Sarcopenia and mild cognitive impairment in older adults from six low- And middle-income countries

Background: Little is known about the relationship between sarcopenia and mild cognitive impairment (MCI) in low- and middle-income countries (LMICs). Objective: This study aimed to investigate this association among community-dwelling adults aged≥65 years from six LMICs. Methods: Cross-sectional, nationally representative data from the Study on Global Ageing and Adult Health (SAGE) were analyzed. These data were obtained in China, Ghana, India, Mexico, Russia, and South Africa in 2007-2010. Participants were considered to have sarcopenia if they had low skeletal muscle mass (i.e., lower skeletal mass index) and a weak handgrip strength. MCI was defined using the National Institute on Aging-Alzheimer's Association criteria. Multivariable logistic regression analysis was conducted to assess associations. Results: The final analytical sample consisted of 12,912 individuals aged≥65 years with preservation in functional abilities without stroke (mean [standard deviation] age 72.2 [10.8] years; 45.2% males). The overall prevalence of sarcopenia and MCI were 11.3% and 18.1%, respectively. After adjusting for potential confounders, there was a positive association between sarcopenia and MCI in all countries (i.e., odds ratio [OR] > 1) with the exception of South Africa, and the overall estimate was OR = 1.60 (95% confidence interval [CI] = 1.32-1.93) with a low level of between-country heterogeneity (I2 = 0.0%). Conclusion: There was a positive association between sarcopenia and MCI in this sample of older adults living in LMICs. Causality should be assessed in future longitudinal research, while the utility of sarcopenia as a marker of MCI should also be investigated.