Abstract
Objective
We examined whether school physical-fitness performance was associated with screening-defined current myopia in primary grade 1 and junior middle grade 1 students. We also explored item-level fitness profiles in relation to current myopia status.
Methods
We analyzed routine health-screening records collected in 2025 from three schools in Xicheng District, Beijing. Screening-defined current myopia required unaided visual acuity
Results
The analysis included 1,296 students: 642 in primary grade 1 and 654 in junior middle grade 1. Current myopia by the screening definition was identified in 496 students (38.3%), with prevalence of 6.7 and 69.3% in the two grade-stage groups, respectively. In the original adjusted models, students who failed the fitness standard had a higher myopia prevalence than those rated excellent (PR = 1.95, 95% CI: 1.36–2.79). A 1-SD lower motor-fitness score was also associated with higher prevalence (PR = 1.14, 95% CI: 1.03–1.26). After accounting for school and within-class clustering, the fail-versus-excellent estimate remained evident (PR = 1.95, 95% CI: 1.13–3.38); so did the estimate for lower motor fitness in primary grade 1 (PR = 2.05, 95% CI: 1.13–3.69). The remaining estimates pointed in similar directions but were less precise. Internal machine-learning performance was moderate, and item attributions varied by model and grade stage.
Conclusion
Failing the official fitness standard and having lower motor fitness were associated with screening-defined current myopia in this cross-sectional sample. The clearest association was found in primary grade 1. These results cannot establish which condition came first and may reflect non-cycloplegic misclassification, reverse causation, or shared behavioral, familial, developmental, educational, and environmental influences. Fitness measures are not ready for use in myopia prediction or screening.