Associations of metabolic obesity phenotypes with cognitive aging in middle-aged and elderly Chinese adults

CONTEXT: Previous research has demonstrated that metabolic abnormalities accelerate cognitive aging. Although obesity is closely linked to metabolic disorders, it exhibits considerable heterogeneity depending on an individual's metabolic status. However, the relationship between this metabolic heterogeneity in obesity and cognitive aging remains unclear. OBJECTIVE: We aimed to analyze the effects of various metabolic obesity phenotypes on cognitive aging. METHODS: A total of 7521 participants aged over 45 years from the China Health and Retirement Longitudinal Study (CHARLS) were included. Cognitive function was evaluated through both episodic memory and executive function. The relationship between different metabolic obesity phenotypes and cognitive aging was analyzed using linear mixed models, based on baseline metabolic obesity phenotypes: metabolically healthy normal weight (MHNW), metabolically healthy overweight/obesity (MHOO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight/obesity (MUOO). RESULTS: Compared with MHNW, MUNW was associated with accelerated aging of global cognitive function (β = -0.007, 95 % CI: -0.013 to -0.001) and episodic memory (β = -0.008, 95 % CI: -0.016 to -0.001). In contrast, MHOO was associated with a slower decline in episodic memory (β = 0.011, 95 % CI: 0.002 to 0.020). However, none of the metabolic obesity phenotypes showed significant differences in executive function decline compared to MHNW. CONCLUSIONS: Overall, the MUNW phenotype was associated with accelerated aging of global cognitive function and episodic memory, while the MHOO phenotype was associated with a slower decline in episodic memory compared to MHNW. The MUOO group did not differ significantly from MHNW in the three dimensions of cognitive aging.