Prevalence, trends and distribution of dementia among older adults from 1990 to 2023 in China: A comprehensive systematic review and meta-analysis

OBJECTIVE: Dementia among the older adults represents a significant public health challenge in China, particularly in light of the country's evolving socioeconomic conditions and demographic transformations. This meta-analysis of recent research focuses on quantifying the prevalence of dementia among older adults in China between 1990 to 2023. Additionally, it explores the prevalence of dementia within specific demographic groups. DESIGN: A systematic review and meta-analysis. METHODS: A comprehensive search of the PubMed/MEDLINE, Embase, Web of Science, and Cochrane databases was conducted from their inception until September 2024. The search used terms like "dementia", "prevalence" and "China", combined with specific filters. Studies were included if they reported dementia prevalence data among adults in China. Two reviewers independently extracted data on study characteristics, total sample size, and dementia cases, and assessed study quality using predefined criteria. The overall dementia prevalence was calculated by pooling estimates with 95 % CIs. Subgroup analyses were performed based on age, sex, region, and study quality. RESULTS: A total of 132 studies involving 681,074 participants and 35,141 people with dementia from 32 provinces in China were identified. The overall pooled prevalence of dementia was found to be 4.76 %. Furthermore, the pooled prevalence of dementia exhibited a gradual increase from 1990 (2.43 %) to 2023 (5.74 %). Notably, when classified into different subgroups by economic development level, individuals residing in underdeveloped regions exhibited a prevalence of 5.82 %. In contrast, when categorized by geographical location, those in the Northeast demonstrated a prevalence of 13.66 %. The prevalence was notably higher among females, recorded at 7.94 %, in contrast to males, which stood at 4.00 %. Additionally, individuals aged over 90 years exhibited a prevalence of 32.92 %, significantly higher than those in the 60-70 age group (2.07 %), 70-80 age group (5.26 %), and 80-90 age group (14.03 %). CONCLUSIONS: The prevalence of dementia in China is considerable, currently estimated at 4.76 % with an upward trend since 1990. It affects nearly one-third of those aged 90 and older, with clear disparities by sex, age, and region. These findings highlight the need for targeted prevention and early detection among high-risk groups. REGISTRATION: INPLASY2024120073.