Improvement of social frailty is associated with stability of nonparametric characteristics of the rest-activity rhythm and improvement of the usual walking ability in the elderly.

Our study, conducted between April 2022 and January 2024, was aimed at clarifying components of the rest-activity rhythm (RAR) involved in improvement of social frailty state before or after a 3-month multi-component exercise intervention in the elderly. Participants were recruited from the general population in Akita prefecture, Japan. We administered a four-item social frailty screening questionnaire to classify the severity of social frailty in each participant before and after the 3-month intervention. The RAR parameters were measured on an Actiwatch Spectrum Plus device worn by the subjects for 7 continuous days. As the final sample, 65 participants classified into the improved/maintained group (n = 36) or the deteriorated group (n = 29) according to the change in the social frailty classification after the intervention were included in the analysis. The results of a binomial logistic regression analysis showed significantly higher values of interdaily stability (IS) and usual walking speed at the post-test after the intervention. Based on our findings, we propose that stability of the rest-activity rhythm related to synchronization with external stimuli (such as social effect and physical activity) might have clinical impact on improvement of social frailty state in elderly community-dwellers.

Comparative Analysis of Frailty Risk and Associated Factors: Community-Based vs. Open Recruitment Groups.

BACKGROUND: Frailty leads to vulnerability to stress, impaired daily functioning, and an increased need for care. Frailty is considered reversible, and it is crucial to detect the risk of frailty early and investigate factors that may delay its progression. OBJECTIVES: To identify tests that can explain frailty risk and compare the situation of local residents with and without frailty support. METHODS: Participants were recruited in two ways: through public advertisements in Akita City (open recruitment group) and through invites from frailty supporters in their immediate communities (community-based group). We examined the differences in frailty risk and oral, motor, and social functions between the two groups and identified factors associated with frailty risk in both groups. RESULTS: The community-based group exhibited a lower risk of frailty than the open recruitment group despite having more older members on average. Additionally, the community-based group demonstrated better social functioning than the open-recruitment group. Furthermore, factors such as oral diadochokinesis (ODK), one-leg stand test (OLS), and grip strength (GS) showed significant association with frailty risk. CONCLUSION: The ODK, OLS, and GS were identified as factors explaining frailty risk, and Frailty Supporters may reduce the risk of frailty.

Effect of a multicomponent programme based on reality orientation therapy on the physical performance and cognitive function of elderly community-dwellers: a quasi-experimental study.

BACKGROUND: Effects of a multicomponent exercise programme have an impact on the physical, cognitive, and psychological domains in elderly community-dwellers. However, some individuals aged 65 years or more have not shown positive effects after the intervention as reported in similar research. The objective of this quasi-experimental study was to clarify the effectiveness of a multicomponent programme based on reality orientation therapy (ROT) on the physical performance, cognitive ability, and psychological state in the elderly. METHOD: Participants were recruited from the general public in 20 areas of Akita Prefecture, Japan, and they took part in each exercise programme for 90 min a day, once every 2 weeks, for 3 months, according to the group classification using cluster randomization into 20 cohorts in Akita. Physical, cognitive, and geriatric depression assessments were performed at baseline and after the 3-month intervention in both the ROT-based intervention group and the control group. RESULT: The final samples for analysis consisted of 31 participants in the control group and 30 participants in the intervention group. The results of the statistical analysis comparing the two groups showed that the 5-repetition sit-to-stand test was performed significantly faster (P < 0.05) and that the results of the word list memory (WM) test and the Symbol Digit Substitution Task also had significantly improved (P < 0.05) after the intervention in both groups. The WM score did not show an interactive effect between the group and time factors, but it had a significant main effect on time in both groups (P < 0.05). CONCLUSION: The results of our quasi-experimental study indicated that the multicomponent programme based on the ROT would be as effective as the original multicomponent programme combined with aerobic exercise and cognitive tasks, as highlighted in the WM.

[An examination of the performance efficiency among dementia community support coordinators in Akita Prefecture].

AIM: To consider what is necessary to ensure the efficient performance of dementia community support coordinators. METHODS: In Akita Prefecture, we conducted a simple questionnaire survey of dementia community support coordinators in 25 municipalities to clarify the current status of their activities and examine what needs to be done to develop their projects more efficiently. RESULTS: It became clear that residents were not aware of the existence of these coordinators, underscoring the need to publicize their existence and activities. The lack of tools to improve the public's understanding of social resources for sharing information on building a support system was also demonstrated. In terms of cooperation, it was found that, despite the establishment of cooperation with IPIST and the medical center for dementia, cooperation with dementia support coordinators was insufficient. Furthermore, we confirmed that support coordinators were not very involved in the creation and activities of dementia care paths. CONCLUSIONS: Based on the above findings, we propose five points to support further efficient development. 1. Disseminate information to inform local residents about dementia community support coordinators, 2. Collaborate with dementia support coordinators and the welfare commissioner, 3. Create social resource maps and facilitate their understanding and establish dementia care path activities, 4. Create a work environment where dementia community support coordinators do not have to work concurrently, and 5. Create learning opportunities to improve understanding of the overall dementia policy.

Association between recovery of frailty state and the nonparametric rest-activity rhythm patterns in the elderly community-dwellers: A 6-month follow-up study during Covid-19 pandemic.

Reversibility of frailty in the elderly has been discussed comprehensively and but association between recovery of frail state and rest-activity rhythm (RAR) patterns remains unclear. The aim of the current study was to examine a predictor of RAR patterns at the baseline against change of frail state after the intervention in the elderly community-dwellers. This study was performed during Covid-19 pandemic, at the period from April in 2020 to March in 2022. Participants were publicly recruited from senior's exercise program hosted by Akita city or Yurihonjo city. The revised Japanese version of the Cardiovascular Health Study criteria (revised J-CHS criteria) was used to assess frail state in each participant before and after the 6-month intervention. To measure the nonparametric RAR parameters consisting of interdaily stability (IS), intra-daily variability (IV), relative amplitude (RA) and average physical activity for the most active 10-h span (M10) or for the least active 5-h span (L5) over the average 24-h profile, an Actiwatch Spectrum Plus device was worn on each participant's non-dominant wrist for seven continuous days. The final samples were 75 participants except for persons with uncompleted data, classified into the improved group (n = 12), the maintained group (n = 53) and the deteriorated group (n = 10) according to frail alteration after the six-month intervention. As a result of the multinomial logistic regression analysis with the reference of the maintained group, the improvement of frail state associated with a low value of IS and total night-sleep time at the baseline, and M10 and L5 at the initial time were also able to predict worsening of frail state after the six-months intervention. A result of this follow-up study provides grounds for our proposal that alterations of RAR patterns in the elderly could be observed in association with recovery or worsening of frail state after the intervention. The potential finding, however, warrants further longitudinal investigation.

A Pilot Survey: Oral Function as One of the Risk Factors for Physical Frailty.

BACKGROUND: The aim of this study was to examine the association of the multiple facets of oral, motor, and social functions in community-dwelling older adults, to identify factors that might influence the risk of frailty. METHODS: Of the 82 participants included in the study, 39 (5 males and 34 females) were young-old adults, with an average age of 70.5 ± 2.8 years, and 43 (14 males and 29 females) were old-old adults, with an average age of 78.7 ± 2.9 years. We assessed the risk factors for frailty among oral, motor, and social functions. RESULTS: Statistical analysis showed a significant difference in the oral diadochokinesis between the groups (p = 0.006). According to the Spearman correlation analysis, a significant association was observed with age and oral diadochokinesis (rs = -0.262, p = 0.018), and social support (rs = -0.219, p = 0.049). Moreover, binomial logistic regression analysis revealed a significant association of frailty with the occlusal force (odds ratio, 0.031; 95% confidence interval (95% CI), 0.002-0.430; p = 0.010), General Oral Health Index (odds ratio, 0.930; 95% CI, 0.867-0.999, p = 0.046), and availability of social support (odds ratio, 0.803, 95% CI, 0.690-0.934, p = 0.004). CONCLUSIONS: To prevent frailty at an early stage, assessments of oral functions, and also that of the availability of social support, are important.

The Effect of Deep Micro Vibrotactile Stimulation on Cognitive Function of Mild Cognitive Impairment and Mild Dementia.

Background: The purpose of this study was to clarify the effect of Deep Micro Vibrotactile (DMV) stimulation on the cognitive functions in elderly people with mild cognitive impairment or mild dementia. Methods: A total of 35 participants with dementia from three nursing homes, who had completed treatment with DMV stimulation at 15−40 Hz (hereinafter, 15−40 Hz DMV stimulation) for a month were recruited for this study. The subjects had received continuous 15−40 Hz DMV stimulation for 24 h a day for 1 month. We assessed the effect of the treatment on the cognitive functions (by the word list memory (WM) test, trail making test-part A (TMT-A) and part B (TMT-B), and symbol digit substitution task (SDST)) and physical functions (grip strength (GS) and usual walking speed (UWS)), by comparing the results at the baseline and after the 1-month intervention (DMV stimulation). Results: The results revealed that the performances in the WM test (p < 0.05), TMT-B (p < 0.05), and SDST (p < 0.01) improved significantly after the intervention. Conclusion: Our findings suggest that 15−40 Hz DMV stimulation is might be effective for improving the cognitive functions in elderly people with dementia. Furthermore, our novel findings showed the different effectiveness of the treatment depending on the stage of cognitive impairments.

[Factors influencing changes in daily life due to the state of emergency among older adults living in Akita Prefecture].

The present study is assessed the effects of COVID-19 on the mental and physical function after the declaration of an emergency situation, which included the request that residents refrain from going out, in order to prevent the spread of COVID-19 infection. The investigation was conducted from 2019 to 2020. Our samples consisted of 506 older adults (332 people in 2019 and 174 people in 2020), whose physical, cognitive, depression, and independence in daily and social activities were measured annually. Furthermore, a questionnaire survey (COVID-19 questionnaire) on the impact of the spread of COVID-19 infection on respondents' daily lives (reduction in social interaction, going out, exercise, and sleep time) was conducted among participants in 2020. According to a statistical analysis, the UWS (Usual Walking Speed) was significantly faster in 2020 than it had been in 2019 (p<0.000). However, no significant differences were found in other items. A correlation analysis, revealed a significant association between the reduction in sleep time and GDS-15 (Geriatric Depression Scale) score (r=0.200, p=0.019) and between the COVID-19 questionnaire total score and body mass index (r=0.282, p=0.001).These results suggest that the decline in the physical and mental function might not have been evident in older adults in Akita Prefecture, where the number of infected people is small, although a more detailed long-term follow-up is needed. Even in such areas, there might be a significant relationship between depression and sleep or between changes in daily life due to self-imposed restraint and obesity as an effect of self-imposed restraint among older adults.

Dasatinib plus quercetin attenuates some frailty characteristics in SAMP10 mice.

Senolytics are a class of drugs that selectively remove senescent cells. Dasatinib and quercetin have been discovered, and their combination has shown various anti-ageing effects. The SAMP10 mouse strain is a model of brain ageing. Here, we investigated the effect of combination on frailty characteristics in SAMP10. By comparing SAMP10 with SAMR1 mice as normal ageing controls, we investigated some frailty characteristics. Frailty was assessed at 18-38 weeks of age with a clinical frailty index. Motor and cognitive function of these mice were evaluated using behavioral experiments. SAMP10 mice were divided into vehicle and combination, and these functions and histological changes in the brain hippocampus were investigated. Finally, the in vitro effects of combination on oxidative stress-induced senescent muscle and neuronal cells were investigated. As a result, we found that frailty index was higher in SAMP10 than SAMR1. Motor and cognitive function were worse in SAMP10 than SAMR1. Furthermore, combination therapy improved frailty, motor and cognitive function, and the senescent phenotype of the hippocampus compared with vehicle in SAMP10. In summary, SAMP10 showed more marked frailty characteristics than SAMR1, and dasatinib and quercetin attenuated them in SAMP10. From our results, senolytic therapy might contribute protective effects against frailty.

Person-centered dementia care during COVID-19: a qualitative case study of impact on and collaborations between caregivers.

BACKGROUND: Little is known about the actual impact of COVID-19 on caregivers of older people with dementia and resultant collaborations among them to provide continued person-centered care while undertaking infection control measures. In this study, we explored the impact of providing dementia care during COVID-19 on caregivers involved in dementia care. METHODS: This is an exploratory qualitative case study. The participants were family members living with older people with dementia, care managers, and the medical and long-term care facility staff. Data were collected from 46 caregivers via face-to-face and semi-structured interviews and analyzed using thematic analysis. RESULTS: The interviews identified 22 themes related to the impact of COVID-19 on different positions of the caregivers involved in dementia care and their collaboration, and we categorized them into six categories. The core themes were "re-acknowledgement of care priorities" and "rebuilding of relationships." When caregivers' perceptions were aligned in the decision-making processes regarding care priorities, "reaffirmation of trust" and "strengthening of intimate relationships" emerged as positive changes in their relationships. Furthermore, the differences in the ability of each caregiver to access and select correct and appropriate information about COVID-19, and the extent of infection spread in the region were related to "anxiety during COVID-19 pandemic" and caused a "gap in perception" regarding infection control. CONCLUSIONS: The present study clarified that the process of aligning the perceptions of caregivers to the objectives and priorities of care for older people with dementia during COVID-19 pandemic strengthened the relationships among caregivers. The findings of this study are useful for caregivers involved in person-centered dementia care.

Association between on-road driving performance test and usual walking speed or sustainable attention in the elderly; Preliminary survey.

OBJECTIVE: An increase in older drivers has been widely recognized in Japan; accordingly, screening to prevent traffic accidents is a crucial issue for safe driving. As a preliminary study, we examined the association between on-road driving performance and cognition or physical performance in older individuals. METHODS: The survey was conducted in 2020, and the participants were recruited in Katagami City, Akita, Japan. The Road Test was used to assess on-road driving performance. The physical assessment comprised the usual walking speed (UWS) and grip strength (GS), and the cognitive evaluation consisted of the National Center for Geriatrics and Gerontology Functional Assessment Tool (NCGG-FAT) and the Japanese version of Stroke Drivers' Screening Assessment (J-SDSA). A multiple regression model was also applied to examine the association between on-road driving performance and the physical items or cognitive domains of the NCGG-FAT and the J-SDSA in older individuals. RESULTS: Twenty-one participants (mean age ± standard deviation [SD], 77.0 ± 5.5 years) were included in this study. A correlation analysis showed that the on-road test score was correlated with performances on the UWS (r = 0.53, p = .002), the word list memory (WM) test (r = 0.44, p = .046), the trail-making test-A (TMT-A) (r = -0.44, p = .048), the SDSA dot cancelation (DC) test (r = -0.63, p = .002), and the SDSA squares matrix compass test (SM) (r = 0.54, p = .048). According to a stepwise linear regression, the on-road test score was associated with the UWS (ß = -0.01, p = .003) and the SDSA DC (ß = 4.89, p = .01), with an adjusted R2 = 0.54. CONCLUSIONS: The results of the study suggested that the UWS and sustainable attention might be potential factors influencing on-road driving performance. Our preliminary findings warrant further investigation.

Impact of COVID-19 Pandemic Exacerbation of Depressive Symptoms for Social Frailty from the ORANGE Registry.

BACKGROUND: Recent longitudinal studies have reported proportion of frailty transition in older individuals during the COVID-19 pandemic. Our study aimed at clarifying the impact of social frailty in community-dwelling older adults during the COVID-19 pandemic and at identifying factors that can predict transition to social frailty. METHODS: We performed this study from 2019 (before declaration of the state of emergency over the rising number of COVID-19 cases) to 2020 (after declaration of the emergency). We applied Makizako's social frail index to our study subjects at the baseline and classified into robust, social prefrailty, and social frailty groups. Multiple logistic regression analysis was performed using robust, social prefrailty, or social frailty status as dependent variable. RESULTS: Analysis by the Kruskal-Wallis test revealed significant differences in the score on the GDS-15 among the robust, social prefrailty, and social frailty groups (p < 0.05). Furthermore, multiple regression analysis identified a significant association between the social frailty status and the score on GDS-15 (odds ratio, 1.57; 95% confidence interval (95% CI), 1.15-2.13; p = 0.001). CONCLUSION: The increase in the rate of transition of elderly individuals to the social frailty group could have been related to the implementation of the stay-at-home order as part of the countermeasures for COVID-19. Furthermore, the increased prevalence of depressive symptoms associated with the stay-at-home order could also have influenced the increase in the prevalence of social frailty during the COVID-19 pandemic.

Social frailty is independently associated with geriatric depression among older adults living in northern Japan: A cross-sectional study of ORANGE registry.

AIM: To clarify prevalence of social frailty among older adults living in a rural Japanese community, and factors associated with social frailty status. METHODS: In total, 322 adults aged ≥65 years living in a Japanese rural community took part in the study from 2018 to 2020. Social frailty was defined as deficiencies of: (i) living alone; (ii) talking with someone every day; (iii) feeling helpful to friends or family; (iv) going out less frequently compared with last year; and (v) visiting friends sometimes. Social frail status was categorized as robust (0), social prefrail (1), and social frail (≥2), according to the summated score of Makizako's criteria. Multiple logistic regression analysis was applied to clarify factors associated with social frailty status. RESULTS: Final samples were classified into 68 persons with social frailty, 98 persons with social prefrailty and 147 persons as robust. We observed the prevalence of social frailty (21.7%) and social prefrailty (31.3%) and the GDS-15 had significantly high scores in the social frail groups. Social frailty was significantly associated with the GDS-15 score (odds ratio, 1.33; 95% CI, 1.19-1.49) and TMT-A (odds ratio, 1.04; 95% CI, 1.01-1.08) and GDS-15 (odds ratio, 1.13; 95% CI, 1.03-1.26) were extracted as independent variables of social prefrail status, with adjustment for demographics, polypharmacy and lifestyle-related diseases. CONCLUSIONS: Our results suggest that social frailty tends to be increasing gradually in a Japanese rural area, and social prefrailty might be potentially associated with attentional function, as well as the GDS-15 score. Geriatr Gerontol Int 2022; 22: 145-151.

[An examination for efficient project promotion of the initial-phase intensive support team for dementia in Akita Prefecture].

The purpose of this study was to clarify the trends in the activity of the initial-phase intensive support teams in Akita Prefecture and to, clarify the factors contributing to the more efficient promotion of future projects. A survey was conducted by questionnaire among 46 initial-phase intensive support team member for dementia. The results indicated that it is mostly maintained cooperation medical center for dementia and community support promoter for dementia. However, the question was insufficient cooperation with family doctor including visit the home. These findings suggest that it is important to disseminate information and improve awareness among the community as well as foster relationships of trust by families.

Preliminary report; Comparison of the circadian rest-activity rhythm of elderly Japanese community-dwellers according to sarcopenia status.

We investigated in a preliminarily study the circadian rest-activity rhythm of elderly Japanese community-dwellers according to sarcopenia status based upon the 2019 updated classification criteria of the Asian Working Group for Sarcopenia. A total of 30 participants were recruited from a single rehabilitation center in northern Japan between July and November 2019. The rest-activity rhythm of those with and without sarcopenia was assessed for 7 consecutive 24 h spans by wrist actigraphy in free-living condition and gait performance in the clinic. As group phenomena, the circadian activity rhythm of the sarcopenia cohort (N = 11) was of significantly lower amplitude and more fragmented than the non-sarcopenia cohort (N = 19). The nonparametric circadian rest activity (RAR) parameters of intra-daily variability (IV), relative amplitude (RA), most active 10-h span (M10), and the least active 5-h span (L5), but not interdaily stability (IS), of the sarcopenia group, were all significantly worse than those of the non-sarcopenia group. Gait performance for the sarcopenia group correlated strongly with the fragmentation and altered amplitude of the RAR. These preliminary findings motivated future longitudinal investigation both to improve the detection of sarcopenia in community dwelling elderly and to inform novel preventive or rehabilitative strategies.

The association between circadian rest-activity patterns and the behavioral and psychological symptoms depending on the cognitive status in Japanese nursing-home residents.

BACKGROUND: Limited information is available on the relationship between sleep disturbances during nighttime and the behavioral and psychological symptoms of dementia in older nursing-home residents. However, a few reports on the association between the circadian rest-activity rhythm and the behavioral and psychological symptoms of dementia in older residents have been published. The main objective of the present study was to examine the association among the circadian rest-activity rhythm, behavioral and psychological symptoms, and the cognitive function status among older individuals living in facilities. METHOD: The investigation was conducted from September 2017 to February 2018, and participants were recruited from five nursing homes in Akita prefecture, Japan, after obtaining patient agreement to participate in the study. To measure nonparametric circadian rest-activity parameters such as interdaily stability, intradaily variability, relative amplitude, mean of the least active 5-h period, and mean of the most active 10-h period, Actigraph devices were worn on the participants' nondominant wrists continuously for seven days. The score or classification of the cognitive status and the severity of the behavioral and psychological symptoms of dementia (BPSD) were assessed using the clinical dementia rating (CDR) and the dementia behavior disturbance scale (DBD), respectively. The binomial logistic regression model was applied to clarify which kinds of circadian rest-activity parameters predicted the cognitive status in nursing home residents as well as the BPSD outcome. A multi-level model was also used to examine the association between the nonparametric rest-activity parameters and the BPSD outcome explained by the cognitive status among older individuals in facilities. RESULTS: Seventy-seven participants (49 residents with dementia, and 28 residents without dementia) were included in this study. According to the binomial logistic regression analysis after adjusting for covariates, the classification of the cognitive status for older residents was associated with the DBD score (odds ratio, 1.22; 95% confidence interval [CI], 1.08, 1.38; p < 0.001), the IS (odds ratio, 0.01; 95% CI, 0.00, 1.00; p = 0.05) and the L5 (odds ratio, 0.99; 95% CI, 0.99, 1.00; p = 0.05). The results of a multi-level model also indicated that the IV at individual-level was significantly associated with the DBD score for nursing home residents, with the CDR score at cluster-level as an explanatory variable. As well, a significant association between the RA at individual level and the DBD score was observed in a multi-level model explained by the CDR score at cluster-level. CONCLUSION: Of these models, the multi-level model provided grounds for our proposal that the fragmentation or the amplitude of rest-activity parameters might be associated with the outcome of BPSD, considering the cognitive status of older individuals in different facilities. The findings offer practical insight into the prevention of BPSD and the improvement of rest-activity rhythms in rehabilitative care in nursing homes.

Sleep/awake status throughout the night and circadian motor activity patterns in older nursing-home residents with or without dementia, and older community-dwelling people without dementia.

BACKGROUND: Sleep disturbances are commonly observed in older nursing home residents, mainly in combination with dementia. However, sleep-associated circadian motor activity patterns have not been thoroughly investigated in Japanese nursing homes. The present study aimed to respectively clarify the effect of community living and the presence of dementia on sleep disturbances and interrupted activity rhythm of older nursing-home residents with or without dementia and older community-dwelling people without dementia. METHODS: Actigraph devices worn on the participants' non-dominant wrists for seven days were used to collect objective measurements of the sleep/awake status throughout the night and the circadian motor activity patterns. The presence of dementia was assessed by a trained medical doctor using the residents' records and the Clinical Dementia Rating (CDR). The functional capacity of the participants was determined using the Barthel Index (BI). RESULTS: Fifty-one older people in Akita prefecture were included in the current study, consisting of 17 residents with dementia (mean age: 82.2 years), 17 residents without dementia (84.5 years), and 17 community-dwelling people (83.6 years). The results showed that older nursing-home residents with dementia had significantly a lower rate of sleep efficiency and a longer awake time throughout the night than the other groups. Older nursing-home residents with and without dementia had more fragmented rhythm than community-dwelling people without dementia. CONCLUSION: These results provide evidence of poor sleep/awake status throughout the night and interrupted circadian activity rhythms in nursing-home residents with and without dementia. However, further studies performed according to dementia classifications are needed.

Deriving the reference value from the circadian motor active patterns in the "non-dementia" population, compared to the "dementia" population: What is the amount of physical activity conducive to the good circadian rhythm.

BACKGROUND: The circadian rhythm in older adults is commonly known to change with a decrease in physical activity. However, the association between circadian rhythm metrics and physical activity remains unclear. The objective of this study was to examine circadian activity patterns in older people with and without dementia and to determine the amount of physical activity conducive to a good circadian measurement. METHOD: Circadian parameters were collected from 117 older community-dwelling people (66 subjects without dementia and 52 subjects with dementia); the parameters were measured continuously using actigraphy for 7 days. A receiver operating characteristic (ROC) curve was applied to determine reference values for the circadian rhythm parameters, consisting of interdaily stability (IS), intradaily variability (IV), and relative amplitude (RA), in older subjects. RESULTS: The ROC curve revealed reference values of 0.55 for IS, 1.10 for IV, and 0.82 for RA. In addition, as a result of the ROC curve in the moderate-to-vigorous physical Activity (MVPA) conducive to the reference value of the Non-parametric Circadian Rhythm Analysis per day, the optimal reference values were 51 minutes for IV and 55 minutes for RA. However, the IS had no classification accuracy. CONCLUSIONS: Our results demonstrated the reference values derived from the circadian parameters of older Japanese population with or without dementia. Also, we determined the MVPA conducive to a good circadian rest-active pattern. This reference value for physical activity conducive to a good circadian rhythm might be useful for developing a new index for health promotion in the older community-dwelling population.