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

Purpose: 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. Patients and Methods: 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. Results: Compared with individuals with lower BMI Q1 (less than 25 kg/m 2 ), 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/m 2 ) and 2.39 (95% CI: 1.37– 4.18) in Q3 (30.0 kg/m 2 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/m 2 , 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/m 2 , the association lost its significance (OR = 1.063 [95% Cl: 0.964– 1.171], p = 0.219). Conclusion: 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/m 2 , after which an increase in BMI was no longer associated with an increased risk of myopia. Keywords: myopia, body mass index, cross-sectional, schoolchildren, logistic regression