Inverse L-Shaped Association Between Body Mass Index and Myopia in Chinese Schoolchildren: A Pilot Study

The prevalence of obesity and myopia in young people is increasing worldwide; however, the association between body mass index (BMI) and myopia remains controversial. This study aimed to assess the association between BMI and myopia in Chinese schoolchildren.

In this study, the open data for analysis were obtained from DATADRYAD website (www.datadryad.org). A total of 3658 children were enrolled in this study. Logistic regression model was used to analyze the relationship between BMI and myopia.

Compared with individuals with lower BMI Q1 (less than 25 kg/m²), the adjusted odds ratios (ORs) for BMI and myopia were 2.15 (95% confidence interval [CI]: 1.62-2.86) in Q2 (25.0-29.9 kg/m²) and 2.39 (95% CI: 1.37-4.18) in Q3 (30.0 kg/m² or more). Moreover, the association between BMI and myopia exhibited an inverted L-shaped curve (nonlinear; p < 0.001). When the BMI was <25 kg/m², an increased BMI was significantly associated with a higher risk of myopia (OR = 1.244 [95% CI: 1.211-1.277], p < 0.001). However, when the BMI was ≥25 kg/m², the association lost its significance (OR = 1.063 [95% Cl: 0.964-1.171], p = 0.219).

This study found an inverted L-shaped association between BMI and myopia in Chinese schoolchildren. A higher BMI was associated with a higher risk of myopia reaching 25 kg/m², after which an increase in BMI was no longer associated with an increased risk of myopia.