In a multicenter retrospective cohort of 130,832 Chinese adolescents aged 8–17 screened between 2022 and 2024, every 1 kg/m² increase in BMI correlated with a −0.008 logMAR decline in uncorrected visual acuity and a +0.26 beats-per-minute rise in resting heart rate. The BMI–vision relationship was strongest in younger children (ages 8–11), weakened through mid-adolescence, and reversed at age 17. Girls showed stronger BMI–vision associations, while resting heart rate decreased with age and was marginally lower in boys—patterns shaped significantly by age–sex interactions.
The scale of this dataset lends statistical credibility to associations that smaller studies have suggested individually, but important caveats apply. This is an observational, retrospective design: it cannot establish causality between obesity, myopia, and cardiovascular load. The mechanisms linking adiposity to visual acuity remain speculative—proposed pathways include orbital adipose pressure, systemic inflammation, and insulin resistance affecting retinal development. The resting heart rate finding is more mechanistically grounded, as obesity increases cardiac output demand. Notably, the logMAR effect size per BMI unit is small and may not translate to clinically meaningful vision loss in individuals. The proposed policy implication—integrated, sex- and age-stratified screening for obesity, myopia, and cardiovascular risk simultaneously—is pragmatically appealing for public health systems. However, as a preprint not yet peer-reviewed, these findings and their interpretive framing warrant independent validation before influencing clinical guidelines.