Prevalence, influencing factors, and dementia outcome of sarcopenic obesity in China

BACKGROUND: This study examines the epidemiology of sarcopenic obesity (SO) in China, focusing on national prevalence, modifiable influencing factors, and its longitudinal association with dementia risk in middle-aged and older adults. METHODS: Using the 2015 wave of the China Health and Retirement Longitudinal Study (CHARLS), SO prevalence was estimated nationally and regionally using Bayesian spatial modeling. Modifiable influencing factors were identified via multivariable logistic regression, with their relative contributions quantified using Extreme Gradient Boosting (XGBoost). The association between baseline SO (2015) and incident dementia risk (2018) was assessed using multivariable logistic regression. RESULTS: Among 10,256 participants aged ≥ 45 years, the national SO prevalence was 6.40% (95% Bayesian confidence intervals [BCIs]: 6.39-6.41%), with significant regional variation (Northern region: 8.60% [8.59-8.61%]; Southern region: 4.90% [4.86-4.94%]). Older age, female sex, hypertension, and depressive symptoms showed statistically significant associations with SO. Age emerged as the strongest predictor in XGBoost analysis. Compared to normal-weight individuals without sarcopenia, those with normal-weight sarcopenia had 63% higher dementia risk (odds ratio [OR] = 1.63; 95% confidence interval [CI]: 1.04-2.58), while SO individuals showed 89% increased risk (OR = 1.89; 95% CI: 1.67-2.15). CONCLUSION: These findings emphasize the significant geographic disparity in SO prevalence across China and reveal that SO is associated with a substantially elevated risk of dementia, underscoring the need for targeted interventions in aging populations.