Construction And Empirical Study Of Multidomain Dementia Prevention Program For Older Adults Based On Life-Course Model Of Dementia Risk Factors

Background:Dementia have emerged as one of the greatest global challenges for health and social care in the 21st century.Given the high prevalence and large human,social and economic burdens of dementia in China,delaying cognitive decline and preventing dementia have become major public health priorities in achieving a healthy China.The Lancet Commission on Dementia Prevention,Intervention,and Care proposed a life-course model of dementia risk that suggests that approximately 40%of dementia worldwide is attributable to 12 modifiable risk factors at different phases of the lifespan.Given the large number of modifiable risk factors,nonpharmacological interventions addressing risk factors might prevent cognitive impairment or dementia.Furthermore,cognitive impairment and dementia are multifactorial and heterogeneous in nature,and multidomain interventions that target several risk factors simultaneously may achieve optimal preventive effects.Our previous meta-analysis found that multidomain interventions exhibited small but significant effects in reducing dementia risk and increasing cognitive composite scores.The relatively small effect sizes for multidomain interventions suggest that there could be some gaps in the current study.Due to the time-dependent effects of specific dementia risk factors(obesity and hypertension in midlife),existing multidomain interventions do not incorporate the life-course model of risk factors for dementia,resulting in a lack of tailored interventions for people of different ages and risk characteristics.Additionally,multidomain interventions mainly focus on cardiovascular risk factors(such as exercise,diet,hypertension,and obesity)and lack dementia-specific risk factors,such as social isolation.Importantly,most of the current evidence on multidomain interventions comes from Western countries,which could result in existing multidomain interventions not being suitable for the Chinese public due to different geographical,economic,and cultural factors.Therefore,it is of great significance to construct a more comprehensive,accurate,and suitable multidomain dementia prevention program for Chinese public,combined with the life-course model of dementia risk factors,to effectively prevent or delay the development of dementia.Objectives:In a proof-of-concept trial,we aimed to investigate the effectiveness of a multidomain intervention based on a life-course model of modifiable risk factors for dementia in Chinese at-risk older adults.Methods:(1)Summarizing the evidence for multidomain dementia prevention interventions:Five electronic databases,Pub Med,Embase,Cochrane Library,CINAHL,and Psyc INFO,were systematically searched from inception to April 17,2021.Randomized controlled trials that assessed multidomain lifestyle interventions on the outcomes of cognition or dementia risk were included.The standardized mean difference(Hedges’g)was calculated using random-effects models.Risk of bias was assessed using the Revised Cochrane risk-of-bias assessment tool for randomized trials(Ro B2),and the certainty of evidence assessed using the five Grading of Recommendations Assessment,Development and Evaluation(GRADE)criteria.Subgroup analyses were performed to explore the impacts of the study,participants,and intervention characteristics on the effect size.To further confirm the effectiveness of multidomain dementia prevention interventions and to determine the optimal elemental of multidomain interventions.(2)Analysis of the current occurrence and perception of 12 dementia risk factors in the life-course model:A cross-sectional online survey was conducted among 760Chinese community residents over 18 years old and above on the prevalence of 12 risk factors,dementia risk scores,and knowledge,beliefs,and behaviors regarding dementia prevention.Multivariate logistic regression was used to explore the influencing factors of knowledge and belief,and to identify the impact of knowledge and beliefs on dementia risk scores and prevention behaviors.Additionally,interactions between knowledge(or belief)and potential confounders were assessed.The effect of knowledge and beliefs on reducing dementia risk scores and promoting beneficial behaviors was estimated in each subgroup of the confounder if the interaction term with the confounder was significant.Adapting recruitment population and program content of the multidomain interventions to guide the development of prevention programs.(3)Exploring motivations and barriers for older people to engage in dementia prevention:A purposive sampling method was used to conduct one-to-one Semi-structured interviews with 23 high-risk older adults.A qualitative inductive content analysis method was used for data analysis to gain insight into older people’s perceptions and attitudes towards dementia prevention,and their needs and preferences for intervention programs.Combined with the results of the previous quantitative study,we provide insight into the specific aspects of dementia knowledge deficits among older people,and explores motivations and barriers for older people to engage in dementia prevention.To optimize intervention design and guide the development of intervention programs that provide a realistic basis for the development of dementia prevention programs.(4)Constructing multidomain dementia prevention program for older adults based on life-course model of dementia risk factors:Guided by social cognitive theory,based on the framework of the life-course model of dementia risk factors,and based on preliminary evidence,questionnaires,interview results and the latest guideline recommendations,we constructed the first draft of a multidomain dementia prevention program for older adults based on life-course model,and established the final draft of the multidomain interventions through a Delphi expert consultation.(5)Empirical study of multidomain dementia prevention program for older adults based on life-course model of dementia risk factors:A total of 48 pairs of participants were randomly assigned.Participants were randomized in a 1:1 ratio to either the multidomain intervention group or the control group using a computerized random number generator.Participants allocated to the intervention group(N=48)received multidomain dementia prevention program for older adults based on life-course model of dementia risk factors for 6 months,including face-to-face interviews,online messaging,and community activities.The control group received health education on dementia knowledge.Participants allocated to the control group(N=48)received health education on dementia knowledge.Assessments were conducted at baseline,3months,and 6months by researchers blinded to the allocation.The assessment measures included cognitive composite score,dementia risk scores,dementia literacy and beliefs,dementia risk factors,and social isolation.Data were analyzed using T-tests,Mantel-Haenszel tests,X~2 tests,mixed effects models,multivariate logistic regression,generalized estimating equations,the paired samples t-test,Wilcoxon signed rank test and Mc Nemar’s test.The interaction effect of subgroup and treatment effect was tested to explore the influence of covariates on the effect of multidomain interventions.To validate the feasibility and effectiveness of multidomain dementia prevention program for older adults based on life-course model of dementia risk factors.Results:(1)Summarizing the evidence for multidomain dementia prevention interventions:Seventeen randomized controlled trials(RCTs)involving 12,312 participants were included.The meta-analysis indicated that multidomain interventions showed small but significant effects on both the risk of dementia(SMD=-0.11;95%CI,-0.18 to-0.05;P<0.001;I~2=0%;6RCTs,1981 participants)and the cognitive composite score(SMD=0.10;95%CI,0.02 to 0.17;P=0.012;I~2=27.5%;7 RCTs,2643 participants).No significant improvements were found in global cognition(SMD=-0.04;95%CI,-0.12to 0.04;P=0.330;I~2=38.3%;9 RCTs,3740 participants).The subgroup analyses found that the effect sizes of multidomain interventions including physical,cognitive,and social factors were larger than those without these three lifestyle factors(-0.24 VS-0.10).Our findings provide preliminary confirmation of the potential of multidomain interventions to prevent dementia.The effectiveness of multidomain interventions with specific combinations of physical,cognitive,and social factors for preventing dementia should be further determined.The dementia risk score and cognitive composite scores could be evaluated in dementia prevention trials.(2)Analysis of the current occurrence and perception of 12 dementia risk factors in the life-course model:The respondents were 760 adults.Three dementia risk factors were significantly more prevalent in the present study than in worldwide estimates:less education in early life(59.4%VS 40.0%),hypertension in midlife(28.8%VS 8.9%),and physical inactivity in later life(48.9%VS 17.7%).Knowledge(OR=0.95;95%CI,0.91 to 0.99;P=0.007)and beliefs(OR=0.82;95%CI,0.72 to 0.93;P=0.003)were associated with dementia risk scores.Additionally,lower perceived susceptibility(OR=1.68;95%CI,1.04 to 2.72)and higher perceived benefits(OR=0.68;95%CI,0.57 to 0.80)were associated with lower dementia risk scores.Knowledge of the 12modifiable dementia risk factors in the life-course model was low.Five factors achieved moderate literacy levels and the remaining seven risk factors were correctly endorsed by less than 50%of respondents.The correct recognition rate of overall dementia prevention knowledge was even lower at 43.5%,especially among older and less educated people.Subgroup analyses revealed that higher knowledge scores were associated with adequate cognitive activities(OR=1.22;95%CI,1.09～1.35;P=0.001)and lower dementia risk scores(OR=0.84;95%CI,0.75～0.93;P=0.001)in older adults aged 60 years and over.Our founding reveal that older people are at higher dementia risk,have lower levels of dementia knowledge and beliefs,and are priority population for dementia prevention trials.Multidomain interventions should increase knowledge and belief regarding dementia prevention in older adults and enhance perceptions of susceptibility and benefits of dementia.(3)Exploring motivations and barriers for older people to engage in dementia prevention:The respondents were 23 high-risk older adults.Six main categories were eventually generated,including perceptions of dementia,risk factors,and prevention,attitudes to dementia,factors of dementia prevention,needs and preferences.Knowledge of dementia prevention in older people is limited,knowledge of the symptoms and prevention methods is partial,and knowledge of the causes and risk factors is inadequate and often misunderstood.Internal factors influencing older adults to engage in dementia prevention include prevention knowledge,perceived benefits,fear and worry,and health status,while external factors include lack of resources,uncertainty of Internet information,living burden and social support.Our results found that all older adults were eager to receive information on dementia prevention.Multidomain interventions should emphasize the perceived benefits of behavior change,clarify mechanisms of effectiveness,and provide practical guidance.Multidomain interventions should be implemented in a community-based manner,led by health professionals,with multiple forms of dementia prevention education.(4)Constructing multidomain dementia prevention program for older adults based on life-course model of dementia risk factors:Based on a life-cycle model of dementia risk factors,preliminary evidence,questionnaires,interview results and the latest guideline recommendations were used to identify the intervention population,program modules,program priorities and delivery methods.Fifteen experts completed two rounds of Delphi expert correspondence.The experts have a high level of judgement(Ca=0.94)and familiarity(Cs=0.86)with the content of correspondence consultation.The Kendall’s W for the two rounds of correspondence was 0.319 and 0.335respectively(P<0.05),with coefficients of variation less than 0.25.The final draft of the multidomain dementia prevention program for older adults based on life-course model was established through a Delphi expert consultation,which contains 5 primary indicators,17 secondary indicators and 32 tertiary indicators.(5)Empirical study of multidomain dementia prevention program for older adults based on life-course model of dementia risk factors:No significant differences in the socio-demographic variables and baseline data were observed across the groups(P>0.05).In terms of cognitive function,the cognitive composite Z score increased over time in the multidomain interventions group compared to the control group(P=0.013).Of the cognitive subdomains,only DSST significantly increased in the multidomain interventions group(P=0.020).In terms of dementia risk scores,the total ANU-ADRI scores(P<0.001),and its subdomains protective factors scores(P=0.001)and risk factors scores(P=0.049),decreased over time in the multidomain interventions group compared to the control group.There was a trend towards a reduction in the number of dementia risk factors in the multidomain interventions group,but no significant difference between the two groups(P=0.063).For the three factors of social isolation,ULS-8 decreased over time in the multidomain interventions group compared to the control group(P=0.029).However,no significant difference in the social contact and social participation between the two groups(P>0.05).In terms of dementia prevention knowledge and beliefs,both knowledge scores(P<0.001)and MCLHB-DRR(P<0.001)increased over time in the multidomain interventions group compared to the control group.For the three behaviors of dementia prevention,physical(P=0.044)and cognitive activities(P=0.013)increased over time in the multidomain interventions group compared to the control group.However,no significant difference in the social activities between the two groups(P=0.084).Conclusions:(1)Multidomain interventions may reduce the dementia risk and improves cognitive function,which has the potential to prevent dementia.Additionally,multidomain interventions improved knowledge,beliefs,and behaviors regarding dementia prevention,increased physical and cognitive activity and had a tendency to increase social activity,indicating the feasibility and effectiveness of the multidomain dementia prevention interventions based on life-course model.(2)Multidomain dementia prevention interventions have a good safety profile and is a suitable for high-risk older people in China.More importantly,our study is a pragmatic community-based intervention implemented online and face-to-face,which can be replicated and implemented on a large scale in grassroots communities to reduce the incidence of dementia in the public and promote the Healthy China Initiative.