The Relationship Between Load-Capacity Index and Common Geriatric Syndromes

Introduction:The body mass index (BMI) does not accurately reflect changes in fat and muscle with age.The metabolic load-capacity framework identifies fat as "load" and muscle as "capacity"; this is measured by the load-capacity index (LCI), defined as the fat-massto-fat-free-mass ratio (FM/FFM).This study examined the relationship between LCI and health outcomes in older adults across obesity levels defined by BMI.Methods: This study included adults aged 65 years and older who visited the Geriatric Outpatient Clinic from January 2024 to April 2025.A total of 113 participants were divided into two groups based on the number of geriatric syndromes: low (0-2 syndromes; 55 participants) and high (3 or more syndromes; 58 participants).The study used statistical tests to compare the groups and to examine the association between LCI and the frailty index, the SARC-F score, and the total number of geriatric syndromes. Results:The high syndrome burden group demonstrated significantly worse physical performance, higher LCI, greater FM, lower lean body mass, poorer nutritional status, reduced functional independence, and higher rates of depression, polypharmacy, falls, urinary incontinence, and obesity compared with the low burden group, whereas age, sex, walking speed, and cognitive status did not differ between groups.In the obesity subgroup, objective performance measures and functional independence were comparable to those of the non-obese group, yet frailty, sarcopenia risk, syndrome burden, and LCI were significantly elevated, underscoring the limitations of BMI alone.LCI showed significant, moderate positive correlations with the frailty index, the SARC-F score, and the total number of geriatric syndromes.Conclusion: Elevated LCI values were significantly associated with increased frailty, higher SARC-F scores, and a greater prevalence of geriatric syndromes.This finding supports the use of FM/FFM as a practical, biologically meaningful adjunct to CGA for screening and risk stratification in older adults.