Combined Social Frailty and Life-Space Activities Associated with Risk of Disability: A Prospective Cohort Study.

Objectives: To examine the association between social frailty and life-space activities, and determine whether a combined status of life-space activities and social frailty is associated with risk of disability among older adults.

Design: A prospective cohort study.

Setting and participants: The participants were 8,301 older adults (mean age 72.9 ± 5.6 years, women [53.3%]) from a community setting.

Methods: Life-space activities were evaluated using the Active Mobility Index (AMI) to assess activities in each life-space (distance from the respondent's home: up to 1 km, 1-10 km, or greater than 10 km) during the past 1 month. Activities were also assessed according to physical or social activity. Social frailty and characteristics were measured at the baseline. Incident disability was assessed according to long term care insurance.

Results: The lowest scoring group was based on the quartile in each of the AMI scores (Q1), with reference to the highest scoring group, which had a higher odds ratios for social frailty (AMI total score Q1: OR 4.32, 95% CI 3.43-5.45, AMI physical score Q1: 2.19, 95% CI 1.79-2.69, AMI social score Q1: 5.04, 95% CI 3.94-6.44). During the follow-up (mean 23.5 months), 330 participants had incident disability. Incident disability was associated with social frailty. Combined status of social frailty and low AMI increased the risk of disability (HR 2.15, 95% CI 1.52-3.03), with reference to non-frailty and higher AMI scores.

Conclusions and implications: Social frailty or reduced activity in life-space assessment were identified as risk factors for incident disability. To decrease the risk of disability, the development of an intervention program to enhance activities and cope with social frailty is required.