The impact of BMI on myopia incidence in Chinese children

PURPOSE: This research explored the relationship between body mass index (BMI) and myopia in China. DESIGN: Retrospective cohort study. METHODS: This retrospective study included 9054 participants from Bengbu, China, from the years 2022 to 2024. The data included age, gender, spherical equivalent (SE), weight, height, body mass index (BMI), and the changes in these parameters measured between 2022 and 2024. Regression analysis was used to analyze the relationships between weight, height, BMI, and SE. RESULTS: The findings showed that the incidence of moderate and high myopia rises with age. Specifically, the measured prevalence rates across different years were: moderate myopia - 10.1% (2022), 10.7% (2023), 20.6% (2024); high myopia - 2.3% (2022), 2.4% (2023), 4.1% (2024). As height, weight, and BMI increase, the ratio of moderate and high myopia rises in 2022 to 2024 (P < 0.001). Participants with a height greater than 150 cm, a weight greater than 60 kg, and a BMI greater than 25.0 experienced a 12%, 32%, and 13% increased risk of myopia, respectively (OR 1.12; p = 0.013, OR 1.32; p = 0.028, OR 1.13; p = 0.021). The most significant factors negatively associated with SE were age (B = -0.303 in 2022, -0.312 in 2023, -0.321 in 2024, P < 0.001) and BMI (B = -0.204 in 2022, -0.194 in 2023, -0.291 in 2024, P < 0.001). The change in SE is associated with changes in height and BMI, but not with change in weight (P > 0.05). CONCLUSIONS: The incidence of myopia and the severity of the condition in this group of Chinese children did increase annually between 2022 and 2024. Weight, height, and BMI are associated with the occurrence of myopia. Changes in height and BMI correlate with alterations in SE.