Associations of Sarcopenia and Sarcopenic Obesity Using Different Obesity Definitions With Memory Decline.

Area of Science:

• Gerontology
• Neuroscience
• Public Health

Background:

• Sarcopenia, the age-related loss of muscle mass and strength, and sarcopenic obesity (SO), characterized by both low muscle mass and excess fat, are growing health concerns.
• Memory decline is a significant aspect of aging, impacting cognitive function and quality of life.

Purpose of the Study:

• To investigate the association between sarcopenia, SO, and memory function.
• To explore potential causal links between sarcopenia-related traits and memory using Mendelian randomization.

Main Methods:

• Cross-sectional and longitudinal analyses of data from the Guangzhou Biobank Cohort Study (GBCS) involving 6390 and 3979 participants, respectively.
• Sarcopenia defined by the Asian Working Group for Sarcopenia 2019 criteria; obesity assessed using 20 indicators.
• Memory evaluated using the Delayed Word Recall Test (DWRT); statistical analyses included linear regression and two-sample Mendelian randomization (2SMR).

Main Results:

• Sarcopenia was associated with lower baseline and follow-up DWRT scores and a faster rate of memory decline.
• Sarcopenic obesity defined by waist-to-hip-to-height ratio (WHHR) showed stronger associations with memory decline than sarcopenia or obesity alone.
• Two-sample Mendelian randomization indicated a positive association between walking pace (a sarcopenia indicator) and working memory.

Conclusions:

• Sarcopenia and SO are significantly associated with accelerated memory decline.
• The central obesity indicator WHHR may serve as a more effective predictor of late-life memory decline in the context of SO.
• These findings highlight the importance of body composition in cognitive aging and suggest targeted interventions for memory preservation.