The effect of the interaction between intrinsic capacity and social support on the trajectories of activities of daily living in older adults

•This study is the first longitudinal study of the interaction among intrinsic capacity, social participation and family support on the trajectory of the daily activity ability of old people, in line with the development trend of active and healthy aging proposed by the WHO. The empirical results show that the interaction between intrinsic capacity and the environment can promote functional performance.•The latent growth curve model (LGCM) was used to examine the effect of the interaction between social support and intrinsic capacity on the ability of elderly people to perform activities of daily living.•The ADL score of the elderly participants showed a significant downward trend with time over 4 years. In the elderly population with high intrinsic capacity, the daily activity ability of individuals with low levels of social participation decreased significantly over time. In the elderly group with low intrinsic capacity, the daily activity ability of individuals with low levels of social participation and high levels of life care decreased significantly over time.•It is necessary to develop individualized interventions for older people with different characteristics. Attention should particularly be given to old people with impaired intrinsic capacity to improve their social participation, encourage them to actively participate in social activities, and call on their children to give older people more emotional comfort and material security in their lives. This can optimize older people's ability to perform daily activities and promote healthy aging. This study explored the effect of the interaction between intrinsic capacity and social support on the activities of daily living in the older adults. A total of 3,124 older adults participated in the study. Data on the assessment of intrinsic capacity as well as activities of daily living (ADL) and social support were collected. The latent growth curve model (LGCM) was used to examine the effect of the interaction between social support and intrinsic capacity on the activities of daily living in the older adults. A total of 3,730 older adults were included at baseline, and 3,124 older adults completed the 4-year follow-up. The ADL score of the older adults showed a significant downward trend with time over 4 years (β=-0.115, P