A multicentre community-based study of dementia cases and subcases in older people in China-the GMS-AGECAT prevalence and socio-economic correlates

Background Previous studies indicated overall relatively low prevalence of dementia in older people in China, which may be biased by studied samples or methods. We determined the prevalence of dementia cases and subcases in China and examined their socio-economic correlates. Methods Using the Geriatric Mental State interview, we examined random samples of 2917 participants aged?=?65?years in urban and rural Anhui, China in 20012003, and 3327 in four other provinces in 20082009. Dementia cases and subcases were diagnosed by Geriatric Mental State-Automated Geriatric Examination for Computer Assisted Taxonomy. Results Age-standardised prevalence for cases and subcases of dementia in the Anhui elders was 7.20% (95%CI 6.29%8.20%) and 10.5% (9.38%11.6%), and in the four provinces, 9.86% (8.80%10.9%) and 8.51% (7.51%9.52%). The matched figures among the participants who were literate were 3.05% (2.08%4.02%) and 10.0% (8.38%11.6%), and 4.92% (3.89%5.96%) and 6.76% (5.55%7.96%), respectively. There were higher prevalence rates of dementia cases and subcases in the rural elders than in the urban. Both the Anhui and four-province studies showed an obvious association of dementia with higher and lower incomes among elders who had lower educational levels or had the lowest occupational class. The highest risk of dementia was found in those who were illiterate but had the highest income or had the job of business/nonmanual labouring. Conclusions People in China have a higher prevalence of dementia than previously reported. Its U-shaped relationship with income and the excess subcases prevalence predicates a significant burden of disease, both now and for the future, suggesting preventive strategy for dementia in China. Copyright (c) 2011 John Wiley & Sons, Ltd.