Trends in the Prevalence of Cognitive Impairment Among Older Adults Aged 65 to 105 Years - China, 2002-2018

Introduction: This study aims to analyze trends and subgroup differences in the prevalence of cognitive impairment among older Chinese adults aged 65-105 years from 2002 to 2018. Methods: Data were drawn from six waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Cognitive function was measured using the Chinese version of the Mini-Mental State Examination (CMMSE). Cognitive impairment was determined by the total CMMSE score and educational attainment of participants. The generalized estimating equation (GEE) models with a logistic link and binominal distribution were performed to assess the secular trend in the prevalence. Results: The prevalence of cognitive impairment among older adults aged 65-105 years decreased from 3.44% [95% confidence interval (CI): 3.15%-3.73%] in 2002 to 2.41% (95% CI: 2.17%-2.65%) in 2018 in China. The prevalence was slightly higher in women than in men in 2002 (3.71% vs. 3.13% , P < 0.05), and there was no significant difference between women and men in 2018 (2.60% vs. 2.21% , P=0.12). Rural older adults had a higher prevalence of cognitive impairment before 2014, but their urban counterparts had a higher prevalence in 2018 (2.75% vs. 2.06% , P < 0.05). The GEE regression model showed that each successive year was associated with a 3% reduction in the odds of the prevalence of cognitive impairment [odds ratio (OR)=0.97; 95% CI: 0.97-0.97; P < 0.05]. Conclusions: The prevalence of cognitive impairment among Chinese older adults aged 65-105 years declined slowly from 2002 to 2018. The gender, urban-rural, age, and regional differences in the prevalence of cognitive impairment changed over time.