A repeated measures multilevel model study on the association between visual acuity and body mass index in preschool children
Shang Aiping, Chen Jinghua, Zhuo Xiaoyu, et al.
1. Department of Child Health Care, Shandan County Maternal and Child Health Hospital, Zhangye, Gansu 734100, China; 2. The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, China; 3. Health Management Center, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, China
Objective To evaluate the dynamic changes in visual acuity and body mass index (BMI) over three years of repeated measurements among children aged 3-5 years in Shandan County, Gansu Province. Methods A cluster sampling method was adopted to select 1,507 preschool children aged 3-5 years who underwent kindergarten physical examinations at the Shandan County Maternal and Child Health Hospital from July 2022 to October 2024 as the study subjects. According to the BMI percentile method, the subjects
were divided into the emaciation group (n=125), normal group (n=1,240), overweight group (n=106), and
obesity group (n=36). Data including gender, age, height, body weight, and visual acuity were recorded
consecutively for 3 years from 2022 to 2024. Statistical analysis was performed using One-way analysis
of variance, and a multilevel model for multivariate repeated measurement data was used for data analysis. Results The results of the One-way analysis of variance showed that there were no statistically significant differences among the four groups at baseline in age, left-eye visual acuity, or right-eye visual acuity (all P>0.05). Multilevel analysis of repeated-measures multivariable data demonstrated that, after adjustment for age, girls in the overweight group had significantly better baseline visual acuity in both eyes than those in the normal group (left eye: β=0.074, P=0.022; right eye: β=0.070, P=0.029). The interaction between left-eye visual acuity and measurement time was statistically significant for girls in emaciation group (β=-0.038, P=0.009), indicating that left-eye visual acuity of girls declined more rapidly over time in emaciation groupgirls than that in normal group. The interaction terms between right-eye visual acuity and measurement time were also statistically significant for girls in overweight group (β=-0.037, P=0.011), suggesting a faster decline in right-eye visual acuity over time compared with the normal group. Among boys, no statistically significant differences were observed between the emaciation or overweight groups and the normal group ineither baseline binocular visual acuity or longitudinal changes over time (all P>0.05). However, compared with the normal group, the interaction terms between both eyes and measurement time were statistically significant for boys in obesity group (left eye: β=-0.039, P=0.030; right eye: β=-0.035, P=0.040), indicating a significantly faster decline in visual acuity over time compared with the normal group. In addition, age had a significant effect on visual acuity in both eyes among children (all P<0.001). Conclusion Visual developmentin children exhibited both age and gender dependent characteristics, suggesting that vision monitoring should be initiated as early as possible, with particular attention to girls. Visual acuity declined more rapidly over time in overweight and obesity children, highlighting the need for greater attention to visual deterioration in these groups and for targeted preventive measures. Emaciation girls also constituted a high-risk group for visual decline. Both undernutrition and overnutrition may exert persistent adverse effects on visual development. Comprehensive interventions integrating body weight management and vision protection may effectively delay the onset of myopia in preschool children and reduce myopia progression.
2026, Vol. 14 
