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

Aims
To explore the associations of sarcopenia and sarcopenic obesity (SO) with memory.

Materials and Methods
Data from the Guangzhou Biobank Cohort Study (GBCS) were used to conduct both cross-sectional (n = 6390) and longitudinal (n = 3979) analyses. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019, while obesity was defined by 20 obesity indicators. Memory was assessed by the Delayed Word Recall Test (DWRT). Linear regression was used to analyze these associations. Two-sample Mendelian randomization (2SMR) was used to investigate potential causal associations of sarcopenia-related traits with memory.

Results
Compared to participants without sarcopenia, those with sarcopenia had lower baseline and follow-up DWRT score, and greater decrease in mean annual change (MAC) and MAC rate of DWRT score, with adjusted βs (95% CIs) being −0.24 (−0.33 to −0.14), −0.10 (−0.20 to −0.004), −0.03 (−0.06 to −0.001) and −0.79 (−1.57 to −0.01), respectively. Among all the SO definitions, the associations of SO defined by waist-to-hip-to-height ratio (WHHR) appeared to be the strongest (−0.36 [−0.50 to −0.22], −0.31 [−0.45 to −0.17], −0.09 [−0.14 to −0.05] and −2.70 [−3.81 to −1.59]), and stronger than those with sarcopenia only or obesity only. In 2SMR, walking pace (one of the sarcopenia indicators) was positively associated with working memory (1.61 [0.59, 2.62]).

Conclusions
Sarcopenia and SO were associated with faster memory decline. Using the central obesity indicator WHHR to define SO may better predict late-life memory.