| Background:Subjective cognitive decline(SCD)refers to the stage in which individuals continue to experience a decline in self-perceived cognitive function,but the relevant neuropsychological tests remain within the normal range.In Alzheimer’s disease(AD)-related studies,SCD was recognized as a possible earliest prodromal and preclinical stage that could be identified in the continuous progressive duration of AD.Few studies have examined the occurrence and progression of SCD in rural Shandong,China,and its predictive value to the progression of cognitive impairment,as well as progression-related factors,need to be verified and explored through cohort studies.Objective:1.To investigate the prevalence of SCD among rural-dwelling older adults who are free of cognitive impairment in Shandong province;2.To determine whether the risk of subsequent cognitive impairment,no dementia(CIND),AD,and vascular dementia(VaD)increased in elderly with SCD,as well as their respective incidence density;3.To explore the risk and protective factors associated with progression from SCD to CIND,AD,and VaD.Methods:This study was based on the Shandong Yanggu Study of Aging and Dementia(SYS-AD).The community-based prospective cohort study included 2488 objective cognitively unimpaired participants(age≥65 years)in Yanlou Town,Yanggu County,Liaocheng City,Shandong Province who were examined at baseline from 2014 to 2015.Demographic,lifestyle,neuropsychological and clinical data were collected through semi-structured interviews,physical examinations,and laboratory tests.The follow-up survey was conducted in the Multimodal Interventions to Delay Dementia and Disability in Rural China(MIND-China)project in 2018.SCD was defined as normal objective cognitive performances and the Chinese version of the self-rated Ascertain Dementia 8-item Questionnaire(AD8)score≥2.CIND,AD,and VaD were diagnosed following the international criteria.Data were analyzed with the multinomial logistic regression models to determine the role of SCD in the progression of dementia and its related factors.Results:1.The overall prevalence of SCD was 40.07%among cognitively unimpaired participants at baseline.The prevalence of SCD increased with age.2.Compared with non-SCD,having SCD at baseline was significantly associated with the multi-adjusted odds ratio(OR)of 1.49(95%confidence interval=1.09-2.05;P=0.014)for incident CIND and 3.11(95%CI=1.63-5.91;P=0.001)for incident AD,however,no significant difference was found in VaD.Of 1098 non-SCD participants,the incidence of CIND,AD,and VaD was 22.57,3.59,and 2.87 per 1,000 person-years,respectively.While of 745 participants with SCD at baseline,the incidence of CIND,AD,and VaD was 37.14,15.22,and 4.60 per 1,000 person-years,respectively.3.After adjusting for multiple covariates,older age(per 1-year increment)(OR=1.22;95%CI 1.14-1.31;P<0.001),carrying the apolipoprotein E(APOE)s4 allele(OR=2.70;95%CI 1.14-6.36;P=0.024),and mild depressive symptoms(OR=3.74;95%CI 1.30-10.74;P=0.014)were associated with an increased risk of progression from SCD to AD.High education(OR=0.31;95%CI 0.11-0.87;P=0.027),and better social support(OR=0.32;95%CI 0.13-0.84;P=0.020)were associated with a decreased risk of progression from SCD to AD.Whereas obesity(OR=6.28;95%CI 1.67-23.66;P=0.007)and stroke history(OR=4.38;95%CI 1.04-18.47;P=0.044)were relevant to SCD progression to VaD.Conclusions:SCD affects over 40%of rural-dwelling older adults who are free of cognitive impairment in Shandong,China.Older people with SCD are more likely to develop CIND and AD than those without SCD.Older age,illiteracy,APOE ε4 allele,low social support,and depressive symptoms are risk factors for SCD progression to AD,whereas obesity and stroke history are risk factors for progression to VaD. |
PDF Full Text Request