Sarcopenic Obesity and Sex-Specific Functional Impairment in Older Adults: An Observational Case–Control Study

Background: Sarcopenic obesity (SO) is a clinically relevant but often under-recognized condition in older adults. This study examined whether obesity severity and body fat distribution are associated with physical capacity, functional autonomy and health-related quality of life in a sex-specific manner. Methods: In this observational case–control study with cross-sectional assessments, 45 older obese adults (OB; 27 men and 18 women) and 40 non-obese (NOB) comparison participants (18 men and 22 women), aged 65–85 years, underwent anthropometric assessment, bioelectrical impedance analysis, geometric body shape indexing, physical performance testing, autonomy assessment, physical activity evaluation and health-related quality-of-life assessment. SO was classified using a study-specific operational application of the ESPEN/EASO framework based on excess adiposity, impaired muscle function, and BIA-derived skeletal muscle mass adjusted for body mass. Results: Using this operational framework, all participants in the OB group were classified as presenting an SO phenotype. OB men showed substantially greater visceral adipose tissue mass than OB women (+106.5%, ES: 1.27, large, p < 0.001) and a higher A body shape index-associated relative risk (+27.9%, ES: 0.82, large, p < 0.001). Conversely, OB women showed more severe mobility impairment than OB men, with lower performance in the 8-Foot Up-and-Go (−22.9%, ES: 0.66, medium, p < 0.001) and 6-Min Walk test (−23.4%, ES: 0.64, medium, p < 0.001) and slightly lower basic autonomy. Health-related quality of life was significantly reduced only in OB men (−10.8%, ES: 1.07, large, p < 0.001) than NOB. Conclusions: In this clinical sample, an operational SO phenotype was identified among older OB adults and exhibited divergent sex-specific profiles. Men showed a predominantly geometric visceral risk phenotype and poorer perceived health status, whereas women showed more pronounced impairment in mobility and basic functional autonomy. These findings support sex-differentiated, multidisciplinary rehabilitation strategies in older adults with obesity.