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Mapping the complexity of dementia: factors influencing cognitive function at the onset of dementia

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Background Dementia is a multi-factorial condition rather than a natural and inevitable consequence of ageing. Some factors related to dementia have been studied much more extensively than others. To gain an overview of known or suspected influential factors is a prerequisite to design studies that aim to identify causal relationships and interactions between factors. This article aims to develop a visual model that a) identifies factors related to cognitive decline that signal the onset of dementia, b) structures them by different domains and c) reflects on and visualizes the possible causal links and interactions between these factors based on expert input using a causal loop diagram. Method We used a mixed-method, step-wise approach: 1. A systematic literature review on factors related to cognitive decline; 2. A group model building (GMB) workshop with experts from different disciplines; 3. Structured discussions within the group of researchers. The results were continuously synthesized and graphically transformed into a causal loop diagram. Results The causal loop diagram comprises 73 factors that were structured into six domains: physical (medical) factors (23), social health factors (21), psychological factors (14), environmental factors (5), demographic factors (5) and lifestyle factors (3). 57 factors were identified in the systematic literature review, additionally 16 factors, mostly of the social health cluster, were identified during the GMB session and the feedback rounds. Conclusion The causal loop diagram offers a comprehensive visualisation of factors related to cognitive decline and their interactions. It supports the generation of hypotheses on causal relationships and interactions of factors within and between domains.
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Seifertetal. BMC Geriatrics (2022) 22:507
https://doi.org/10.1186/s12877-022-02955-2
RESEARCH
Mapping thecomplexity ofdementia:
factors inuencing cognitive function
attheonset ofdementia
Imke Seifert1*, Henrik Wiegelmann2, Marta Lenart‑Bugla3, Mateusz Łuc3, Marcin Pawłowski3, Etienne Rouwette4,
Joanna Rymaszewska3, Dorota Szcześniak3, Myrra Vernooij‑Dassen5, Marieke Perry6, René Melis6,
Karin Wolf‑Ostermann2, Ansgar Gerhardus1, on behalf of the SHARED consortium
Abstract
Background: Dementia is a multi‑factorial condition rather than a natural and inevitable consequence of ageing.
Some factors related to dementia have been studied much more extensively than others. To gain an overview of
known or suspected influential factors is a prerequisite to design studies that aim to identify causal relationships and
interactions between factors. This article aims to develop a visual model that a) identifies factors related to cognitive
decline that signal the onset of dementia, b) structures them by different domains and c) reflects on and visualizes the
possible causal links and interactions between these factors based on expert input using a causal loop diagram.
Method: We used a mixed‑method, step‑wise approach: 1. A systematic literature review on factors related to cogni‑
tive decline; 2. A group model building (GMB) workshop with experts from different disciplines; 3. Structured discus‑
sions within the group of researchers. The results were continuously synthesized and graphically transformed into a
causal loop diagram.
Results: The causal loop diagram comprises 73 factors that were structured into six domains: physical (medical) fac‑
tors (23), social health factors (21), psychological factors (14), environmental factors (5), demographic factors (5) and
lifestyle factors (3). 57 factors were identified in the systematic literature review, additionally 16 factors, mostly of the
social health cluster, were identified during the GMB session and the feedback rounds.
Conclusion: The causal loop diagram offers a comprehensive visualisation of factors related to cognitive decline and
their interactions. It supports the generation of hypotheses on causal relationships and interactions of factors within
and between domains.
Keywords: Dementia, Model, Theory, Risk factors, Cognition
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Introduction
Dementia is a multi-factorial condition that is a major
cause of disability and dependency among older people.
Worldwide, 50 million people live with a diagnosis of
dementia and the number is projected to reach 152 mil-
lion in 2050 [1]. It not only causes substantial challenges
for the individuals living with dementia themselves, but
also for their families and caregivers [24]. In addition
to physical and emotional distress, dementia causes sub-
stantial economic burdens for both individuals and socie-
ties [1].
Open Access
*Correspondence: imke.seifert@uni‑bremen.de
1 Department for Health Services Research, Institute of Public Health
and Nursing Research (IPP), Health Sciences Bremen, University
of Bremen, Grazer Straße 4 , 28359 Bremen, Germany
Full list of author information is available at the end of the article
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Seifertetal. BMC Geriatrics (2022) 22:507
Previous research has identified a wide array of
factors potentially related to cognitive decline and
dementia. Well studied risk factors include genetic pre-
conditions, life-style related factors, such as physical
inactivity, tobacco use, unhealthy diets, harmful use of
alcohol, and medical conditions, such as hypertension,
diabetes, hypercholesterolemia, obesity and depression
[1, 5]. Other contributing factors, such as environmen-
tal and social health factors have been less intensively
researched, however there are strong indications that
these might influence the onset of dementia and its fur-
ther trajectory [69].
Although dementia is considered a multi-factorial
condition, risk factors have mainly been researched in
isolation. Only few maps and models on protective or
risk factors of dementia are available [1012]. e life-
course model of Livingston, etal. [10] shows potentially
modifiable and non-modifiable risk factors of demen-
tia. It states that 40% of dementia is attributable to 12
potentially modifiable factors over the life course: from
early life, midlife to later life. ey note, however, that
their model does not include other potentially rele-
vant risk factors, such as diet and sleep. e bio-social
model of Spector, Orrell [11] disaggregates psychoso-
cial and biological processes with the aim of under-
standing the inter-relationship between these two and
distinguishing modifiable and non-modifiable factors.
Additionally, their model includes interventions with
potential benefits, although environmental factors are
neglected. All models show the multicausality of Alz-
heimer’s disease, but are not considered comprehen-
sive. Similarly, the model by Uleman etal. (2020) on
Alzheimer’s disease is also an incomplete representa-
tion of reality, missing the environmental and psycho-
logical factors. Together, these models offer important
and detailed insights on the relationships between the
factors, but they do not allow to capture the whole
picture of the multifactorial nature of pathogenesis
of dementia. Hence, in this study we aimed at apply-
ing the most comprehensive approach at the onset of
the disease by developing a causal loop diagram (CLD)
that a) identifies factors related to cognitive decline and
the onset of dementia, b) structures them by different
domains and c) reflects on and visualizes the links and
interactions between these factors.
is work is part of the SHARED study (Social Health
And Reserve in the Dementia patient journey), an inter-
national project funded by the EU Joint Programme –
Neurodegenerative Disease Research (JPND) that focuses
on the interaction between social health, cognitive and
biological factors on dementia using quantitative analy-
ses as well as performing qualitative studies to reveal
additional relevant social factors and relations with cog-
nitive reserve and function [13].
Methods
We deliberately decided on a methodological approach
that combines a comprehensive search of the literature
and a qualitative, participatory research method inte-
grating the knowledge of interdisciplinary experts. It
consists of three sequential and integrated steps: (1) a
systematic literature review; (2) a Group Model Build-
ing (GMB) session; (3) a structured iterative discussion
process (Fig.1).
Step 1: Systematic Literature Review
A systematic literature search of systematic reviews and
meta-analyses was conducted in five databases (Medline,
PsychINFO, CINAHL Complete, Cochrane Database of
Systematic Reviews and Epistemonikos); see Additional
file1. 1. Search strategy. is search provided a compre-
hensive synthesis of factors associated with cognitive
Fig. 1 Illustration of the applied methodical process (Step 1 – Step 3)
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Seifertetal. BMC Geriatrics (2022) 22:507
function in the context of dementia. Articles were eligible
if they reported either on empirical research on the influ-
ence (positive and/or negative) of one single factor or a
combination of factors on cognitive decline or dementia.
Only systematic reviews and meta-analyses were included.
e search was limited to human studies, English lan-
guage, journals and periodicals and time period 1.01.2009
– 1.08.2019. Most of the systematic reviews and meta-
analyses we included, covered studies from a wide time
range but mostly focusing on work published in the last
decade. e exclusion criteria were: non-English articles,
studies about pharmacological interventions (for example
drug tests), non-human studies (for example animal test-
ing), studies on other diseases (for example with no or a
weak link to dementia or about reverse causality).
e search was performed by six reviewers and was
based on two consecutive steps: (1) a title and abstract
screening and (2) a full-text screening. In the first step
articles where independently screened by two review-
ers. Any discrepancies were resolved by consensus with a
third reviewer. Secondly, all six reviewers independently
reviewed potentially relevant articles in full text. Refer-
ence lists of included studies were manually searched for
additional relevant studies. All selected publications were
uploaded into PRIMARY Excel Workbook for System-
atic Reviews for the screening process [14]. A PRISMA
flow diagram [15] was used to summarize study selection
(Additional file1. 2. Flowchart). e inter-rater reliability
of the eligibility criteria (exclusion/inclusion) was checked
using Fleiss Kappa test – a chance-corrected measure of
agreement between more than two reviewers. e agree-
ment reached 0.91, indicating an almost perfect agree-
ment [16].
Clusters for data extraction were developed in two
steps by the six reviewers who did the screening of the
literature and who were therefore familiar with the con-
tent of the data. First, the extraction of the data was car-
ried out deductively with an a priori designed system of
clusters based on already existing clusters in the litera-
ture for cognitive related disease [17], e.g [18, 19]. and
secondly, inductively modified based on the emerging
results as the process of the full-text review progressed.
e extracted data was then summarized in a prepared
data charting form containing title, author(s), country,
year, type of review, number of included studies, type of
diagnosis/health status, age range of study participants,
key findings, comments and seven clusters of factors: (1)
demographic, (2) socioeconomic, (3) lifestyle, (4) social
health, (5) psychological, (6) environmental and (7) phys-
ical. Factors reported in the articles were also categorized
whether their influence was “protective”, “increased risk”,
“no risk”, “unclear” or “no influence”. e results of the lit-
erature search were used as input to the GMB session.
Step 2: Group Model Building (GMB)
GMB is a participatory method for involving experts
in developing models, such as a causal loop diagram
(CLD), a theoretical model or a knowledge map. e
result contains the consensus of the experts on the
basis of a collective decision [2022]. GMB is based
on system dynamics, a methodology to support deci-
sion making in a variety of complex domains. System
dynamics has been successfully applied on a variety of
topics related to health, such as chronic diseases, sub-
stance abuse epidemiology or health care capacity and
delivery [23, 24]. Within the SHARED project, GMB
was used to elicit and to structure knowledge from an
interdisciplinary group of experts and to combine this
knowledge with results of the systematic literature
review into a CLD.
A GMB session with 18 experts from different pro-
fessional disciplines was conducted over two days in
Bremen (Germany). Two experts participated via skype.
e session was led by an experienced GMB-facilitator
and member of the SHARED consortium (ER). All par-
ticipants were members of the SHARED consortium
and/or the INTERDEM (early and timely INTERven-
tions in DEMentia) platform (a pan-European network
of dementia researchers). e group consisted of experts
in psychology (n = 5), public health/ health services and
nursing research (n = 4), medicine (n = 4), epidemiol-
ogy (n = 3), and social science (n = 2). e experts were
from e Netherlands (n = 5), Poland (n = 5), Germany
(n = 4), Australia (n = 2), UK (n = 1) and Italy (n = 1). e
process of GMB started with defining the core variable
of the CLD, in this case “cognitive functioning”. Based on
this, the participants collected, discussed and prioritised
factors influencing the core variable and built a prelimi-
nary CLD model. On the second day factors identified
in the systematic literature review (see Step 1) were pre-
sented to the group. e factors were discussed, priori-
tised and integrated into the CLD. Factors were grouped
into thematic clusters. Clusters were initially deducted
from pre-existing clusters used by e.g. Uleman, et al.
[12], Kinderman [17], Korczyn, Halperin [25], which we
then inductively modified based on our data and in an
iterative process (Step 3). Of the seven categories iden-
tified in step 1, 6 clusters were formed. e clusters (1)
demographic, and (2) socioeconomic were combined
in one cluster “demographic factors”. e connection
between the factors (arrows) based either on expert’s
knowledge of the GMB participants or on results of the
literature review. For building the model in our GMB we
used Vensim DSS, version 8.0.0 [26], a special System
Dynamics software.
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Step 3: Iterative structured discussion
After the GMB session an iterative process, consist-
ing of three feedback rounds, was initiated: first, a
slightly edited version of the CLD produced dur-
ing the session was sent to the SHARED consor-
tium members for feedback. The feedback suggested
adjustments at the level of the factors as well as at
the level of clusters. It also induced changes to the
relationships between factors. Based on the feed-
back a revised CLD was sent again to the SHARED
consortium members and discussed during an online
meeting. The revised CLD was sent to the SHARED
consortium members for final approval. For better
visualisation we transferred the CLD from Vensim to
the software Kumu Inc [26].
Results
e resulting CLD of step 1–3 comprises 73 factors
(Fig.2) that presumably directly or indirectly affect cog-
nitive functioning. ey have been grouped into six clus-
ters (Fig.2).
Fig. 2 Causal loop diagram of responsible factors in the development and trajectory of dementia. To see higher resolution of this causal loop
diagram, go to https:// kumu. io/ ImkeB remen/ causal‑ loop‑ diagr am‑ of‑ facto rs‑ assoc iated‑ with‑ demen tia
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e physical cluster (blue, top right) is made up of 23
factors. Two factors (vascular pathology and cerebrovas-
cular disease) show a high number of relationships to
other factors, suggesting an important role for cognitive
functioning and dementia. e physical cluster has con-
nections with all other clusters.
e social health cluster (green, bottom right) com-
prises a total of 21 factors. Most of the relationships
between factors happen within the cluster. Outwards,
most relationships are to the psychological cluster, fol-
lowed by the physical cluster. e factor social engage-
ment seems to influence numerous other factors and is
at the same time influenced by many factors itself. e
cluster is closely linked to the physical and psychological
cluster, there are no connections to the other clusters.
irteen factors form the psychological cluster (yellow,
bottom left). Within this cluster the factors emotional
wellbeing, level of stress, psychological resilience, cop-
ing behaviour, and self-efficacy seem to be influenced by
several factors from other clusters. e cluster is closely
connected to the physical and social health cluster; there
are hardly any connections to the other clusters.
e environmental cluster (red, top left) comprises
eight factors. ese factors seem to be closely related to
factors from the physical cluster (i.e. cancer, microbiome,
vascular pathology, cerebral vascular disease, COPD). In
addition, there are links to the psychological cluster, e.g.,
there is a positive influence of sun exposure or green space
exposure on emotional wellbeing which in turn is associ-
ated with cognitive functioning. e cluster is only con-
nected to the physical, psychological and demographic
cluster.
Five factors (purple) are grouped together as the demo-
graphic cluster in the top left part of the CLD. Most rela-
tionships are within the cluster. Only a few factors have
links with other clusters. e factors education, profes-
sion and income are connected with all the clusters. e
cluster is connected to all other clusters, with the excep-
tion of the social health cluster.
e cluster of lifestyle factors (orange, top left) is the
smallest of the six thematic fields. It consists of only three
factors (level of physical activity, healthy diet patterns,
substance abuse (overuse of alcohol/ (passive) smoking/
use of drugs). e factors level of physical activity and
healthy diet patterns are closely related to some demo-
graphic and physical factors, e.g. high-level income, higher
level of education, obesity, and cerebrovascular disease.
e cluster is connected to the physical, psychological
and demographic cluster.
In total 57 factors of the CLD were identified in the sys-
tematic literature review. Further, 16 additional factors,
mostly of the social health cluster, were identified during
the GMB session and the feedback rounds (Additional
file1. 3. Clusters and related factors of the model). With
the exception of the factor brain reserve (part of the phys-
ical cluster), all factors added by the experts are part of
the psychological cluster (coping behaviour, emotional
wellbeing, personality traits, psychological resilience,
self-efficacy and social awareness) and the social health
cluster (autonomy, cognitive reserve, dignity, experience
of negative life events, norms and values towards help-
seeking/adherence, positive life events, quality of care/
welfare facilities, reciprocity (reciprocity is defined as a
dynamic characteristic of individual social ties. It refers
to the extent to which exchanges or transactions are even
or reciprocal [27]) and stigma).
Discussion
e objective of this research was to create an informed
and structured overview over the multitude of factors
influencing cognitive function at the onset and trajec-
tory of dementia and their interrelationships. Our CLD
reflects the results of an extensive literature review, a
two-days-workshop using group model building with an
interdisciplinary group of experts, followed by an itera-
tive development by a larger group of researchers.
We structured the factors into six clusters. Even though
it is visible that the clusters and their factors are inter-
related, most of the relationships exist within their own
clusters. e physical cluster comprises 23 factors, the
highest number of all clusters. is is not surprising,
since research on physical (bio-medical) factors have
long dominated the research and discourse on cognitive
decline [11]. All factors from this cluster were identi-
fied through the literature, while none was added by the
experts. Which also indicates that a lot of research has
already been done in this area. In contrast, in the social
health cluster nine of the 21 factors were identified by the
experts during the GMB session. is may in part result
from the composition of the group in which experts for
social health were well represented.
Interrelationships betweenfactors
Our CLD displays (possible) interrelationships between
factors. Our literature search indicated a great variability
in the intensity of the various relationships that have been
investigated. Especially in the non-medical fields and of
the (inter-)relationship between biological and psycho-
logical and social domains, more research is needed to
provide evidence for these interrelationships. With the
help of the CLD new hypotheses can be formulated. To
illustrate this, we use the example of stigma. e role of
stigma in cognitive decline could be investigated by ana-
lysing its relationship with social isolation, loneliness,
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Seifertetal. BMC Geriatrics (2022) 22:507
social interaction and ultimately cognitive functioning
(see Fig.3). As depicted in Fig.3, stigma is not directly
connected with cognitive functioning but rather via
mediating factors. Social engagement is leading directly
and social isolation via social interaction indirectly to
cognitive functioning.
Strengths andlimitations
To our knowledge this is the first study creating a com-
prehensive visualization of the factors influencing cog-
nitive functioning in dementia. A strength of the CLD
is the combination of methods that led to its develop-
ment. It consists of an extensive review of the literature,
a two-day-GMB session with a multidisciplinary group
of experts followed by structured discussions within the
group of experts. It should be noted that the review is
based only on articles from 2009–2019. However, we do
not expect to have missed relevant factors as a major part
of articles on this topic has been written during this time
span. Also, relevant factors detected before 2009 most
likely would have been picked up by the literature in the
years after.
e restriction of English articles can have an impact
on the diversity of the population. Most of the articles
were conducted and based on data from western socie-
ties which limits the generalisability. We also limited our
search to databases that are commonly used in the field
of dementia research.
A limitation might be the unequal representation of
disciplines by experts, which could have translated into
results. ere were more experts with a background in
social health, which might explain why social factors may
have competed in numbers with other clusters. However,
this may highlight a specific gap that has so far not been
visible in empirical research. e results of the system-
atic literature review (which were presented in the GMB
session as a basis for discussion) provided a synthesis of
factors associated with cognitive function in the context
of dementia but were not stratified by the strength of
evidence of each causative link. e arrows in the model
neither show the size of the association nor if the associa-
tion is positive or negative.
Another challenge was the choice of an optimal level of
aggregation of the factors given the heterogeneity of clus-
ters. While we focused at acquiring maximal consistency,
certain factors remain a challenge, as they can be further
identified in more detail (e.g., healthy diet patterns or
level of physical activity).
Another limitation of the results might be not con-
sidering cumulative effects of factors or weighting the
contribution of factors to cognitive decline. Further, the
arrows in the model do not reflect the strength of evi-
dence for the connections between the different factors.
Fig. 3 Illustrative example: Stigma and its relationship with other factors
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Seifertetal. BMC Geriatrics (2022) 22:507
Our CLD inrelation toother models
Our CLD is an attempt to visualize a wide array of fac-
tors influencing cognitive decline and their interrela-
tions. Hou, etal. [28] developed a model to predict the
risk of dementia, however missed to depict the (inter-)
relationship between the factors. e prominent model
by Livingston, etal. [10] focusses on a group of selected,
modifiable factors impacting cognitive decline over the
life course. Uleman, etal. [12] also used a GMB approach
for the development of a CLD model, but with the main
focus on Alzheimer’s disease. Uleman et al.’s model is
based exclusively on expert knowledge whereas our
model combines expert knowledge with the result of
a comprehensive literature review. Uleman et al. con-
ducted a network analysis as well as analyses of feedback
loops. Both models reflect the complexity of Alzheimer’s
and dementia respectively.
In the light of the existing models, our CLD is an
attempt to capture the bigger picture, such as the trajec-
tory from healthy cognition, cognitive decline to demen-
tia in general. Moreover, the developed CLD aggregates
the two-level knowledge – literature-based evidence and
expert knowledge discussed and gathered as a whole.
Conclusions andoutlook
is study aimed at creating a structured visualization
of the multitude of factors influencing cognitive func-
tioning at the onset and trajectory of dementia and
their interrelationships. e result was a highly complex
CLD. It can be used to formulate hypotheses of possible
pathways and to support a theory based on empirical
research. In the wider SHARED project, the CLD will
support structuring the analyses of data on interrela-
tionships of factors collected from more than 40 inter-
national cohort studies. e results of these analyses will
be fed into a new version of the CLD that presents path-
ways and indicates targets for preventive interventions
at the individual and the population level. ese inter-
ventions should then be evaluated in further research.
In this future work it would be valuable to integrate the
life experience of persons living with dementia in the
research process.
Supplementary Information
The online version contains supplementary material available at https:// doi.
org/ 10. 1186/ s12877‑ 022‑ 02955‑2.
Additional le1. (1. Search strategy. 2. Flowchart. 3. Clusters and related
factors of the model).
Acknowledgements
Not applicable
Author contributions
IS, HW, MLB, ML, MP designed figure 1 and the model in figure 2. IS took
the lead in writing the manuscript. All authors discussed the results and
commented on the manuscript. The authors read and approved the final
manuscript.
Funding
Open Access funding enabled and organized by Projekt DEAL. The Federal
Ministry of Education and Research (BMBF) (grantnumber: 01ED1905),
National Centre for Research and Development (NCBR) (grantnumber:
JPND/06/2020) and the EU Joint Programme – Neurodegenerative Disease
Research (JPND) (grantnumber: HESOCARE‑329–109) provide the fundings
for this study. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript.
Availability of data and materials
The data that support the findings of this study are available from the cor‑
responding author (Imke Seifert) but restrictions apply to the availability of
these data, which were used under license for the current study, and so are
not publicly available. Data are however available from the authors upon
reasonable request and with permission of the corresponding author (Imke
Seifert).
Declarations
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Author details
1 Department for Health Services Research, Institute of Public Health and Nurs‑
ing Research (IPP), Health Sciences Bremen, University of Bremen, Grazer
Straße 4 , 28359 Bremen, Germany. 2 Department for Health Care Research,
Institute of Public Health and Nursing Research (IPP), Health Sciences Bremen,
University of Bremen, Bremen, Germany. 3 Department of Psychiatry, Wroclaw
Medical University, Wroclaw, Poland. 4 Methodology Department, Univer‑
sity of Nijmegen, Nijmegen, The Netherlands. 5 Faculty of Medical Sciences,
Radboud University Medical Center, Nijmegen, The Netherlands. 6 Department
of Geriatric Medicine, Radboud University Medical Center, Nijmegen, The
Netherlands.
Received: 29 November 2021 Accepted: 15 March 2022
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... SHARED involves several studies with the aim to unravel the interplay between social health and biological and psychological factors. Studies include the development of a conceptual framework for social health, epidemiological studies (41,42), a systematic review on factors influencing cognitive health (17), a Group Model Building (GMB) study (43), a current study to identify social health measures and an ongoing qualitative study. The conceptual framework was iteratively developed by the interdisciplinary Social Health Stream of SHARED, consisting of a team of 11 experts, and discussed with the whole consortium. ...
... But does it work like that? We explore the feasibility, meaning the applicability, of the conceptual framework through its use in the following studies of the SHARED project: the review of epidemiological studies (17), the epidemiological associations between social health and cognitive functioning in the SHARED data bases (41,42) and a Group Model Building (GMB) (43). ...
Article
Full-text available
Objective The recognition of dementia as a multifactorial disorder encourages the exploration of new pathways to understand its origins. Social health might play a role in cognitive decline and dementia, but conceptual clarity is lacking and this hinders investigation of associations and mechanisms. The objective is to develop a conceptual framework for social health to advance conceptual clarity in future studies. Process We use the following steps: underpinning for concept advancement, concept advancement by the development of a conceptual model, and exploration of its potential feasibility. An iterative consensus-based process was used within the international multidisciplinary SHARED project. Conceptual framework Underpinning of the concept drew from a synthesis of theoretical, conceptual and epidemiological work, and resulted in a definition of social health as wellbeing that relies on capacities both of the individual and the social environment. Consequently, domains in the conceptual framework are on both the individual (e.g., social participation) and the social environmental levels (e.g., social network). We hypothesize that social health acts as a driver for use of cognitive reserve which can then slow cognitive impairment or maintain cognitive functioning. The feasibility of the conceptual framework is demonstrated in its practical use in identifying and structuring of social health markers within the SHARED project. Discussion The conceptual framework provides guidance for future research and facilitates identification of modifiable risk and protective factors, which may in turn shape new avenues for preventive interventions. We highlight the paradigm of social health in dementia as a priority for dementia research.
... This disease affects more than 57 million people worldwide [4], with over 10 million new cases diagnosed each year [5]. Individuals impacted by the syndrome might experience a wide range of stigma and discrimination [6], which is typically related to a general misunderstanding of the disease. Therefore, dementia education, awareness and intervention are vital. ...
Article
Full-text available
Introduction Dementia awareness is a key priority of medical and nursing pre-registration education. The ‘dementia friends’ programme is an internationally recognised and accredited dementia awareness workshop that is led by a trained facilitator. While this programme has been associated with positive outcomes, few studies have examined how medical and nursing students apply their learning in practice after the workshop. The aim of his study was to explore how nursing and medical students apply the dementia friend’s programme into practice when caring for people living with dementia. Methods Seven focus-group interviews were conducted with 36 nursing students and 14 medical students at one university in Northern Ireland (n = 50), following ‘the dementia friends programme. Interview guides were co-designed alongside people living with dementia. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis. Ethical approval was granted for this study. Results Four themes emerged: ‘reframing dementia’, which highlighted how the education had enabled students to actively empower and support people living with dementia in practice; ‘dementia friendly design’, which focused on how students had modified their clinical environments when providing care for people living with dementia, ‘creative communication’, which considered how students had used their education to adapt their verbal and non-verbal communication with people living with dementia and ‘realities of advanced dementia’ which contemplated how students believed their dementia education could be improved within their current curriculum. Discussion The Dementia Friends programme has actively supported nursing and medical students to improve the lives of people with dementia in their care through environmental adaptions and creative approaches to communication. This study provides an evidence base that supports the provision of ‘a dementia friends programme to healthcare professional students. The study also highlights how this education can actively influence how nursing and medical students support people living with dementia in their practice in the months and years after education.
... Cognitive capability, the capacity to undertake the mental tasks of daily living, is an important aspect of healthy ageing [1][2][3]. Numerous factors across the life course can affect cognitive capability and decline [4][5][6][7]. Most research has focused on biological and medical correlates [8]. ...
Article
Full-text available
Introduction: In this study we examine whether social health markers measured at baseline are associated with differences in cognitive capability and in the rate of cognitive decline over an 11-to-18-year period among older adults and compare results across studies. Methods: We applied an integrated data analysis approach to 16,858 participants (mean age 65 years; 56% female) from the National Survey for Health and Development (NSHD), the English Longitudinal Study of Aging (ELSA), the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), and the Rotterdam Study. We used multilevel models to examine social health in relation to cognitive capability and the rate of cognitive decline. Results: Pooled estimates show distinct relationships between markers of social health and cognitive domains e.g., a large network size (≥6 people vs none) was associated with higher executive function (0.17 SD[95%CI:0.0, 0.34], I2=27%) but not with memory (0.08 SD[95%CI: -0.02, 0.18], I2=19%). We also observed pooled associations between being married or cohabiting, having a large network size and participating in social activities with slower decline in cognitive capability, however estimates were close to zero e.g., 0.01SD/year [95%CI: 0.01 to 0.02] I2=19% for marital status and executive function. There were clear study-specific differences: results for average processing speed were the most homogenous and results for average memory were the most heterogenous. Conclusion: Overall, markers of good social health have a positive association with cognitive capability. However, we found differential associations between specific markers of social health and cognitive domains and differences between studies. These findings highlight the importance of examining between study differences and considering context specificity of findings in developing and deploying any interventions.
... Our findings add to the knowledge base that until now has been confirmed to single pathways [8,14]. To the best of our knowledge, in geriatric medicine, CLDs have only been developed in the field of cognition [18,64]. In their CLD paper on Alzheimers's disease, Uleman et al. also conducted network analysis and feedback loop analysis to rank the importance of variables and further analyze their CLD [18]. ...
Article
Full-text available
Orthostatic hypotension (OH) is an established and common cardiovascular risk factor for falls. An in-depth understanding of the various interacting pathophysiological pathways contributing to OH-related falls is essential to guide improvements in diagnostic and treatment opportunities. We applied systems thinking to multidisciplinary map out causal mechanisms and risk factors. For this, we used group model building (GMB) to develop a causal loop diagram (CLD). The GMB was based on the input of experts from multiple domains related to OH and falls and all proposed mechanisms were supported by scientific literature. Our CLD is a conceptual representation of factors involved in OH-related falls, and their interrelatedness. Network analysis and feedback loops were applied to analyze and interpret the CLD, and quantitatively summarize the function and relative importance of the variables. Our CLD contains 50 variables distributed over three intrinsic domains (cerebral, cardiovascular, and musculoskeletal), and an extrinsic domain (e.g., medications). Between the variables, 181 connections and 65 feedback loops were identified. Decreased cerebral blood flow, low blood pressure, impaired baroreflex activity, and physical inactivity were identified as key factors involved in OH-related falls, based on their high centralities. Our CLD reflects the multifactorial pathophysiology of OH-related falls. It enables us to identify key elements, suggesting their potential for new diagnostic and treatment approaches in fall prevention. The interactive online CLD renders it suitable for both research and educational purposes and this CLD is the first step in the development of a computational model for simulating the effects of risk factors on falls.
... These aspects are so intertwined and codependent that it is difficult to address them separately, to understand how SH impacts cognitive function. 29 To our knowledge, our findings are the first to show that having a good overall SH (combining interactional and structural aspects) in late life is associated with attenuated age-related cognitive decline, independent of socioeconomic and health-related factors. Although good SH in late life could reflect beneficial SH throughout life, a hypothesis we are unable to test with the current data, our findings tentatively suggest that promoting SH in late life may constitute one strategy to forestall the progression to cognitive impairment. ...
Article
Objective: Individual aspects of social health (SH; e.g. network, engagement, support) have been linked to cognitive health. However, their combined effect, and the role of the structural properties of the brain (brain reserve, BR) remain unclear. We investigated the interplay of SH and BR on cognitive change in older adults. Methods: Within the Swedish National study on Aging and Care-Kungsholmen, 368 dementia-free adults aged ≥60 years with baseline brain magnetic resonance imaging were followed over 12 years to assess cognitive change. A measure of global cognition was computed at each of the five waves of assessment by averaging domain-specific Z-scores for episodic memory, perceptual speed, semantic memory, letter and category fluency. An SH composite score was computed at baseline by combining leisure activities and social network. BR was proxied by total brain tissue volume (TBTV). Linear mixed models (adjusted for sociodemographic, vascular, and genetic factors) were used to estimate cognitive trajectories in relation to SH, TBTV. Interaction analysis and stratification were used to examine the interplay between SH and TBTV. Results: Moderate-good SH (n=245; vs. poor; β-slope=0.01 [95% CI 0.002, 0.02]; p=0.018) and moderate-to-large TBTV (n=245; vs. small; β-slope=0.03 [95% CI 0.02, 0.04]; p<0.001) were separately associated with slower cognitive decline. In stratified analysis, moderate-good SH was associated with higher cognitive levels (but not change) only in participants with moderate-to-large TBTV (β-intercept=0.21 [95%CI 0.06; 0.37], p<0.01; interaction SH*TBTV p<0.05). Interpretation: Our findings highlight the interplay between social health and brain reserve that likely unfolds throughout the entire life course to shape old-age cognitive outcomes. This article is protected by copyright. All rights reserved.
... The feasibility of the conceptual framework was demonstrated by its guidance in the identification of social health markers in the SHARED project. This includes the study on mapping of factors influencing cognitive function at the onset of dementia (Seifert I, 2022), an ongoing review on the identification of social health measures, epidemiological studies on associations between social health markers and cognitive decline and dementia and qualitative studies to probe additional relevant social factors. The feasibility of the hypothesis and conceptual framework in the SHJARED project indicates its potential for other social health related dementia studies. ...
Preprint
Dementia is a syndrome where the origins are not fully understood, and we have no cure. New thinking through exploration of paradigms beyond biological approaches has scope to improve knowledge about this complex condition. We aim to explore the role of social health in cognitive decline and the onset of dementia. We performed a scoping and a systematic review of the literature, hypothesizing that social health acts as a driver for stimulating the use of cognitive reserve. The review yielded theoretical pathways and evidence for the association between neurobiological and social health markers. However, lack of conceptual clarity on social health hinders its articulation and associated inclusion of social health markers in epidemiological studies. We therefore apply concept advancement of social health. We developed a conceptual framework, and we present a first testing of our overarching hypothesis. This framework proved to effectively guide the identification of social health markers in our epidemiological data bases. This promotes the identification of modifiable risk factors, which may in turn shape new avenues for preventive interventions.
Article
Full-text available
Numerous previous studies have shown the effectiveness of music therapy in enhancing cognitive functions in patients with dementia. Despite this, robust evidence in this field, especially concerning the comparison of different music therapy types, is lacking. Therefore, randomized controlled trials (RCTs) focusing on music therapy and cognitive functions in dementia patients, termed by “music” AND “dementia” OR “Alzheimer’s disease” AND “cognitive”, were identified from primary electronic databases to conduct this network meta-analysis (NMA). The primary outcome focused on the impact on cognitive functions, and the secondary outcome was the comparison of dropout rates between the intervention groups and the usual care control groups. Standardized mean difference (SMD) values and the corresponding 95% confidence intervals (CIs) were computed for effect evaluation. This study protocol has been registered in IPLASY (INPLASY202430082). A total of 14 RCTs with 1056 participants were enrolled, examining interventions including Active Music Therapy (AMT), Active Music Therapy with Singing (AMT + Sing), Rhythmic Music Therapy (RMT), Listening to Music (LtM), and Singing (Sing). The results indicated that RMT, AMT + Sing, and AMT all significantly improve cognitive functions in dementia patients, of which the SMD were 0.76 (95% CI = 0.32–1.21), 0.79 (95% CI = 0.03–1.49), and 0.57 (0.18–0.96), respectively. Compared with the control group (usual care), no music therapy type was associated with an increased dropout risk. In conclusion, music therapy can improve cognitive functions in patients with dementia without increasing the risk of dropout, particularly RMT, AMT + Sing, and AMT.
Article
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Alzheimer’s disease (AD) is a complex, multicausal disorder involving several spatiotemporal scales and scientific domains. While many studies focus on specific parts of this system, the complexity of AD is rarely studied as a whole. In this work, we apply systems thinking to map out known causal mechanisms and risk factors ranging from intracellular to psychosocial scales in sporadic AD. We report on the first systemic causal loop diagram (CLD) for AD, which is the result of an interdisciplinary group model building (GMB) process. The GMB was based on the input of experts from multiple domains and all proposed mechanisms were supported by scientific literature. The CLD elucidates interaction and feedback mechanisms that contribute to cognitive decline from midlife onward as described by the experts. As an immediate outcome, we observed several non-trivial reinforcing feedback loops involving factors at multiple spatial scales, which are rarely considered within the same theoretical framework. We also observed high centrality for modifiable risk factors such as social relationships and physical activity, which suggests they may be promising leverage points for interventions. This illustrates how a CLD from an interdisciplinary GMB process may lead to novel insights into complex disorders. Furthermore, the CLD is the first step in the development of a computational model for simulating the effects of risk factors on AD.
Article
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Background: Because the pattern of illnesses changes in an aging population and many people manage to live well with chronic diseases, a group of health care professionals recently proposed reformulating the static WHO definition of health towards a dynamic one based on the ability to physically, mentally and socially adapt and self-manage. This paper is the result of a collaborative action of the INTERDEM Social Health Taskforce to operationalize this new health concept for people with dementia, more specifically the social domain, and to formulate directions for research and practice to promote social health in dementia. Method: Based on the expertise of the Social Health Taskforce members (N = 54) three groups were formed that worked on operationalizing the three social health dimensions described by Huber et al.: (1) capacity to fulfil potential and obligations; (2) ability to manage life with some degree of independence; (3) participation in social activities. For each dimension also influencing factors, effective interventions and knowledge gaps were inventoried. After a consensus meeting, the operationalizations of the dimensions were reviewed by the European Working Group of People with Dementia (EWGPWD). Results: The social health dimensions could be well operationalized for people with dementia and are assessed as very relevant according to the Social Health Taskforce and EWGPWD. Personal (e.g. sense of coherence, competencies), disease-related (e.g. severity of cognitive impairments, comorbidity), social (support from network, stigma) and environmental factors (e.g. enabling design, accessibility) that can influence the person with dementia's social health and many interventions promoting social health were identified. Conclusion: A consensus-based operationalization of social health in dementia is proposed, and factors that can influence, and interventions that improve, social health in dementia identified. Recommendations are made for research and practice.
Article
Full-text available
Background Dementia risk reduction is a major and growing public health priority. While certain modifiable risk factors for dementia have been identified, there remains a substantial proportion of unexplained risk. There is evidence that environmental risk factors may explain some of this risk. Thus, we present the first comprehensive systematic review of environmental risk factors for dementia. Methods We searched the PubMed and Web of Science databases from their inception to January 2016, bibliographies of review articles, and articles related to publically available environmental data. Articles were included if they examined the association between an environmental risk factor and dementia. Studies with another outcome (for example, cognition), a physiological measure of the exposure, case studies, animal studies, and studies of nutrition were excluded. Data were extracted from individual studies which were, in turn, appraised for methodological quality. The strength and consistency of the overall evidence for each risk factor identified was assessed. Results We screened 4784 studies and included 60 in the review. Risk factors were considered in six categories: air quality, toxic heavy metals, other metals, other trace elements, occupational-related exposures, and miscellaneous environmental factors. Few studies took a life course approach. There is at least moderate evidence implicating the following risk factors: air pollution; aluminium; silicon; selenium; pesticides; vitamin D deficiency; and electric and magnetic fields. Conclusions Studies varied widely in size and quality and therefore we must be circumspect in our conclusions. Nevertheless, this extensive review suggests that future research could focus on a short list of environmental risk factors for dementia. Furthermore, further robust, longitudinal studies with repeated measures of environmental exposures are required to confirm these associations.
Article
The notion of social health (Huber et al. , 2011) as applied to dementia care research was introduced to redress the balance of empirical studies that tended to focus on biomedical, cognitive, and functional status in dementia (Vernooij-Dassen and Jeon, 2016). The introduction of social health has followed the zeitgeist of campaigners for a better life for those living with dementia, with initiatives to improve the social images of dementia (Alzheimers.org, 2017). Examples from social research in dementia to examine friendships and the social environments of people with dementia exist (Medeiros et al. , 2012), but introduction of the paradigm of social health in dementia (Vernooij-Dassen and Jeon, 2016) has harnessed a growing research agenda (de Vugt and Dröes, 2017). This paradigm provides an umbrella concept to study how social aspects influence the dynamic balance between opportunities and limitations in dementia. Social health goes beyond the neuropathology of dementia, to understand how people, their social networks and wider society with its norms, interact with the condition (Vernooij-Dassen and Jeon, 2016). It is not far removed from the ideas of Tom Kitwood, the pioneer of person-centered dementia care, who noted that “personhood is a standing or status that is bestowed upon one human being, by others, in the context of relationship and social being” (Kitwood, 1997). The INTERDEM (Early detection and timely INTERvention in DEMentia, www.interdem.org ) psychosocial research agenda aspired to improve knowledge about social inclusion and reciprocal relationships for people with dementia (Moniz-Cook et al ., 2011). The concept of social health (Vernooij-Dassen and Jeon, 2016) with its dimensions for dementia research (Dröes et al. , 2017) has begun to develop this knowledge-base.
Article
Background Information from well-established dementia risk models can guide targeted intervention to prevent dementia, in addition to the main purpose of quantifying the probability of developing dementia in the future. Methods We conducted a systematic review of published studies on existing dementia risk models. The models were assessed by sensitivity, specificity and area under the curve (AUC) from receiver operating characteristic analysis. Results Of 8462 studies reviewed, 61 articles describing dementia risk models were identified, with the majority of the articles modelling late life risk (n=39), followed by those modelling prediction of mild cognitive impairment to Alzheimer’s disease (n=15), mid-life risk (n=4) and patients with diabetes (n=3). Age, sex, education, Mini Mental State Examination, the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological assessment battery, Alzheimer’s Disease Assessment Scale-cognitive subscale, body mass index, alcohol intake and genetic variables are the most common predictors included in the models. Most risk models had moderate-to-high predictive ability (AUC>0.70). The highest AUC value (0.932) was produced from a risk model developed for patients with mild cognitive impairment. Conclusion The predictive ability of existing dementia risk models is acceptable. Population-specific dementia risk models are necessary for populations and subpopulations with different characteristics.
Article
Alzheimer’s disease (AD) is the leading cause of dementia, and because the primary risk factor for AD is old age, the prevalence of the disease is increasing dramatically with ageing populations worldwide. Even in high-income countries, the cost of medical care and associated societal burdens of dementia threaten to become overwhelming as more people live into old age. In view of the lack of progress in developing a cure for AD and the rapidly increasing costs of dementia, policy makers and governments have a powerful incentive to provide more resources to develop AD therapeutics. The Lancet Neurology Commission was formed with the overarching aim to provide information and expert recommendations to policy makers and political leaders about the growing problem of AD and related dementias of ageing. The past two decades have seen remarkable improvements in the quality of care for patients with AD, with a research-driven shift to more personalised and integrated team-oriented care. Epidemiological and genetic studies have identifi ed many factors that increase the risk of AD. Prevention studies have highlighted the possibility of targeting risk and protective factors to delay onset, with the promise of reducing the overall prevalence of dementia. However, no treatment is yet available to halt or reverse the underlying pathology of established AD. Indeed, an eff ective therapy for AD is perhaps the greatest unmet need facing modern medicine. Basic biomedical research has provided insights into the causes and pathogenesis of AD and other neurodegenerative diseases, but improved understanding of disease mechanisms will be needed to develop safe and eff ective disease-modifying treatments. Nonetheless, several drugs are currently in late phases of clinical development. The Commission considered a range of challenges that need to be addressed to reduce the burden of dementia, and these challenges are discussed in detail in the main sections of our report: health economics (section 1), epidemiology (section 2), prevention (section 3), genetics (section 4), biology (section 5), diagnosis (section 6), treatment (sections 7, 8), care (section 9), and ethics (section 10). In panel 1 we summarise the key fi ndings of the Commission, with recommendations about how patient care and related research—from basic to clinical— in AD and other dementias should be organised in the future. A concerted eff ort to tackle dementia is needed, with a substantial overall increase in government and private investment in the care of patients and the search for AD therapeutics. Europe is well placed to take the world lead, in partnership with international organisations, to develop new approaches to prevent or cure AD and other dementias and to provide models of compassionate care for patients. As the cost of care increases, funds must not be shunted from basic research, clinical research, and drug-discovery programmes. In fact, a substantial increase in long-term funding for multidisciplinary research programmes is absolutely essential to reduce the burden of individual suff ering and the enormous societal cost of AD. Only targeted increases in research investment will provide any hope of fi nding a cure for AD or developing strategies to delay the onset or slow the progression of the disease.
Article
Background The aetiology of Alzheimer's disease (AD) is believed to involve environmental exposure and genetic susceptibility. The aim of our present systematic review and meta-analysis was to roundly evaluate the association between AD and its modifiable risk factors. Methods We systematically searched PubMed and the Cochrane Database of Systematic Reviews from inception to July 2014, and the references of retrieved relevant articles. We included prospective cohort studies and retrospective case–control studies. Results 16 906 articles were identified of which 323 with 93 factors met the inclusion criteria for meta-analysis. Among factors with relatively strong evidence (pooled population >5000) in our meta-analysis, we found grade I evidence for 4 medical exposures (oestrogen, statin, antihypertensive medications and non-steroidal anti-inflammatory drugs therapy) as well as 4 dietary exposures (folate, vitamin E/C and coffee) as protective factors of AD. We found grade I evidence showing that one biochemical exposure (hyperhomocysteine) and one psychological condition (depression) significantly increase risk of developing AD. We also found grade I evidence indicative of complex roles of pre-existing disease (frailty, carotid atherosclerosis, hypertension, low diastolic blood pressure, type 2 diabetes mellitus (Asian population) increasing risk whereas history of arthritis, heart disease, metabolic syndrome and cancer decreasing risk) and lifestyle (low education, high body mass index (BMI) in mid-life and low BMI increasing the risk whereas cognitive activity, current smoking (Western population), light-to-moderate drinking, stress, high BMI in late-life decreasing the risk) in influencing AD risk. We identified no evidence suggestive of significant association with occupational exposures. Conclusions Effective interventions in diet, medications, biochemical exposures, psychological condition, pre-existing disease and lifestyle may decrease new incidence of AD.
Article
This article discusses the issue of making group model building interventions more of a science than an art by outlining a number of requirements of a research program. Important elements that are discussed are the various goals of group model building interventions and the components and scripts of an intervention. Then the problem of theory development is discussed, together with a number of hypotheses which the authors suggest need more investigation. The article also discusses issues related to the selection of an appropriate research design, as well as a number of thorny measurement problems.