The updated prevalence and risk factors of dementia in old adults in China: A cross-sectional study

Background The continuously increasing aging population and life expectancy have led to an inconsistent and underestimated dementia prevalence in China. An updated epidemiologic study is urgently needed. Objective To update the prevalence rate and risk factors of dementia in China. Methods For this national cross-sectional study, 20,438 participants aged ≥65 from 28 communities and 56 villages from 14 centers were recruited using a multistage cluster sampling design between May 2019 and December 2019. Participants were assessed with a series of clinical and neuropsychological measurements. The prevalence rates of dementia, Alzheimer's disease (AD), and vascular dementia (VaD), as well as the risk factors, were calculated using multivariate-adjusted models. Results The crude prevalence rates were 9.1% (95% CI, 8.7%–9.5%) for dementia, 6.0% (95% CI, 5.7%–6.3%) for AD, 1.4% (95% CI, 1.2%–1.5%) for VaD, and 1.8% (95% CI, 1.6%–2.0%) for other dementias in a population aged ≥65 years. The overall sex- and age-standardized prevalence was 8.8%. Apart from VaD, the prevalence rates of dementia and AD were higher in females than males (10.3% versus 7.7%, respectively). Moreover, the prevalence rates of dementia and AD increased significantly with age. Being unmarried and having fewer social activities increased the risks of dementia and main subtypes. Risk factors were not exactly the same for participants with AD and VaD. Conclusions The prevalence of dementia is increased and almost comparable with that of developed countries for individuals aged ≥65 years. These findings may serve as new evidence for government interventions in aging.