Diabetes-Related Balance Impairment in the Aging Population: A Combined NHANES and Mendelian Randomization Study

Introduction: Diabetes mellitus contributes to motor control impairments that can compromise balance and increase fall risk, particularly in older adults. Given that both the prevalence of aging and diabetes is increasing globally, understanding this relationship is vital for targeted fall prevention. This study examined the association between diabetes status and balance performance in older adults and assessed potential causal relationships using Mendelian randomization. Methods: We analyzed 1,218 adults aged 60+ years from the 2021–2023 National Health and Nutrition Examination Survey (NHANES). Participants were classified as nondiabetic (n = 248), prediabetic (n = 690), or diabetic (n = 280) on the basis of fasting glucose and HbA1c. Balance was evaluated via the modified Romberg test. Associations were examined via ordinal logistic regression, and causality was assessed via Mendelian randomization with diabetes-related genetic instruments. Results: In fully adjusted models, diabetes was strongly associated with impaired balance (β = -0.88; 95% CI: -1.33 to -0.44; p < 0.001). Prediabetes also demonstrated a significant association with balance impairment (β = -0.53; 95% CI: -0.85 to -0.22; p < 0.001). Mendelian randomization provided evidence that genetically predicted diabetes was associated with increased fall risk (OR = 4.75; 95% CI: 1.48–15.24; p = 0.009). Conclusions: Observational analyses link diabetes and prediabetes to poorer balance performance, and genetic evidence supports an association between diabetes liability and increased fall risk.