Abstract

Background and aims: Knowledge of how intrinsic capacity (IC) shape functional ability (FA) trajectories in later life remains unclear. We investigated the changes in IC and their impact on 5-years FA trajectories in the Chinese older population.

Methods: A total of 1640 older adults from the Rugao Longitudinal Ageing Study were included and analyzed. FA was assessed by The Lawton Instrumental Activities of Daily Living Scale (IADLs). We used cognition, psychology, locomotion, sensory capacity, and vitality to capture the multiple domains of IC according to the ICOPE method. The IC was derived retrospectively from variables collected before this was described by WHO.

Results: At baseline, a higher IC was associated with higher IADLs (β = 0.98, 95% CI 0.90, 1.06, P < 0.001). Individuals with declines in IC between wave1 and wave2 experienced a faster decline in IADLs over time (β = - 0.28, 95% CI - 0.40, - 0.16, P < 0.001) after considering covariates. One or more impairment IC scores at baseline strongly predicted death (HR = 1.20, 95% CI 1.11, 1.30, P < 0.001). In addition, according to the IC scores at baseline, we stratify IC in low, middle, and high, compared with those in the high IC score, those in the low were associated with a 2.56-fold (95% CI 1.64, 4.01, P < 0.001) higher risk of mortality, after adjustment for variables.

Conclusion: Changes in IC shape FA trajectories. IC impairment is associated with an increased risk of death. Assessing intrinsic capacity would facilitate early identification of older adults at high risk of adverse outcomes and prompt targeted interventions.