Consensus-Defined Sarcopenic Obesity and a Related Dynapenic Obesity Phenotype in Relation to Early Cognitive...

Previous studies examining sarcopenic obesity in relation to cognitive function have utilized heterogeneous operational definitions. Some studies have evaluated low muscle strength combined with obesity, more appropriately described as dynapenic obesity, under the broader term sarcopenic obesity. We examined the associations of consensus-defined sarcopenic obesity and a related strength-based obesity phenotype with global and domain-specific cognitive function in older adults and evaluated the robustness of these associations across alternative adiposity definitions.

This prospective cohort study (2015-2019) included non-demented older adults from the Taiwan Initiative for Geriatric Epidemiological Research. Participants underwent cognitive assessments at baseline and at the 2-year follow-up. Handgrip strength was measured using a dynamometer, and total muscle mass was measured by bioelectrical impedance analysis. Obesity was defined primarily as a body mass index ≥ 27 kg/m². Sarcopenic obesity was defined as the coexistence of low muscle mass, low muscle strength and obesity, whereas dynapenic obesity was defined as low muscle strength and obesity. Multivariable-adjusted generalized linear mixed models were used to examine the associations of sarcopenic obesity and a related dynapenic obesity phenotype with cognitive function across repeated measurements and over time.

At baseline, 366 older adults aged ≥ 69 years (54.6% women, mean ± standard deviation [SD] = 75.7 ± 4.8 years) were included. All 16 participants with dynapenic obesity also met the criteria for sarcopenic obesity. Sarcopenic obesity was associated with poor global cognition (MoCA-T: $\hat{\beta }$  = -0.96; 95% confidence interval [CI] -1.80 to -0.13), memory (immediate free recall: $\hat{\beta }$  = -0.38; 95% CI, -0.72 to -0.04) and attention performance (Trail Making Test A: $\hat{\beta }$  = -0.43; 95% CI, -0.73 to -0.12). Dynapenic obesity was associated with poor global cognition (MoCA-T: $\hat{\beta }$  = -1.15; 95% CI, -1.99 to -0.30), memory (immediate free recall: $\hat{\beta }$  = -0.43; 95% CI, -0.77 to -0.09) and attention performance (Trail Making Test A: $\hat{\beta }$  = -0.44; 95% CI, -0.75 to -0.14). The associations of sarcopenic obesity and dynapenic obesity with global cognition and attention performance remained evident among women and apolipoprotein E (APOE) ε4 non-carriers.

Sarcopenic obesity and a related dynapenic obesity phenotype were associated with poor global and domain-specific cognitive function in non-demented older adults. Muscle strength and obesity measures may facilitate early identification of these phenotypes and help identify individuals at increased risk of cognitive impairment. Future studies are needed to determine whether targeted interventions for sarcopenic and dynapenic obesity can prevent or delay cognitive decline.