Association of social frailty with objectively measured physical activity in Japanese community-dwelling older adults: A Ritsumeikan frailty study (RiFS)

ABSTRACT Background: Social frailty (SF), characterized by reduced social roles and interactions, is an important factor influencing health among older adults. However, its relationship with objectively measured physical activity (PA) remains unclear. Objectives: This study aimed to examine the associations between SF—including its individual components—and objectively measured PA in Japanese community-dwelling older adults. Methods: In this cross-sectional study, 103 older adults aged ≥65 years were analyzed. SF was assessed using the Makizako scale. PA was objectively measured using a tri-axial accelerometer over four days, evaluating step counts, sedentary behavior (SB), light-intensity PA (LPA), moderate-to-vigorous PA (MVPA), and types of PA (locomotive vs. non-locomotive). Results: Older adults with SF showed significantly lower total activity, step counts, and LPA, along with higher SB. Both locomotive and non-locomotive LPA were negatively associated with SF, while no significant association was found with MVPA. Among the individual components of SF, “going out less frequently” was negatively linked to various intensity and type of PA. Similarly, those who did not feel helpful exhibited lower levels of locomotive PA. Conclusion: The results suggest that SF and its components are associated with PA—specifically total activity, step counts, LPA, SB, locomotive PA, locomotive LPA, non-locomotive PA, and non-locomotive LPA—among Japanese community-dwelling older adults.