Supplementary file 1_Independent and joint associations of intrinsic capacity and frailty index with incident disability and all-cause mortality among older Chinese adults.docx

All-cause mortality was ascertained during follow-up. Multivariable logistic regression and Cox proportional hazards models were applied, together with joint association and incremental predictive analyses.</p>Results<p>In fully adjusted models, higher IC was independently associated with lower odds of incident disability [odds ratio (OR) = 0.79, 95% confidence interval (CI): 0.74–0.84], whereas higher FI was associated with greater odds of disability (OR per 0.1 increase = 1.93, 95% CI: 1.67–2.23).

Similarly, higher IC was associated with reduced risk of all-cause mortality [hazard ratio (HR) = 0.84, 95% CI: 0.82–0.85], whereas higher FI was associated with increased mortality risk (HR per 0.1 increase = 1.25, 95% CI: 1.19–1.31). After mutual adjustment, both IC and FI remained significantly associated with incident disability, whereas only IC remained significantly associated with all-cause mortality. Participants with concomitantly lower IC and higher FI exhibited the greatest risks of both disability (OR = 4.31, 95% CI: 2.65–7.04) and mortality (HR = 2.66, 95% CI: 2.32–3.04).</p>Conclusion<p>Both IC and FI were significantly associated with incident disability and all-cause mortality among older Chinese adults.

The combination of IC and FI identified distinct profiles of functional and mortality risk, while IC showed a stronger association with mortality than FI.</p>