Author(s): PARK, J., YUN, S., LEE, S., HAN, Y., CHOI, Y., KIM, Y., Institution: SEOUL NATIONAL UNIVERSITY, Country: KOREA, SOUTH, Abstract-ID: 1078

INTRODUCTION:
Low handgrip strength (HGS), defined as possible sarcopenia by the Asian Working Group for Sarcopenia (AWGS) 2025, is a robust predictor of premature mortality. While physical activity may mitigate this risk, existing evidence often relies on total physical activity without isolating the domain, and the minimum effective dose of leisure-time physical activity (LTPA) required to offset the risk associated with possible sarcopenia remains unclear. This study aimed to examine the independent and joint association of LTPA and possible sarcopenia with all-cause mortality among Koreans aged >= 50.
METHODS:
This prospective cohort study included 12,741 participants (mean age 61.9 years; 51.4% female) from the Korea National Health and Nutrition Examination Survey 2014-2018. Possible sarcopenia was defined by the AWGS 2025 sex- and age-specific cutoffs. LTPA was assessed via self-reported questionnaires and calculated as metabolic equivalent of task (MET) values per week. LTPA was categorised as inactive (0), insufficient (1-599), and sufficient (>=600) for the independent analysis to evaluate the benefits of sub-optimal activity. For the joint analysis, it was dichotomised as inactive (0) vs active (>0) to examine the benefits of feasible behavioural targets. Cox proportional hazards models estimated hazard ratios (HR) for all-cause mortality risk, and non-linear dose-response relationships were assessed via restricted cubic splines (RCS). Sensitivity analysis excluding deaths within the first year of follow-up was performed to minimise reverse causality. All models were adjusted for sociodemographic factors, chronic conditions, health behaviours, and nutritional status.
RESULTS:
The mean follow-up period was 6.2 years (925 death). RCS analysis revealed inverse non-linear associations of HGS and LTPA with mortality, having steep risk decline upon engaging in any LTPA, with plateauing at low activity levels. Independent of LTPA, the normal group was associated with lower mortality (HR 0.64; 95% CI 0.53-0.76) than the possible sarcopenia. For LTPA, the insufficient LTPA (HR 0.50; 95% CI 0.33-0.76) showed a risk reduction comparable to the sufficient LTPA (HR 0.61; 95% CI 0.43-0.87) compared to inactivity. In the joint analysis, the possible sarcopenia and active group (HR 0.55; 95% CI 0.34-0.89) exhibited HR similar to the normal and inactive group (HR 0.63; 95% CI 0.53-0.76). The lowest risk was observed in the normal and active group (HR 0.36; 95% CI 0.25-0.52), remaining robust in the sensitivity analysis.
CONCLUSION:
Engagement in LTPA, even at levels below standard recommendations, effectively offsets the mortality risk associated with possible sarcopenia. This study indicates that initiating minimal LTPA allows possible sarcopenic individuals to achieve survival probabilities comparable to their inactive healthy peers. Therefore, public health strategies should highlight minimal LTPA as a viable and potent intervention target for sarcopenia management under the AWGS 2025 framework.