Abstract
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Purpose
While capability and opportunity factors in dementia prevention have been extensively studied, the motivational mechanisms that translate these resources into behavior remain relatively underexplored. This study examined the mediating effect of self-efficacy on the relationships between instrumental activities of daily living (IADL), social networks, and dementia-prevention behaviors among community-dwelling older adults, guided by the capability, opportunity, motivation-behavior (COM-B) theoretical framework.
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Methods
A cross-sectional study was conducted with 205 community-dwelling adults aged 65 years and older residing in Gyeongsangnam Province, South Korea. Data were collected between July and September 2024 using validated instruments, including the Korean Instrumental Activities of Daily Living, Social Network Measurement Scale, General Self-Efficacy Scale, and Korean Health Behavior for Dementia Prevention Scale. Mediation analysis was performed using Hayes’ PROCESS macro (model 4) with bootstrap resampling (5,000 iterations) to estimate indirect effects, while controlling for demographic and health-related covariates.
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Results
Self-efficacy significantly mediated both the IADL–dementia-prevention behavior relationship (indirect effect, −0.33; 95% confidence interval [CI], −0.61 to −0.12) and the social network–dementia-prevention behavior relationship (indirect effect, 0.08; 95% CI, 0.002 to 0.19). The mediation models explained 40.7% and 48.5% of the variance in dementia-prevention behaviors, respectively. Bootstrap CIs confirmed significant partial mediation effects in both pathways.
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Conclusion
These findings provide empirical support for the COM-B model’s theoretical proposition that motivation serves as a critical bridge linking capability and opportunity factors to actual behavior. Nursing interventions should therefore integrate self-efficacy–enhancement strategies alongside traditional capability-building and opportunity-provision approaches to maximize the effectiveness of dementia-prevention programs for older adults.
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Key Words: Aged; Dementia; Health behavior; Motivation; Self-efficacy
INTRODUCTION
South Korea is undergoing unprecedented demographic change. As of 2025, adults aged 65 years and older comprise approximately 10.58 million individuals, accounting for 20.0% of the total population, with this proportion projected to increase to 24.5% by 2030 [
1]. This rapid population aging is accompanied by a substantial rise in dementia prevalence. According to the 2025 National Dementia Epidemiological Survey, approximately 970,000 older adults (9.2% of those aged 65 years and older) are currently living with dementia, with projections exceeding 1 million by 2026 and 2 million by 2044 [
2]. Notably, the 2020 Lancet Commission reported that approximately 40% of dementia cases could be prevented or delayed through behavioral interventions targeting modifiable risk factors [
3]. Key dementia-prevention behaviors include regular physical exercise, social engagement, cognitive stimulation, cardiovascular health management (such as blood pressure control, weight maintenance, and diabetes management), smoking cessation, and healthy dietary practices [
3]. Together, these converging demographic and epidemiological trends, combined with substantial prevention potential, underscore the urgent need to understand and promote effective dementia-prevention strategies.
At the individual level, dementia progressively undermines functional independence, erodes personal identity, and diminishes quality of life [
3]. Families experience substantial caregiving burdens, with approximately 45.8% of family caregivers reporting significant physical, emotional, and financial strain [
4]. At the societal level, economic costs are both considerable and escalating: total dementia-related management costs reached approximately 20 trillion won in 2025 and are projected to increase to 63 trillion won by 2040 [
1,
4]. These profound individual, familial, and societal consequences collectively highlight the critical importance of effective dementia-prevention strategies.
Despite considerable advances in dementia-prevention knowledge and widespread public awareness campaigns, translating knowledge into sustained behavioral practice remains challenging. Among older adults in South Korea, engagement in dementia-prevention behaviors remains suboptimal, with average scores of only 56 to 63 points out of 100 and preventive activities practiced just 1 to 2 days per week [
5]. Several factors contribute to this persistent knowledge-behavior gap. First, traditional health education approaches have primarily emphasized information delivery, operating under the flawed assumption that knowledge directly translates into behavior change, an assumption consistently refuted by health behavior literature [
6,
7]. Second, older adults face multiple concurrent barriers, including physical limitations, demands related to chronic disease management, and diminished psychological resources, all of which may impede preventive action despite adequate knowledge [
5,
7]. Third, dementia prevention requires sustained engagement across multiple complex behavioral domains, including cognitive stimulation, physical activity, social participation, and lifestyle modification, making long-term adherence particularly difficult in the absence of strong motivational foundations [
8,
9]. This substantial gap between awareness and action highlights the limitations of traditional prevention approaches that prioritize information dissemination without adequately addressing the psychological mechanisms necessary for translating knowledge into sustained behavioral practice [
6,
7].
The capability, opportunity, motivation-behavior (COM-B) model provides a comprehensive theoretical framework for understanding the complex mechanisms underlying health behavior change [
7]. It proposes that behavior emerges from the dynamic interaction of three essential components: capability, defined as the physical and psychological capacity to perform behaviors; opportunity, referring to the environmental and social conditions that enable those behaviors; and motivation, encompassing the psychological processes that energize and direct behavior. While previous dementia-prevention research has extensively examined capability factors, such as knowledge, cognitive function, and physical health, as well as opportunity factors, including social support and resource availability, the motivational component remains significantly underexplored. In particular, the psychological mechanisms through which capabilities and opportunities are translated into sustained behavioral engagement have received limited empirical attention. Beyond dementia prevention, the COM-B model has been widely applied across diverse health behaviors, demonstrating the value of explicitly specifying capability, opportunity, and motivation when designing behavior change interventions [
7]. However, most COM-B–based applications have focused on single behavioral targets and have rarely examined multidomain, long-term dementia-prevention lifestyles in community-dwelling older adults, underscoring the need for the present study.
Among motivational factors, including outcome expectations, attitudes, and intentions, self-efficacy is particularly critical for understanding health behavior change in older adults. Self-efficacy, defined as individuals’ confidence in their capacity to execute specific behaviors [
10], differs from other motivational constructs by emphasizing perceived capability rather than behavioral desirability or intention [
6]. Meta-analytic evidence indicates that self-efficacy is among the strongest predictors of both health behavior initiation and long-term maintenance, especially for behaviors requiring sustained effort and self-regulation, such as dementia prevention [
11].
Self-efficacy assumes heightened importance in older adult populations due to age-specific challenges that uniquely threaten behavioral confidence. According to Bandura social cognitive theory, self-efficacy develops through mastery experiences, vicarious learning, social persuasion, and the interpretation of physiological states [
10]. Older adults encounter distinctive obstacles across all four sources. Functional declines, including reduced strength, slower processing speed, and diminished sensory acuity, undermine mastery experiences; smaller social networks and declining peer health limit opportunities for vicarious learning; ageist attitudes from family members and healthcare providers may weaken social encouragement; and chronic physical symptoms are often misinterpreted as evidence of incapacity [
3,
9]. Although self-efficacy facilitates behavior change across the lifespan, it assumes disproportionate importance in later life [
8,
10]. Younger adults’ relatively stable functioning and broader social networks allow other motivational factors, such as outcome expectations and intentions, to more readily drive behavior. In contrast, for older adults facing functional decline, social network contraction, and age-related messaging, self-efficacy becomes the critical psychological resource determining whether knowledge and opportunities are translated into actual preventive behavior [
7,
8,
11].
Two key factors that may influence dementia-prevention behaviors through self-efficacy pathways are instrumental activities of daily living (IADL) and social networks. Within the COM-B framework, IADL represents a central capability factor, reflecting the physical and cognitive capacities required for independent functioning. In COM-B, capability is interpreted in relation to the target behavior, and dementia-prevention behaviors require sufficient functional capacity to plan, initiate, and sustain daily activities. IADL tasks, including financial management, medication adherence, transportation use, and household management, require the integration of multiple cognitive and executive functions [
12,
13]. From the perspective of Bandura social cognitive theory, mastery experiences constitute the most powerful source of self-efficacy [
10]. Successful performance of IADL tasks may therefore serve as such experiences, providing older adults with tangible evidence of their continued competence. While IADL reflects functional capacity as a capability construct, self-efficacy represents motivational confidence to enact target behaviors. Previous research has demonstrated significant positive associations between IADL and self-efficacy [
14]. This conceptualization of functional independence as a capability factor is further supported by COM-B–informed health behavior research, in which activities of daily living, including instrumental domains, have been mapped onto capability as indicators of the physical and psychological capacities influencing behavioral engagement in older adults [
15].
Social networks represent the opportunity component within this framework, providing the environmental and social conditions that enable behavior change [
3,
7,
16,
17]. Social connections enhance self-efficacy through multiple mechanisms, including vicarious learning, such as observing peers’ successful behaviors; verbal persuasion, through encouragement from network members; and emotional support, which reduces stress and enhances positive affect [
6,
9,
10]. This relationship is bidirectional. Higher self-efficacy can motivate older adults to maintain social connections despite age-related barriers, such as mobility limitations and hearing loss, whereas lower self-efficacy may contribute to social withdrawal, initiating a cycle that erodes both social resources and behavioral confidence [
6,
10]. Empirical evidence supports this reciprocal pathway, with prior studies demonstrating significant associations between social networks and self-efficacy, as well as self-efficacy’s mediating role in social support-health behavior relationships [
8,
9].
Despite this strong theoretical foundation, few studies have explicitly examined the mediating role of self-efficacy in the pathways linking IADL and social networks to dementia-prevention behaviors. Most existing research has examined these factors in isolation or has focused primarily on their direct effects, thereby overlooking potentially critical motivational mechanisms that translate available resources into sustained behavioral engagement. Clarifying these pathways is essential, as it may inform the design of more effective dementia-prevention programs and guide more strategic allocation of intervention resources.
The COM-B model’s proposition that capability and opportunity factors influence behavior through motivational mechanisms provides an appropriate framework for examining these relationships. However, few studies have empirically tested this pathway within the context of dementia prevention, and many current prevention programs continue to emphasize capability-building or opportunity enhancement while giving limited attention to motivational processes. Identifying the mediating role of self-efficacy may therefore support the development of more comprehensive interventions that integrate all three COM-B components, addressing persistent gaps in both theory and practice.
Therefore, this study aimed to examine self-efficacy as a motivational mediator in the relationships between functional capability, specifically IADL, social opportunity, represented by social networks, and dementia-prevention behaviors among community-dwelling older adults. We hypothesized that greater independence in IADL would be associated with higher self-efficacy, which would, in turn, predict stronger engagement in dementia-prevention behaviors. We further hypothesized that stronger social networks would be associated with higher self-efficacy, which would subsequently predict greater engagement in dementia-prevention behaviors. By testing these mediational pathways, this study sought to provide empirical support for the theoretical propositions of the COM-B model and to inform the development of more effective, theoretically grounded dementia-prevention interventions that simultaneously address motivational, capability, and opportunity factors.
METHODS
1. Study Design
This descriptive cross-sectional study examined the mediating effects of self-efficacy on the relationships among IADL, social networks, and dementia-prevention behaviors in community-dwelling older adults, using the COM-B theoretical framework. The study is reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines.
2. Study Participants
Participants were community-dwelling adults aged 65 years and older residing in Changwon City, Gyeongsangnam Province, South Korea, who understood the purpose of the study and provided informed consent. Convenience sampling was employed. Inclusion criteria were as follows: (1) aged 65 years or older with the ability to read, comprehend, and communicate, and (2) scoring within the “no cognitive impairment” range on the Korean Mini-Mental State Examination–2 Short Form (K-MMSE-2: SF) [
18]. Exclusion criteria included (1) current treatment for physician-diagnosed psychiatric disorders and (2) a diagnosis of dementia.
The required sample size was calculated using G*Power 3.1.9.7 [
19] for mediation analysis, following sample size guidelines for mediation models proposed by Sim et al. [
20]. Parameters included a significance level of α=0.05, a medium effect size (f²=0.15) consistent with prior self-efficacy and COM-B–based health behavior research [
8,
11], and high statistical power (1–β=0.95) to minimize type II error in detecting indirect effects. The model included 14 potential predictor variables, comprising six demographic variables, four health-related variables, and four study variables. This yielded a minimum sample size of 194 participants.
However, after preliminary analyses and consideration of multicollinearity, the final mediation models included only six control variables: age, education level, living arrangements, monthly income, chronic disease status, and subjective health status. These variables demonstrated significant associations with dementia-prevention behaviors in bivariate analyses. To account for the characteristics of the older adult population and the complexity of the mediation analysis, the target sample size was set at 224 participants, allowing for an anticipated dropout rate of 15%. According to Fritz and MacKinnon [
21], this sample size is sufficient to detect medium-sized indirect effects with 80% statistical power in mediation analyses using bootstrapping methods.
Initial cognitive screening was conducted with 230 older adults. Two participants were excluded due to cognitive impairment based on K-MMSE-2: SF results, yielding 228 eligible participants. Of these, 23 were excluded because of incomplete responses, corresponding to a dropout rate of 10.1%. The final analytic sample therefore comprised 205 participants, exceeding the minimum sample size required for robust mediation analysis.
3. Measurements
1) General and health-related characteristics
General and health-related characteristics were assessed using questionnaire items adapted from previous studies [
22]. General characteristics included seven items: sex, age, education level, religion, living arrangement, economic activity status, and monthly income level. Health-related characteristics included the presence of chronic disease(s) and subjective health status.
2) Dementia-prevention behaviors
Dementia-prevention behaviors were measured using the Korean Health Behavior for Dementia Prevention Scale (K-HBDP), developed by Kim et al. [
23]. Permission to use the K-HBDP was obtained from the original developer via e-mail prior to data collection. The scale comprises 23 items across five subdomains: intellectual-social activity (seven items), health management (six items), lifestyle (five items), smoking and drinking (two items), and dietary habits (three items). Items are rated on a 4-point Likert scale ranging from “hardly ever” (1) to “always” (4), with higher scores indicating stronger engagement in dementia-prevention behaviors. Cronbach’s α was .90 in the original development study [
23] and .89 in the present study.
3) Instrumental activities of daily living
IADL were assessed using the Korean Instrumental Activities of Daily Living (K-IADL) scale, adapted by Won et al. [
24] from the Self-Maintaining and IADL scale originally developed by Lawton and Brody [
12]. Permission to use the K-IADL was obtained from the original developer via e-mail prior to the study. The scale consists of 10 items rated on a 3-point Likert-type scale: “completely independent” (1), “needs some help” (2), and “needs complete help” (3). Higher scores indicate greater dependence in IADL. Cronbach’s α was .94 in the validation study of Won et al. [
24] and .89 in the present study.
4) Social networks
Social networks were measured using the functional characteristics of natural relationships subscale from the Social Network Measurement Scale developed by Jung [
25] for older adults, based on earlier foundational research [
26]. Permission to use this scale was obtained from the original developer via e-mail prior to data collection. The scale comprises 12 items across four subdomains: emotional relationships, informational relationships, instrumental relationships, and social activity relationships, each consisting of three items. Items are rated on a 5-point Likert scale ranging from “not at all true” (1) to “very true” (5), with higher scores indicating stronger social networks. Cronbach’s α was .91 in Jung’s development study [
25] and .92 in the present study.
5) Self-efficacy
Self-efficacy was measured using the Self-efficacy Scale adapted for Korean populations by Oh [
27] from the General Self-Efficacy Scale (GSES) originally developed by Sherer et al. [
28]. Permission to use the GSES for research purposes was obtained from one of the original developers via e-mail prior to data collection. The scale consists of 17 items designed to assess general self-efficacy expectations without reference to specific behavioral domains. Items are rated on a 5-point Likert scale ranging from “not at all true” (1) to “very true” (5), with higher scores indicating stronger self-efficacy. Cronbach’s α was .71 in the original study of Sherer et al. [
28], .80 in Oh’s validation study [
27], and .72 in the present study. All measurement instruments were used with permission from the original developers or copyright holders.
Data were collected from July 2 to September 18, 2024, using structured questionnaires administered by the researcher at community locations, including traditional markets, beauty salons, and senior centers, within the city. After obtaining permission from site managers, the researcher approached older adults, explained the study purpose, and screened potential participants for eligibility (age ≥65 years, community-dwelling status, ability to communicate in South Korean, and no prior diagnosis of dementia). Individuals who met the eligibility criteria and agreed to participate received a more detailed explanation of the study and provided written informed consent. Questionnaires were completed either through self-administration or with assistance from the researcher; for participants with visual or literacy difficulties, items were read aloud and responses were recorded by the researcher. Participation was entirely voluntary, and participants were informed that they could skip any question or withdraw from the study at any time without penalty. Each survey required approximately 30 to 40 minutes to complete. Of the 228 questionnaires returned (response rate: 100%), 205 were included in the final analysis after excluding incomplete responses.
5. Ethical Considerations
This study was approved by the Institutional Review Board of Gyeongsang National University (IRB No. GIRB-A24-NY-0062). The study purpose, procedures, voluntary nature of participation, and confidentiality safeguards were clearly explained to all participants. Only individuals who provided written informed consent were included in the study. All collected data were anonymized and securely stored for three years before disposal.
6. Data Analysis
Data were analyzed using IBM SPSS ver. 28.0 (IBM Corp., Armonk, NY, USA).
p-values of less than 0.05 were considered significant. Descriptive statistics, including frequencies, percentages, means, and standard deviations, were calculated to describe participants’ general and health-related characteristics as well as key study variables. Group differences were examined using the independent t-test and one-way analysis of variance, with Scheffé test applied for post hoc comparisons. Associations among IADL, social networks, self-efficacy, and dementia-prevention behaviors were assessed using Pearson correlation coefficients. To examine the mediating effects of self-efficacy in the relationships between IADL and dementia-prevention behaviors, as well as between social networks and dementia-prevention behaviors, Hayes’ SPSS PROCESS macro version 4.2 (model 4) was employed [
29]. This analytical approach was selected because it yields robust estimates of indirect effects through bias-corrected bootstrap 95% confidence intervals (CIs), which are considered more accurate than traditional methods such as the Sobel test [
30]. Bootstrap resampling with 5,000 iterations was conducted to estimate direct and indirect effects and to generate bias-corrected 95% CIs. Mediation effects were considered statistically significant when the 95% CI did not include zero [
29]. Partial mediation was defined as the presence of statistically significant direct and indirect effects, whereas complete mediation was defined as a statistically significant indirect effect in the absence of a significant direct effect. Prior to mediation analysis, key regression assumptions were evaluated. Independence of observations was assessed using the Durbin-Watson statistic. Multicollinearity was examined using variance inflation factors, with values below 10 considered acceptable [
31]. Linearity and homoscedasticity were assessed through inspection of residual plots. All mediation analyses controlled for variables that demonstrated significant associations with dementia-prevention behaviors, including age, education level, living arrangement, monthly income, presence of chronic diseases, and subjective health status. Internal consistency reliability of all measurement instruments was confirmed using Cronbach’s α [
32].
RESULTS
1. General and Health-Related Characteristics of Participants
The final sample comprised 205 community-dwelling older adults, with a mean age of 75.68±6.85 years. Women accounted for 51.2% (n=105) of the sample, while men comprised 48.8% (n=100). By age group, 43.9% (n=90) were aged ≤74 years, 43.4% (n=89) were aged 75 to 84 years, and 12.7% (n=26) were aged ≥85 years. Regarding educational attainment, 29.8% (n=61) had completed elementary school or less, 56.6% (n=116) had completed middle or high school, and 13.7% (n=28) had attained a college-level education or higher. More than half of the participants reported a religious affiliation (58.0%, n=119). Approximately two-thirds of the participants (66.8%, n=137) lived with others, whereas 33.2% (n=68) lived alone. Most participants were not economically active (71.2%, n=146), and 59.5% (n=122) reported monthly household incomes below 1 million KRW (Korean won). Three quarters of the sample (75.1%, n=154) reported having at least one chronic disease. Subjective health status was rated as good by 23.9% (n=49), moderate by 61.0% (n=125), and poor by 15.1% (n=31) (
Table 1).
Significant differences in study variables were observed across demographic and health-related characteristics. IADL dependence differed significantly according to age (F=21.11,
p<.001), education level (F=11.75,
p<.001), living arrangement (t=4.88,
p=.001), economic activity (t=−5.63,
p<.001), monthly income (F=8.33,
p<.001), presence of chronic diseases (t=3.69,
p<.001), and subjective health status (F=26.99,
p<.001). Social networks differed significantly by education level (F=7.28,
p<.001), religion (t=2.41,
p=.017), living arrangement (t=4.30,
p=.002), economic activity (t=3.03,
p=.003), monthly income (F=5.83,
p=.001), chronic disease status (t=−2.76,
p=.006), and subjective health status (F=19.99,
p<.001). Self-efficacy showed significant differences according to education level (F=3.88,
p=.005), economic activity (t=2.91,
p=.004), monthly income (F=4.03,
p=.008), and subjective health status (F=12.14,
p<.001). Dementia-prevention behaviors varied significantly by age (F=5.65,
p=.004), education level (F=8.22,
p<.001), living arrangement (t=4.22,
p=.003), monthly income (F=4.11,
p=.007), presence of chronic diseases (t=−3.02,
p=.003), and subjective health status (F=19.57,
p<.001) (
Table 1).
Prior to the main analyses, normality was evaluated using skewness and kurtosis values. All study variables demonstrated values within acceptable ranges (skewness, −0.28 to 1.98; kurtosis, −0.95 to 6.12), supporting the use of parametric statistical procedures. Mean scores for the study variables indicated generally favorable functional and psychosocial status among participants. IADL dependence was low, with a mean score of 1.19±0.32 on a 3-point scale, reflecting relatively high functional independence. Social networks had a mean score of 3.36±0.84 on a 5-point scale. Among the four subdomains, informational networks demonstrated the highest scores, followed by emotional, instrumental, and social activity networks (data not shown). Self-efficacy averaged 3.59±0.59 on a 5-point scale. Dementia-prevention behaviors had a mean score of 2.80±0.56 on a 4-point scale, corresponding to approximately 70% of the maximum possible score (
Table 2).
Correlation analysis revealed statistically significant associations among all study variables. IADL was negatively correlated with social networks (r=−.42, p<.001), self-efficacy (r=−.39, p<.001), and dementia-prevention behaviors (r=−.41, p<.001), indicating that greater functional independence was associated with stronger social connections, higher self-efficacy, and better engagement in dementia-prevention behaviors. Social networks were positively correlated with self-efficacy (r=.54, p<.001) and dementia-prevention behaviors (r=.62, p<.001). Self-efficacy also demonstrated a significant positive correlation with dementia-prevention behaviors (r=.46, p<.001).
5. Mediating Effects of Self-Efficacy
Before conducting mediation analyses, regression assumptions were examined and met. Durbin-Watson statistics (1.738 for the IADL model and 1.505 for the social networks model) confirmed the independence of observations, and variance inflation factor values ranging from 1.209 to 4.466 indicated the absence of multicollinearity. Inspection of residual plots supported assumptions of linearity and homoscedasticity. The resulting mediation models are illustrated in
Figure 1.
1) Self-efficacy as a mediator between IADL and dementia-prevention behaviors
After controlling for age, education level, living arrangement, monthly income, chronic disease status, and subjective health status, mediation analysis demonstrated that self-efficacy significantly mediated the relationship between IADL and dementia-prevention behaviors (
Figure 1). In the mediator model, IADL significantly predicted self-efficacy (B=−0.29, standard error [SE]=0.25, β=−.93,
p<.001). In the outcome model, both IADL (B=−0.21, SE=0.29, β=−.87,
p=.004) and self-efficacy (B=0.27, SE=0.08, β=.35,
p<.001) were significant predictors of dementia-prevention behaviors. The total effect of IADL on dementia-prevention behaviors was B=−1.20 (95% CI, −1.80 to −0.61), which decreased to a direct effect of B=−0.87 (95% CI, −1.46 to −0.28) after inclusion of self-efficacy in the model. The indirect effect via self-efficacy was statistically significant (B=−0.33; 95% CI, −0.61 to −0.12), indicating partial mediation. This model explained 40.7% of the variance in dementia-prevention behaviors (R²=0.41, F=8.63,
p<.001) (
Table 3).
2) Self-efficacy as a mediator between social networks and dementia-prevention behaviors
Self-efficacy also significantly mediated the relationship between social networks and dementia-prevention behaviors (
Figure 1). Social networks significantly predicted self-efficacy (B=0.47, SE=0.06, β=.47,
p<.001). In the outcome model, both social networks (B=0.42, SE=0.08, β=.54,
p<.001) and self-efficacy (B=0.14, SE=0.08, β=.18,
p=.030) were significant predictors of dementia-prevention behaviors. The total effect of social networks on dementia-prevention behaviors was B=0.63 (95% CI, 0.48 to 0.79), with a direct effect of B=0.54 (95% CI, 0.37 to 0.72) and a significant indirect effect through self-efficacy (B=0.08; 95% CI, 0.002 to 0.19), supporting partial mediation. This model accounted for 48.5% of the variance in dementia-prevention behaviors (R²=0.49, F=11.88,
p<.001) (
Table 4).
Bootstrap analysis using 5,000 resamples confirmed the statistical significance of both indirect effects, as neither confidence interval included zero, providing robust support for the mediating role of self-efficacy in both pathways.
DISCUSSION
This study examined how self-efficacy functions as a motivational mediator between functional capability, represented by IADL, social opportunity, represented by social networks, and dementia-prevention behaviors among community-dwelling older adults within the COM-B theoretical framework. The findings provide empirical evidence that self-efficacy operates as a critical psychological mechanism that transforms capability and opportunity factors into sustained health behaviors. In doing so, the results extend beyond traditional approaches that emphasize skill acquisition or environmental resource enhancement alone.
The central finding of this study—that self-efficacy partially mediates both the IADL–dementia-prevention behavior relationship and the social network–dementia-prevention behavior relationship—supports the COM-B model’s theoretical proposition that motivation bridges the gap between capability and opportunity factors and actual behavior [
7,
16]. This finding extends previous COM-B research in several important respects [
33]. While earlier qualitative studies identified motivational barriers to health behaviors in dementia-related contexts [
34], these investigations primarily mapped barriers and facilitators onto COM-B domains without empirically testing the mechanisms through which capability and opportunity exert their effects. By contrast, the present quantitative analysis provides direct empirical evidence for the specific motivational pathways through which these factors influence behavior.
The observation of partial, rather than complete, mediation in both pathways carries important theoretical and practical implications. Partial mediation indicates that IADL and social networks influence dementia-prevention behaviors through two complementary mechanisms: a direct pathway reflecting habitual, structural, or contextual determinants, and an indirect pathway operating through enhanced self-efficacy beliefs. This pattern aligns with Bandura social cognitive theory [
10], which emphasizes that although self-efficacy is a powerful determinant of behavior, it functions alongside other cognitive, environmental, and contextual influences rather than acting as the sole mediator.
Differences in the magnitude of mediation effects across the two pathways provide additional insight into how capability and opportunity factors generate motivation. The stronger mediation observed in the IADL pathway, compared with the social networks pathway, may reflect fundamental differences in the sources of self-efficacy. IADL performance constitutes direct mastery experience, identified by Bandura as the most influential source of self-efficacy, because it provides individuals with immediate and personal evidence of their functional competence [
10,
12,
13]. Successfully managing finances, medications, and transportation demonstrates concrete proficiency in complex cognitive and executive tasks that closely resemble those required for dementia-prevention behaviors [
12,
13]. In contrast, social networks influence self-efficacy through more indirect mechanisms, including vicarious learning, verbal persuasion, and emotional support [
6,
10], which may exert a less immediate impact on behavior-specific confidence. These findings suggest that interventions aimed at strengthening functional independence may have particularly strong motivational effects on dementia-prevention behaviors.
Notably, the present findings parallel those reported by Chen et al. [
33], who demonstrated that physical activity motivation partially mediated the relationships between frailty and physical activity, as well as between physical and social support and physical activity, in older adults with subjective cognitive decline. In both studies, partial rather than complete mediation was observed, indicating that capability and opportunity factors retain direct effects on behavior even after accounting for motivational processes [
33]. However, the present study extends Chen et al.’s work in three key ways [
33]. First, whereas Chen et al. [
33] focused on physical activity as a single behavioral domain, this study examined a comprehensive set of dementia-prevention behaviors encompassing cognitive stimulation, social engagement, and lifestyle modification, reflecting the multidimensional nature of dementia prevention [
3]. Second, Chen et al. [
33] operationalized motivation as domain-specific physical activity motivation, whereas this study examined self-efficacy as a more fundamental motivational construct that may generalize across multiple behavioral domains [
10,
11]. Third, the present study focused on cognitively intact, community-dwelling older adults, demonstrating that these motivational pathways operate in primary prevention contexts, not only among higher-risk populations with existing cognitive decline.
Beyond the mediation pathways, the observed correlations among study variables warrant further consideration. The negative correlations between IADL dependence and social networks, self-efficacy, and dementia-prevention behaviors reflect a cascading process in which functional limitations undermine social engagement, erode confidence, and reduce preventive action. Although similar associations have been reported in previous research, viewing these relationships through the COM-B framework provides additional interpretive depth [
7,
12]. Rather than representing isolated bivariate associations, these correlations illustrate interconnected pathways through which functional capability shapes health behavior engagement.
A particularly noteworthy finding is the strong positive correlation between social networks and self-efficacy, which exceeded the correlation between IADL and self-efficacy despite the weaker mediation effect observed in the social networks pathway. This apparent discrepancy can be understood by distinguishing between correlation strength and mediation strength. Social networks may be strongly associated with general self-efficacy through their roles in emotional support, social identity, and reinforcement of self-worth [
6,
9,
17]. However, their influence on behavior-specific efficacy beliefs, and consequently on dementia-prevention behaviors, may be more limited unless explicitly targeted. This pattern suggests that while social networks broadly support psychological well-being, additional intervention components may be required to translate social resources into concrete preventive actions. This interpretation is consistent with longitudinal evidence indicating that restricted social networks are associated with an increased risk of incident dementia [
35].
Finally, the significant influence of education across all study variables, consistent with previous research, underscores education’s role as a foundational determinant that simultaneously shapes multiple COM-B components [
8,
22]. Higher educational attainment enhances psychological capability through improved health literacy and information-processing skills, expands opportunity through broader social networks and greater access to resources, and strengthens motivation through an increased sense of control and self-efficacy [
3,
6,
8,
22]. This multi-pathway influence suggests that educational disparities in dementia risk operate through complex, interconnected mechanisms rather than through single, linear causal pathways [
3].
These findings have important implications for the development of dementia-prevention programs and nursing practice. Traditional interventions have often emphasized capability enhancement, through education and skill training, or opportunity improvement, through resource provision and social programming. The present results indicate that such approaches may be insufficient if the motivational component is not adequately addressed. Effective interventions should therefore integrate self-efficacy–enhancement strategies alongside improvements in capability and opportunity [
7].
For older adults with good functional independence and strong social networks but low self-efficacy, interventions may focus on guided mastery experiences in which individuals practice dementia-prevention behaviors with gradually reduced support, allowing confidence to develop through repeated successful performance [
6,
10]. For those with functional limitations or weaker social networks, interventions should concurrently address these structural barriers while building self-efficacy through alternative pathways, such as vicarious learning opportunities or verbal persuasion delivered by credible sources [
6,
10].
From a nursing practice perspective, these findings underscore the importance of systematically assessing and addressing self-efficacy in addition to traditional capability and opportunity factors. Nurses working with older adults should implement interventions that not only provide information and resources but also actively cultivate confidence in patients’ ability to carry out dementia-prevention behaviors. The strong associations between social networks, self-efficacy, and prevention behaviors further suggest that family-centered approaches and peer-support programs represent essential components of comprehensive dementia-prevention initiatives [
8,
9,
17].
This study has several limitations that warrant consideration. The cross-sectional design precludes causal inference regarding the directionality of relationships among the study variables. Dementia-related knowledge and depressive symptoms were not measured, which may have resulted in residual confounding. The reliance on self-report measures introduces the possibility of response bias, potentially affecting the accuracy of the findings. In addition, convenience sampling from a single metropolitan area may limit the generalizability of the results to populations in different geographic or sociocultural contexts. Future longitudinal studies are needed to establish temporal relationships and to examine how these mediation pathways evolve over time.
CONCLUSION
This study provides empirical evidence that self-efficacy functions as a crucial motivational mediator in the relationships among functional capabilities, social opportunities, and dementia-prevention behaviors in older adults. These findings extend the theoretical understanding of the COM-B model while offering practical guidance for the development of dementia-prevention interventions. Rather than focusing exclusively on enhancing capabilities and opportunities, effective programs should prioritize motivational enhancement through self-efficacy–building strategies. By addressing the psychological mechanisms that translate resources into action, such interventions may promote more sustainable behavioral change and ultimately reduce dementia risk in aging populations.
-
CONFLICTS OF INTEREST
The authors declared no conflict of interest.
-
AUTHORSHIP
Study conception and/or design acquisition - JYK and HKC; analysis - JYK and HKC; interpretation of the data - JYK and HKC; and drafting or critical revision of the manuscript for important intellectual content - JYK and HKC.
-
FUNDING
None.
-
ACKNOWLEDGEMENT
This article is a condensed form of the Ji Yoon Kim’s master’s thesis from Gyeongsang National University.
-
DATA AVAILABILITY STATEMENT
The data can be obtained from the corresponding authors.
Figure 1.Mediation models of self-efficacy among instrumental activities of daily living (IADL), social networks, and dementia-prevention behaviors (DPB). Standardized regression coefficients (β) are adjusted for age, education level, living arrangement, monthly income, chronic disease status, and subjective health status. All paths shown are statistically significant (p<.05). The top model represents the IADL–self-efficacy–DPB pathway, and the bottom model represents the social networks–self-efficacy–DPB pathway.
Table 1.General and Health-Related Characteristics and Differences in Study Variables (N=205)
|
Characteristics |
Categories |
n (%) or M±SD |
IADL |
Social networks |
Self-efficacy |
Dementia- prevention behaviors |
|
M±SD, t/F (p) |
|
Sex |
Male |
100 (48.8) |
11.73±2.46 |
40.28±10.25 |
61.53±9.86 |
64.63±12.61 |
|
Female |
105 (51.2) |
11.97±3.75 |
40.29±9.86 |
60.57±10.30 |
64.19±13.38 |
|
|
0.54 (.585) |
0.01 (.997) |
–0.68 (.497) |
–0.24 (.809) |
|
Age (year) |
≤74a
|
90 (43.9) |
10.93±1.98 |
40.37±9.02 |
61.70±9.82 |
63.72±12.99 |
|
75–84b
|
89 (43.4) |
12.08±3.00 |
40.88±10.61 |
61.39±10.05 |
66.81±12.38 |
|
≥85c
|
26 (12.7) |
15.72±5.60 |
36.83±11.90 |
55.72±10.64 |
56.06±12.62 |
|
75.68±6.85 |
21.11 (<.001) |
1.23 (.294) |
2.81 (.062) |
5.65 (.004) |
|
a<b<c |
c<b |
|
Education |
≤Elementarya
|
61 (29.8) |
13.78±4.20 |
36.89±10.66 |
57.79±10.42 |
57.40±13.40 |
|
Middle-High schoolb
|
116 (56.6) |
10.98±2.17 |
40.48±9.37 |
61.20±9.78 |
65.89±12.33 |
|
≥Collegec
|
28 (13.7) |
10.36±0.73 |
47.32±6.61 |
66.75±9.09 |
72.39±9.58 |
|
|
11.75 (<.001) |
7.28 (<.001) |
3.88 (.005) |
8.22 (<.001) |
|
b, c<a |
a<b, c |
a<b, c |
a<b, c |
|
Religion |
Yes |
119 (58.0) |
11.68±3.27 |
41.70±9.71 |
62.21±10.52 |
65.25±13.04 |
|
No |
86 (42.0) |
12.09±3.06 |
38.33±10.18 |
59.42±9.25 |
63.23±12.88 |
|
|
–0.91 (.361) |
2.41 (.017) |
1.97 (.500) |
1.10 (.273) |
|
Living arrangement |
Alone |
68 (33.2) |
12.87±3.73 |
36.50±10.68 |
58.24±9.98 |
59.68±13.85 |
|
With others |
137 (66.8) |
10.93±1.87 |
42.61±8.68 |
62.03±10.04 |
67.54±11.28 |
|
|
4.88 (.001) |
4.30 (.002) |
2.20 (.070) |
4.22 (.003) |
|
Economic activity |
Yes |
58 (28.3) |
10.55±1.01 |
43.60±9.97 |
64.31±10.57 |
66.59±13.87 |
|
No |
146 (71.2) |
12.38±3.59 |
38.97±9.80 |
59.84±9.59 |
63.58±12.59 |
|
|
–5.63 (<.001) |
3.03 (.003) |
2.91 (.004) |
1.49 (.137) |
|
Monthly income (10⁴ KRW) |
≤99a
|
122 (59.5) |
12.70±3.78 |
38.39±10.78 |
59.39±10.26 |
62.50±13.11 |
|
100–299b
|
62 (30.2) |
10.61±1.11 |
42.59±7.86 |
62.72±8.76 |
65.05±12.52 |
|
≥300c
|
21 (10.2) |
10.29±0.56 |
46.76±7.47 |
66.57±10.39 |
71.86±11.26 |
|
|
8.33 (<.001) |
5.83 (.001) |
4.03 (.008) |
4.11 (.007) |
|
b, c<a |
a<b, c |
a<b, c |
a<b, c |
|
Chronic diseases |
Yes |
154 (75.1) |
12.17±3.53 |
39.19±9.93 |
61.08±10.32 |
62.86±13.05 |
|
No |
51 (24.9) |
10.90±1.38 |
43.59±9.66 |
60.90±9.42 |
69.08±11.67 |
|
|
3.69 (<.001) |
–2.76 (.006) |
0.11 (.911) |
–3.02 (.003) |
|
Subjective health |
Gooda
|
49 (23.9) |
11.67±2.83 |
43.55±10.05 |
64.24±10.94 |
69.41±13.42 |
|
Moderateb
|
125 (61.0) |
11.08±2.11 |
41.33±8.88 |
61.61±9.35 |
65.34±11.50 |
|
Poorc
|
31 (15.1) |
15.26±4.81 |
30.90±9.09 |
53.68±7.98 |
52.71±11.17 |
|
|
26.99 (<.001) |
19.99 (<.001) |
12.14 (<.001) |
19.57 (<.001) |
|
a, b<c |
c<a, b |
c<a, b |
c<a, b |
Table 2.Levels of Study Variables (N=205)
|
Variables |
Range |
Min |
Max |
M±SD |
Mean score†
|
|
IADL |
1–30 |
10 |
27 |
11.42±3.18 |
1.19±0.32 |
|
Social networks |
12–60 |
12 |
60 |
40.28±10.02 |
3.36±0.84 |
|
Self-efficacy |
17–85 |
39 |
85 |
61.04±10.08 |
3.59±0.59 |
|
Dementia-prevention behaviors |
23–92 |
34 |
89 |
62.40±12.98 |
2.80±0.56 |
Table 3.Mediating Effect of Self-Efficacy between IADL and Dementia-Prevention Behaviors (N=205)
|
Variables |
B |
SE |
β |
t |
p
|
95% CI |
|
Mediator model (DV: self-efficacy) |
|
|
|
|
|
|
|
IADL |
–0.29 |
0.25 |
–.93 |
–3.68 |
<.001 |
–1.42 to –0.43 |
|
F=4.41, R²=0.26, p<.001 |
|
Outcome model (DV: dementia-prevention behaviors) |
|
|
|
|
|
|
|
IADL |
–0.21 |
0.29 |
–.87 |
–2.92 |
.004 |
–1.46 to –0.28 |
|
Self-efficacy |
0.27 |
0.08 |
.35 |
4.29 |
<.001 |
0.19 to 0.52 |
|
F=8.63, R²=0.41, p<.001 |
|
Effect decomposition |
Effect |
SE |
95% CI |
|
Effect type |
|
|
|
|
Total effect |
–1.20 |
0.30 |
–1.80 to –0.61 |
|
Direct effect |
–0.87 |
0.29 |
–1.46 to –0.28 |
|
Indirect effect |
–0.33 |
0.12 |
–0.61 to –0.12 |
Table 4.Mediating Effect of Self-Efficacy between Social Networks and Dementia-Prevention Behaviors (N=205)
|
Variables |
B |
SE |
β |
t |
p
|
95% CI |
|
Mediator model (DV: self-efficacy) |
|
|
|
|
|
|
|
Social networks |
0.47 |
0.06 |
.47 |
7.00 |
<.001 |
0.34 to 0.61 |
|
F=7.55, R²=0.36, p<.001 |
|
Outcome model (DV: dementia-prevention behaviors) |
|
|
|
|
|
|
Social networks |
0.42 |
0.08 |
.54 |
6.23 |
<.001 |
0.37 to 0.72 |
|
Self-efficacy |
0.14 |
0.08 |
.18 |
2.18 |
.030 |
0.01 to 0.34 |
|
F=11.88, R²=0.49, p<.001 |
|
Effect decomposition |
Effect |
SE |
95% CI |
|
Effect type |
|
|
|
|
Total effect |
0.63 |
0.07 |
0.48 to 0.79 |
|
Direct effect |
0.54 |
0.08 |
0.37 to 0.72 |
|
Indirect effect |
0.08 |
0.04 |
0.002 to 0.19 |
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