| 1 BackgroundIn 2022,the population aged 65 and above in Shandong Province accounted for 16.72%of the province’s population,reaching a stage of moderate aging.The aging of population aging is becoming more and more serious,and the number of people with Alzheimer’s disease continues to increase.The "Healthy China Action(2019-2030)" has explicitly identified "the decrease of the prevalence rate of senile dementia among people aged 65 and above" as one of the important goals of China’s elderly health promotion action.Previous studies have focused on epidemiological investigations of various types of dementia,while this study focuses on the prodromal stage of dementia,i.e.,the stage of mild cognitive impairment.Mild cognitive impairment(MCI)is a clinical state between the normal cognitive state and dementia in older adults,mainly manifested by decreased memory,decreased attention,or mild impairment of functions in other cognitive fields,but without affecting the ability to daily life.It is an early but abnormal cognitive impairment state and a precursor to Alzheimer’s disease and other types of dementia.Studies have shown that patients with MCI are 10 times more likely to develop AD than normal older adults.The clinical outcomes of MCI patients include stable cognitive function,normal cognitive function,and dementia.The cognitive function of 14.4%-55.6%of the patients with MCI can be restored to normal,which provides an optimal intervention period for the secondary prevention of dementia.Implementing early screening and intervention for MCI patients,identifying relevant influencing factors at the MCI stage,actively preventing the occurrence of MCI,and delaying or preventing the development of MCI to AD and various types of dementia are not only conducive to improving the quality of life of older adults,promoting healthy aging,but also greatly reducing the burden on families and society,saving a lot of high-quality medical resources.The mental health of the elderly is closely related to their cognitive function.Depressive symptoms and anxiety symptoms can lead to cognitive decline.Elderly people with low subjective well-being are prone to produce negative emotions and negatively affect cognitive function.In addition,self-rated health status was associated with mental health,and elderly with poor self-rated health tended to have more health problems.The suffering of disease,coupled with the degradation of physical function and the decline of self-care ability,is easy to produce a large number of negative emotions,even anxiety,depression and other psychological problems,which may have a negative impact on their cognitive function.Zhaoyuan City is in a moderate aging stage and is about to reach a severe aging stage,with a high degree of aging.Therefore,the current status of MCI and related influencing factors in the local elderly aged 65 years and above in Zhaoyuan city were investigated,and explored whether self-rated health affects their cognitive function by affecting their mental health,so as to provide a reference for improving the cognitive ability of older adults and actively preventing the occurrence of MCI.2 Objectives(1)To investigate the MCI status of older adults aged 65 and above in Zhaoyuan City,Shandong Province.(2)To explore the impact of factors such as socio-demographic characteristics,lifestyle,health status,disease history,physiological characteristics,mental health,and self-rated health status of older adults on the stage of MCI,and to identify factors that may affect MCI.(3)To explore the mediating effect and mechanism of mental health between self-rated health and cognitive function in older adults.3 Methods3.1 SubjectsThis study was conducted from July 15 to October 8,2021,during the implementation of the "Health Examination Project for older adults aged 65 and above"(the National Basic Public Health Service Program),to investigate the current situation and influencing factors of MCI among older adults aged 65 and above in Zhaoyuan City,Shandong Province.Three research sites(Linglong Township,Daqinjia Sub-district Office and Mengzhi Sub-district Office)were selected by random sampling combined with the field environment in 9 towns and 5 Sub-district Offices in Zhaoyuan.A total of 2399 elderly people were surveyed,including 1973 elderly people(≥65)completed the scale evaluation and the questionnaire data and physical examination data were complete.649 dementia patients were excluded through the Mini-Mental State Examination(MMSE),and 1324 elderly people with MCI and normal cognitive function who met the inclusion and exclusion criteria of this study were included in this study.After the subjects consented and signed the informed consent form,a questionnaire survey was conducted.This study has been approved by the Research Ethics Committee of the Second Hospital of Shandong University(approval number,KYLL-2020(KJ)P-0142).3.2 ContentsThe general information questionnaire was used to collect data on demographic and sociological variables,lifestyle,health status and disease history,Self-assessment of health status.The cognitive ability of older adults was assessed by MMSE and the Montreal Cognitive Assessment Basic Scale(MoCA-BC).The Generalized Anxiety Disorder-7(GAD-7)、Patient Health Questionnaire-9(PHQ-9)and the World Health Organization Well-being Index Scale(WHO-5)were used to understand the mental health status of older adults.Data related to physical examination in older adults included height,weight,body mass index,waist circumference,blood pressure,resting heart rate,hemoglobin,white blood cell,platelet count,blood glucose,alanine aminotransferase,aspartate aminotransferase,total bilirubin,serum creatinine,urea nitrogen,total cholesterol,triglyceride,serum low density lipoprotein cholesterol and serum high density lipoprotein cholesterol.3.3 Statistical analysisEpidata 3.1 was used to establish the database,and IBM SPSS 24.0 and Process plug-in were used for data analysis.Descriptive analysis was used to understand the general situation of the subjects,and univariate analysis was used to test the differences in cognitive function of older adults in Zhaoyuan City with different social demographic characteristics,lifestyle,health status and disease history.Correlation analysis was used to explore the correlation between different physiological characteristics,different mental health and self-rated health status and cognitive function in older adults.Multiple linear regression model was used to explore the influencing factors of mild cognitive impairment.The Process plug-in was used to explore whether mental health mediates the relationship between self-rated health and cognitive function in older adults.4 Results4.1 Status of MCI in older adults in Zhaoyuan CityIn this survey,902 elderly people with MCI were screened out in the initial 1973 elderly people in Zhaoyuan City,and the overall prevalence of MCI was 45.7%.4.2 Influencing factors of MCI in older adults in Zhaoyuan CityThe results of univariate analysis showed that there were significant differences in the MoCA-BC scores of older adults in terms of gender,age,urban and rural origin,education level,marital status,retirement pension status,and economic status satisfaction among different sociodemographic characteristics(P<0.05);In terms of different lifestyles,there are differences in the MoCA-BC scores of older adults in terms of weekly exercise frequency,leisure and entertainment activities,smoking,drinking,and Internet use(P<0.05);There is a difference in MoCA-BC scores among older adults in terms of hearing loss(P<0.05).Pearson correlation analysis showed that MoCA-BC scores were negatively correlated with heart rate(r=-0.089,P=0.001);There is a positive correlation with hemoglobin level(r=0.110,P<0.001);Negatively correlated with platelet count(r=-0.081,P=0.003);There was a positive correlation between serum glutamic pyruvate transaminase(r=0.058,P=0.034)and serum creatinine(r=0.055,P=0.047);There was a negative correlation with urea nitrogen(r=-0.142,P<0.001)and total cholesterol levels(r=-0.065,P=0.018).Spearman correlation analysis showed that there was a negative correlation between MoCA-BC scores and depression(rs=-0.137,P<0.001),anxiety(rs=-0.068,P=0.013),and self-rated health status(rs=-0.106,P<0.001)in older adults;There is a positive correlation with subjective well-being(rs=0.146,P<0.001).The results of multiple linear regression analysis showed that the variables that ultimately entered the model included:living area,educational level,weekly exercise frequency,alcohol consumption,Internet use,hearing loss,depression,subjective well-being,and self-rated health status.The regression model was statistically significant(F=24.693,P<0.001).MoCA-BC score of the elderly living in the city was higher than that of older adults living in the countryside(β=0.109,P<0.001);Compared with older adults with education level of primary school or below,those with junior high school(β=0.0.298,P<0.001),high school education or above(β=0.367,P<0.001)had higher MoCA-BC scores.Participants who exercised 3-4 times per week had higher MoCA-BC scores than those who never exercised(β=0.067,P<0.05);Compared with older adults who never drank alcohol,older adults who drank alcohol occasionally(β=0.062,P<0.05)had higher MoCA-BC scores.Old people who used the Internet had higher MoCA-BC scores than those who did not use the Internet(β=-0.186,P<0.001);The MoCA-BC scores of older adults with significant hearing loss were lower than those of older adults without hearing loss(β=-0.050,P<0.05);The higher the depression score,the lower the MoCA score(β=-0.066,P<0.05);The higher the subjective well-being of older adults,the higher the MoCA score(β=0.053,P<0.05);The lower the self-rated health of older adults,the lower the MoCA-BC score(β=-0.059,P<0.05).4.3 The mediating effect of mental health between self-rated health and cognitive function in older adultsThe results of multi-factor analysis showed that self-rated health was the factor affecting cognitive function in older adults.The results of correlation analysis showed that there were pairwise correlations among the self-rated health status,depression,anxiety,and subjective well-being.In order to explore whether self-rated health affects cognitive function by affecting the mental health level of older adults,this study further analyzed the mediating role of mental health between self-rated health and cognitive function.Three mediating models of self-rated health—depression—cognitive function,self-rated health—anxiety—cognitive function,and self-rated health—subjective well-being—cognitive function were constructed.The results of mediating effect analysis showed that anxiety and subjective well-being did not mediate the relationship between self-rated health and cognitive function,while depression partially mediated the relationship between self-rated health and cognitive function.The total effect of self-rated health on cognitive function was-0.440(95%CI:-0.657,-0.222),the direct effect value was-0.333(95%CI:-0.562,-0.104),and the intermediate effect value of depression was-0.107(indirect effect),with an effect ratio of 24.32%.5 Conclusions(1)The prevalence rate of MCI in older adults aged 65 and above in Zhaoyuan City,Shandong Province was 45.7%.(2)Living area,education level,weekly exercise frequency,alcohol consumption,Internet access,hearing loss,depression,subjective well-being and self-rated health status were the influencing factors of MCI among older adults in Zhaoyuan City.(3)Depression partially mediated the relationship between self-rated health and cognitive function in the elderly,and the mediating effect accounted for 24.32%of the total effect.Self-rated health can not only directly affect cognitive function,but also indirectly affect cognitive function through depression.The worse the self-rated health,the more severe the depressive symptoms and the worse the cognitive function of older adults. |
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