Correlation of sarcopenic obesity with mild cognitive impairment in middle-aged and older adults: a prospective cohort study based on the nationwide longitudinal survey of CHARLS

Sarcopenic obesity (SO), characterized by concurrent muscle loss and excess adiposity, is an emerging public health challenge, yet prospective evidence linking SO to mild cognitive impairment (MCI) remains limited. Baseline data were collected from the China Health and Retirement Longitudinal Study (CHARLS) in 2015. The incidences of MCI during follow-ups by 2018 and 2020 were calculated. Participants were divided into healthy, obesity only, sarcopenia only, and SO groups. Aging-associated MCI was defined as a total cognitive score at least one standard deviation below the age-specific norm for participants aged 45 and above, adjusted for age in five-year increments. In the 11,674 individuals with an average age of 59.31 ± 9.21 years, SO was detected in 160 (1.37%) individuals. The score of each dimension and total score of cognitive function were lower in the SO group than in the sarcopenia-only group, but with a difference only in the dimension of drawing (P = 0.012). By 2018, 840 MCI cases (12.7%), and by 2020, 1,107 (16.8%) MCI cases were reported. The MCI incidence was higher in the SO group than in the other groups (P < 0.001). The risk of MCI was higher in the SO group than in the other groups (3-year MCI: hazard ratio [HR] 2.11, 95% confidence interval [CI] 1.21, 3.69, P = 0.008; 5-year MCI: HR 1.88, 95% CI 1.09, 3.25, P = 0.024). Older adults and women were more vulnerable to MCI induced by SO. SO is correlated with MCI and serves as a risk factor in middle-aged and older adults in China.