratios of development of myopia when annual PM2.5 concentration increased by 5μg/m³ were 1.05 (95% CI 1.03 to 1.08). The hazard ratios of development of myopia when annual No2 concentration increased by 5μg/m³ were 1.02 (95% CI 1.00 to 1.04). Based on the subgroup analysis, the HR for the age group 6-12 years was slightly higher than that for the 13-19 years age group (PM2.5: 1.06 (95% CI 1.03 to 1.09), NO2: 1.02 (95% CI 0.99 to 1.04). By gender, it was confirmed that males were more susceptible to myopia caused by PM2.5 and NO2 (Male PM2.5: 1.07 (95% CI 1.03 to 1.11), NO2: 1.04 (95% CI 1.01 to 1.07). There was no significant difference based on income levels. Regarding the level of urbanization of residence, urban areas were more susceptible to PM2.5, while rural areas were more vulnerable to NO2 (Urban PM2.5: 1.03 (95% CI 1.00 to 1.06), Rural NO2: 1.16 (95% CI 1.03 to1.31)).

Conclusion(s): Long-term exposure to PM2.5 and NO2 was associated with an increased incidence of myopia in children. These results indicate plausible mechanisms of air pollution and myopia, and our findings could provide important fundamental data for preventing myopia in children.

Fig 1. Concentration–response curves showing the association between long-term PM2.5 and No2 exposure and myopia


Table 1. Association between long-term PM2.5 and NO2 concentration and first hospital visit for Myopia


Table 2. Association between long-term PM2.5 and NO2 concentration and first hospital visit for Myopia by subgroups


Fig 1. Concentration–response curves showing the association between long-term PM2.5 and No2 exposure and myopia


Table 1. Association between long-term PM2.5 and NO2 concentration and first hospital visit for Myopia


Table 2. Association between long-term PM2.5 and NO2 concentration and first hospital visit for Myopia by subgroups