Prevalence, risk factors, and management of dementia and mild cognitive impairment in adults aged 60 years or older in China: a cross-sectional study

China has a large population of older people, but has not yet undertaken a comprehensive study on the prevalence, risk factors, and management of both dementia and mild cognitive impairment (MCI). For this national cross-sectional study, 46 011 adults aged 60 years or older were recruited between March 10, 2015, and Dec 26, 2018, using a multistage, stratified, cluster-sampling method, which considered geographical region, degree of urbanisation, economic development status, and sex and age distribution. 96 sites were randomly selected in 12 provinces and municipalities representative of all socioeconomic and geographical regions in China. Participants were interviewed to obtain data on sociodemographic characteristics, lifestyle, medical history, current medications, and family history, and then completed a neuropsychological testing battery administered by a psychological evaluator. The prevalence of dementia (Alzheimer's disease, vascular dementia, and other dementias) and MCI were calculated and the risk factors for different groups were examined using multivariable-adjusted analyses. Overall age-adjusted and sex-adjusted prevalence was estimated to be 6·0% (95% CI 5·8–6·3) for dementia, 3·9% (3·8–4·1) for Alzheimer's disease, 1·6% (1·5–1·7) for vascular dementia, and 0·5% (0·5–0·6) for other dementias. We estimated that 15·07 million (95% CI 14·53–15·62) people aged 60 years or older in China have dementia: 9·83 million (9·39–10·29) with Alzheimer's disease, 3·92 million (3·64–4·22) with vascular dementia, and 1·32 million (1·16–1·50) with other dementias. Overall MCI prevalence was estimated to be 15·5% (15·2–15·9), representing 38·77 million (37·95–39·62) people in China. Dementia and MCI shared similar risk factors including old age (dementia: odds ratios ranging from 2·69 [95% CI 2·43–2·98] to 6·60 [5·24–8·32]; MCI: from 1·89 [1·77–2·00] to 4·70 [3·77–5·87]); female sex (dementia: 1·43 [1·31–1·56]; MCI: 1·51 [1·43–1·59]); parental history of dementia (dementia: 7·20 [5·68–9·12]; MCI: 1·91 [1·48–2·46]); rural residence (dementia: 1·16 [1·06–1·27]; MCI: 1·45 [1·38–1·54]); fewer years of education (dementia: from 1·17 [1·06–1·29] to 1·55 [1·38–1·73]; MCI: from 1·48 [1·39–1·58] to 3·48 [3·25–3·73]); being widowed, divorced, or living alone (dementia: from 2·59 [2·30–2·90] to 2·66 [2·29–3·10]; MCI: from 1·58 [1·44–1·73] to 1·74 [1·56–1·95]); smoking (dementia: 1·85 [1·67–2·04]; MCI: 1·27 [1·19–1·36]), hypertension (dementia: 1·86 [1·70–2·03]; MCI: 1·62