Prevalence,Incidence,and Progression Of Cognitive Impairment,No Dementia Among Rural-Dwelling Chinese Older Adults

Background:Cognitive impairment,no dementia(CIND)is considered as an intermediate state between normal cognitive aging and dementia.People with CIND might be at a substantial risk for progressive cognitive decline and dementia.However,few studies have examined the risk factors of cognitive impairment,no dementia(CIND),dementia,and the progression from CIND to dementia in rural China.Objective:To determine the prevalence and incidence of CIND in rural-dwelling Chinese older adults,and to examine the risk factors associated with risks of CIND,dementia,and the transition from CIND to dementia.Methods:This research was based on the Shandong Yanggu Study of Aging and Dementia(SYS-AD)and the Multimodal Interventions to Delay Dementia and Disability in Rural China(MIND-China).Totally 2,781 dementia-free participants(age≥65 years)undertook the baseline examinations in the SYS-AD project(2014)and follow-up examinations in the MIND-China project(2018).Demographic,epidemiological,clinical,and neuropsychological data were collected following a structured questionnaire.We defined CIND according to subjective cognitive complaints and the age-and education-specific Mini-Mental State Examination(MMSE)score.We diagnosed dementia according to the DSM-IV criteria.Data were analyzed with the multinomial logistic regression models.Results:The overall prevalence of CIND was 10.54%at baseline and the incidence was 28.26 per 1,000 person-years.CIND at baseline was associated with the multi-adjusted odds ratio(OR)of 2.06(95%confidence interval=1.23-3.47)for incident dementia.Among participants free of CIND at baseline,being women and having lower social support were related to the incidence of CIND in 4 years,with ORs(95%CIs)being 2.21(1.51-3.23)and 1.62(1.00-2.61),respectively.Among all participants at baseline,older age,illiteracy,and a history of stroke were associated with the incidence of dementia in 4 years,with ORs(95%CIs)being 1.14(1.09-1.18),3.42(95%CI 1.90-6.16)and 2.91(1.47-5.74),respectively.Among participants with CIND at baseline,older age was associated with higher incidence of dementia with OR(95%CI)being 1.12(1.03-1.21).Conclusions:CIND affects over 10%of older adults living in rural communities of western Shandong province.People with CIND are twice as likely to have dementia as those without CIND.Female sex and lower social support are risk factors of CIND;older age,illiteracy,and stroke are risk factors of dementia.Older age is associated with an increased risk of progression from CIND to dementia.