Associations between Body Mass Index and Visual Impairment of School Students in Central China

Body Mass Index (BMI) is a risk indicator for some eye diseases. However, the association between BMI and Visual Impairment (VI) was not quite certain in Chinese students. Our aim was to assess the relationship between BMI and VI with a cross-sectional study. A total of 3771 students aged 6-21 years, including 729 with VI, were sampled from 24 schools in Huangpi District of central China to participate in the study. A multistage stratified cluster random sampling was adopted. Each of the students answered a questionnaire and had physical and eye examinations. The association between BMI and VI was examined with logistic regression and threshold effect analysis. The prevalence of VI was 19.33% (729/3771). Compared to normal and underweight, overweight/obese students showed a stronger relation with VI in age- and sex-adjusted (Odds Ratio (OR) = 16.16, 95% Confidence Interval (CI): 12.37-21.09, p < 0.001) and multivariable models (OR = 8.32, 95% CI: 6.13-11.30, p < 0.001). There was a nonlinear dose-response relation between levels of BMI and the prevalence of VI (p < 0.001). A high level of BMI (≥19.81 kg/m²) was associated with a higher VI prevalence (adjusted OR = 1.20, 95% CI: 1.15-1.25, p < 0.001). In conclusion, the study demonstrated BMI levels were significantly associated with the prevalence of VI.