Association between dynapenia and cognitive decline in community-dwelling older Japanese adults: The IRIDE Cohort Study.

AIM: Muscle mass and strength correlate with cognitive function; however, it remains unclear whether dynapenia (i.e., muscle weakness with preserved muscle mass) is relevant. This study aimed to explore whether dynapenia is associated with global cognitive function in community-dwelling older Japanese adults. METHODS: This cross-sectional study used data from the Integrated Research Initiative for Living Well with Dementia Cohort Study, which pooled data from five community-based geriatric cohorts. Dynapenia was defined as muscle weakness without muscle mass loss according to the Asian Working Group for Sarcopenia criteria. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). An ordered logistic regression analysis was conducted with dynapenia as the exposure and with cognitive decline stages, defined as an MMSE score of 27-30 for normal cognition, 24-26 for possible cognitive decline, and <24 for cognitive decline, as the outcome, stratified by sex and adjusted for age, muscle mass, education, alcohol consumption, smoking habits, living alone, and non-communicable diseases. RESULTS: We analyzed data for 3338 participants (2162 female) with preserved muscle mass. Of these, 449 (13.5%) had dynapenia, and 79 (2.4%) exhibited cognitive decline. Multivariate odds ratios (95% confidence interval) for cognitive decline among those with dynapenia, compared with those without dynapenia, were 1.51 (1.02-2.24) for males and 2.08 (1.51-2.86) for females. CONCLUSIONS: Muscle weakness is associated with cognitive decline, even in individuals with preserved muscle mass. Further studies are needed to better understand the association between muscle weakness and cognitive decline over time in order to develop dementia prevention strategies for those with dynapenia. Geriatr Gerontol Int 2024; 24: 123-129.

Fluctuations in Cognitive Test Scores and Loss to Follow-Up in Community-Dwelling Older Adults: The IRIDE Cohort Study.

INTRODUCTION: We examined the relationship between previous fluctuations in Mini-Mental State Examination (MMSE) scores, future changes in MMSE scores, and attrition from follow-up surveys, which helps in a more comprehensive interpretation of repeatedly collected MMSE scores. METHODS: This 4-year longitudinal study included 2,073 community-dwelling older adults aged ≥65 years in Japan. The MMSE was administered at baseline (T0), 2 years (T1), and 4 years (T2) follow-up. We performed multinomial logistic regression analysis with the dependent variable, indicating the change in MMSE score from T1 to T2 (categorized as increase, no change [reference category], and decrease) and attrition at T2. The independent variables included the change in MMSE scores from T0 to T1 and MMSE scores at T0 and T1. RESULTS: The mean MMSE score was 29 across the three time points. A one-point decrease in MMSE score from T0 to T1 was associated with 79% (95% confidence interval: 1.62, 1.97) higher odds of an increase in MMSE score from T1 to T2 and 28% (1.17, 1.40) higher odds of attrition at T2. A one-point decrement in the MMSE score at T0 and T1 was also associated with an increase in the MMSE score from T1 to T2 and attrition at T2. CONCLUSION: Focusing on cognitive fluctuation for 2 years, rather than cognitive function at a point in time, would have no remarkable advantage when focusing on future cognitive function and attrition. Our results emphasize the need for further studies to identify factors that distinguish between those who continue to attend follow-up surveys and show improvements in cognitive test scores and those who drop out.

Age- and sex-specific associations between sarcopenia severity and poor cognitive function among community-dwelling older adults in Japan: The IRIDE Cohort Study.

Introduction: This study examined whether the association between sarcopenia severity and cognitive function differed according to sex and age in community-dwelling older adults in Japan. Methods: This is a cross-sectional study of older adults (age ≥ 65 years) consisting of five regional cohorts integrated as the Integrated Research Initiative for Living Well with Dementia (IRIDE) Cohort Study. Sarcopenia severity was determined based on the Asian Working Group for Sarcopenia 2019, which assessed grip strength, walking speed, and skeletal muscle mass index. Poor cognitive function was defined as a Mini-Mental State Examination score of ≤ 23. Odds ratios (ORs) and 95% confidence intervals (CIs) for poor cognitive function were calculated by sex and age group (65-74 and ≥75 years) using binomial logistic regression models, which were adjusted for age, educational attainment, history of non-communicable diseases, smoking and drinking habits, living alone, frequency of going outdoors, exercise habits, and depressive symptom. Results: Of the 8,180 participants, 6,426 (1,157 men aged 65-74 and 1,063 men aged 75 or older; 2,281 women aged 65-74 and 1,925 women aged 75 or older) were analyzed. The prevalence ratio of sarcopenia and severe sarcopenia were 309 (13.9%) and 92 (4.1%) among men and 559 (13.3%) and 166 (3.7%) among women, respectively. A total of 127 (5.8%) men and 161 (3.9%) women had a poor cognitive function. Setting non-sarcopenia as a reference, the adjusted ORs (95% CI) of poor cognitive function were 2.20 (1.54, 3.15) for sarcopenia and 3.56 (2.20, 5.71) for severe sarcopenia. A similar trend was observed in analyses stratified by sex and age, with linear associations (P for trend <0.05) in both categories. Furthermore, there was a significant interaction (P < 0.05) between sex and sarcopenia severity, indicating a stronger linear association of sarcopenia severity with poor cognitive function in women compared with men. Discussion and conclusion: Sarcopenia severity was linearly associated with poor cognitive function in adults aged ≥ 65 years, with a stronger association in women compared with men.

Early strong predictors of decline in instrumental activities of daily living in community-dwelling older Japanese people.

OBJECTIVE: Our aim is to determine the strong predictors of the onset of instrumental activities of daily living (IADL) decline in community-dwelling older people. DESIGN: A prospective cohort study with a two-year follow-up. SETTING: Kashiwa City, Chiba Prefecture, Japan and Toshima Ward, Tokyo Metropolitan, Japan. PARTICIPANTS: The data were acquired from two cohorts. The final sample comprised 1,523 community-dwelling older people aged 65-94 years (681 men, 842 women). They were individuals who were independent in IADL at baseline and participated in follow-up IADL assessments two years later. MEASUREMENTS: At baseline, comprehensive assessments were performed including: health interview, gait function, hand-grip strength, skeletal muscle mass, balance function, oral function, dietary lifestyle, cognitive function, quality of life, mental status, and social network. When the two-year follow-up was performed, IADL declines were observed in 53 out of 1,523 people. The association of each Z-transformed parameter with the occurrence of IADL decline was examined by employing a binominal logistic regression model adjusting for age, gender, body weight, body height, and medical history. An odds ratio (OR) and a 95% confidence interval were calculated and compared between different parameters. RESULTS: A decrease in walking speed and one-legged stance time, whereas an increased timed up & go test time was associated with significant ORs for the occurrence of IADL decline. CONCLUSION: Gait-related parameters appear to be the strong predictors of the onset of IADL decline in community-dwelling older people.

Simple screening models for cognitive impairment in community settings: The IRIDE Cohort Study.

AIM: Community settings often need simple screening, rather than detailed tests, to identify cognitive impairment. This study aimed to develop models to screen older adults with cognitive impairment. METHODS: This study used data from the Integrated Research Initiative for Living Well with Dementia Cohort Study and included 5830 older adults. Individuals were considered cognitively impaired if their Mini-Mental State Examination score was less than 24. Three screening models were developed: the simple model (age, sex, and education), the base model comprising 13 candidate variables available in the questionnaire, and the enhanced model, where grip strength and gait speed were added to the base model. We performed binary logistic regression analysis with stepwise backward elimination (P < 0.1 for retention in the model) to develop each model. Then, we calculated integer scores from coefficients to develop score-based models. The area under the receiver operating characteristic curve (AUC) was used to evaluate discrimination. RESULTS: Participants with cognitive impairment accounted for 4.0% (n = 233) of the total. The score-based simple model comprised three variables (AUC = 0.72, sensitivity: 72%, specificity: 61%). The score-based base model included nine variables (AUC = 0.76, sensitivity: 70%, specificity: 67%). The score-based enhanced model comprised eight variables, including grip strength and gait speed (AUC = 0.79, sensitivity: 73%, specificity: 70%). CONCLUSIONS: This study developed three screening models with acceptable discriminant validity for cognitive impairment. These models comprised simple questionnaire-based items and common physical performance measurements. These models could enable screening of older adults suspected of cognitive impairment without the need to conduct cognitive tests in community settings. Geriatr Gerontol Int 2022; 22: 292-297.

Walking is regulated by environmental temperature.

The mechanisms that regulate human walking are not fully understood, although there has been substantial research. In our study, we hypothesized that, although walking can be volitionally modified, it is also involuntary and controlled by evolutionary factors, such as the relationship between temperature and movement speed in poikilotherms. This study aimed to determine the effects of environmental temperature on speed, step length, and cadence during unrestrained walking over long periods. Customers of a private insurance company were asked to use a background smartphone GPS application that measured walking parameters. Participants were 1065 app users (298 men and 767 women) aged 14-86 years. Observed walking speed and cadence were higher in winter (average maximum temperature: 10.2 °C) than in summer (average maximum temperature: 29.8 °C) (p < 0.001). The walking parameters were closely related to environmental temperature, with cadence most strongly correlated with daily maximum temperature (r = - 0.812, p < 0.001) and indicating a curvilinear relationship. A decrease in environmental temperature was found to increase cadence when the temperature was below 30 °C. The findings suggest that walking may be regulated by environmental temperature and potentially by the autonomic nervous system's response to environmental temperature.

Change in outdoor walking behavior during the coronavirus disease pandemic in Japan: A longitudinal study.

BACKGROUND: Due to the high infectivity and seriousness of coronavirus disease, people's daily activities were restricted in countries worldwide; governments implemented lockdown measures and advised individuals to perform self-restraint in terms of leaving the house. However, there have been few scientific reports on the effects of such behavioral restrictions on walking parameters. RESEARCH QUESTION: Did behavioral restrictions during the state of emergency in Japan effect walking parameters in daily life outdoor walking? METHODS: In this retrospective cohort study, four walking parameters, namely, the average number of steps taken, walking speed, step length, and cadence, were measured using a smartphone application among 3901 participants (mean age ± standard deviation: 60.3 ± 28.9 years) from March 2 to June 15 in both 2019 and 2020. Repeated-measures two-way analysis of variance was used to compare the walking parameters between the two years. RESULTS: The number of steps significantly decreased (p < .001) in 2020 (∼3400 steps) compared to that in 2019 (∼4400 steps), indicating that the state of emergency greatly affected the amount of physical activity performed per individual. Conversely, walking speed increased (p < .001 during the period when the state of emergency was issued) in 2020 (∼1.25 m/s) compared to that in 2019 (∼1.23 m/s), attributable to an increased step length. SIGNIFICANCE: Although changes in walking speed and step length were small compared to those in the number of steps, those changes were consistently seen during the state of emergency, suggesting that people tried to walk faster in their outdoor walking. Such change in walking behavior may have protected further deterioration of health due to restricted activity.

Comparison of Two Evacuation Shelter Operating Policies and the Role of Public Health Nurses after the Great East Japan Earthquake: A Qualitative Study.

This study describes shelter operations by public health nurses (PHNs) in Kesennuma City, located near the epicenter of the Great East Japan Earthquake, which occurred on March 11, 2011. The data were semi-structured interviews with 10 PHNs, 2 nutritionists, and 2 general administrators conducted from July 2013 to January 2014. All transcripts were analyzed using the constructivist grounded theory approach. We identified two operating methods for shelters: shelters stationed by PHNs in the Old City, and shelters patrolled by PHNs in the merged district. These methods were compared using four themes. In emergency situations, "operational periods," a predetermined short term for a leader to perform his/her duties responsibly, could be adopted for relatively small organizations on the frontline. PHNs must not only attempt to operate shelters on their own but also encourage residents to manage the shelters as well. Moreover, human resource allocation should be managed independently of personal factors, as strong relationships between shelter residents would sometimes disturb the flexibility of the response. Even when a situation requires PHNs to stay in shelters, frequent collecting of information and updating the plan according to response progress will help to maintain effective shelter operations.

Reference value on daily living walking parameters among Japanese adults.

AIM: Walking speed is closely related to numerous health outcomes. It has typically been measured in laboratory settings, where individuals can intentionally change their walking speed. It can be accurately measured in daily life using a smartphone global positioning system. We aimed to present a reference value on walking speed in daily life by sex and age. METHODS: The data were obtained using a walking monitoring service involving global positioning system technology. A secondary data analysis was carried out. Four daily living walking parameters - daily living walking speed, daily living walking cycle, daily living step length and daily living cadence - of 8429 Japanese persons were measured in their daily life using a smartphone application. RESULTS: The means (standard deviations) of daily living walking speed, daily living walking cycle, daily living step length and daily living cadence were 1.30 m/s (0.10 m/s), 1.02 s (0.06 s), 65.55 cm (5.38 cm) and 118.86 steps/min (6.76 steps/min), respectively. Notably, daily living walking speed in those aged >65 years was significantly slower than in those aged <65 years. CONCLUSIONS: The present reference values and age differences of daily living walking parameters can be used to compare daily living walking speed data measured by other devices, such as accelerometers. This could allow for a consensus on the definition of daily walking speed that can be utilized for assessing health outcomes among older individuals. Geriatr Gerontol Int 2020; 20: 664-669.

Test-retest reliability of daily life gait speed as measured by smartphone global positioning system.

BACKGROUND: Gait speed is useful in predicting adverse health outcomes among older adults. In previous studies, gait speed has typically been measured when subjects walk in laboratory settings, where they are able to intentionally change their gait speed. Thus, it is unclear whether the gait speed captured in a laboratory setting is representative of the subjects' actual walking pace in daily life. RESEARCH QUESTION: This study proposes using the more accurate "daily life gait speed" (DGS), measured as the subject's average gait speed over a week-long period using the global positioning system (GPS) in their smartphone. We examined the test-retest reliability of the DGS measure in the present study. METHODS: Three daily life gait parameters with 186 volunteers (57 men and 129 women), aged 19 to 84 years, were measured using a smartphone application: DGS, average of daily gait cycle during a week (DCY), and average of daily cadence during a week (DCA). Test-retest reliability of the daily gait parameters between test week (T1) and retest week (T2) was assessed with the intraclass correlation coefficient, ICC (2,1), and systematic biases were observed via Bland-Altman plots. RESULTS: The ICCs between the daily gait parameters at T1 and T2 were 0.902 for DGS, 0.916 for DCY, and 0.917 for DCA. The Bland-Altman plots showed no significant fixed or proportional bias between the measurements at T1 and T2. SIGNIFICANCE: These results verify that the test-retest reliability of the daily gait parameters in the present study was adequate.

Evacuation Decision Making and Expanded Roles of Adult Daycare Services in the Great East Japan Earthquake: Qualitative Analysis Using Semistructured Interviews.

CONTEXT: The roles of adult daycare services during disaster evacuations in the relationships with community resilience are unknown. The initial 72 hours after a disaster are crucial because people in the disaster area depend on their own efforts or the resources available at the moment until the arrival of external support. OBJECTIVE: To clarify the evacuation-related decision making of the administrators of adult daycare services within 72 hours after the Great East Japan Earthquake and to describe the roles of adult daycare services during the month following the earthquake. DESIGN: Qualitative study using semistructured interviews. The transcribed interviews were analyzed anonymously through an inductive qualitative content analysis using ATLAS.ti. SETTING: Kesennuma City, Miyagi Prefecture. PARTICIPANTS: Eleven key informants (3 primary care providers and 8 administrators) from 8 institutions. RESULTS: Immediately after the disaster, 6 institutions implemented shelter-in-place. The evacuation behaviors of the adult daycare institutions were diverse, but each institution was transformed repeatedly within 72 hours. With respect to evacuation decision making, the primary issues involved whether to go to mandatory evacuation sites. However, after 3 days, the institutions relocated from these sites to other places. During a period of approximately 1 month, 7 institutions managed the evacuation of service users and care providers. The expanded institutional roles were as follows: "confirming the safety of the users' families," "substituting residential facilities," and "imposing leadership during the evacuation." CONCLUSIONS: If institutions choose to shelter-in-place, it should be sustained for as long as possible. Sufficiently planned stores of food and water to accommodate daytime users are needed. Institutions that employ shelter-in-place as an evacuation plan should maintain close contact with local governments. Furthermore, local governments should predetermine how to manage these institutions in the event of a disaster. To build community resilience for disasters, developing linkage with private organizations' resilience is beneficial.

Femoral muscle mass relates to physical frailty components in community-dwelling older people.

AIM: To examine the relationship between lower limb muscle (femoral muscle, calf muscle) mass and exercise capacity, and frailty components in community-dwelling older people. METHODS: Participants included 121 community-dwelling individuals. There were 42 men and 79 women, and the mean age was 77.7 years (range 56-97 years). Appendicular skeletal muscle mass was determined using dual-energy X-ray absorptiometry, and the skeletal muscle index was calculated using the following formula: appendicular skeletal muscle / body height2 . Femoral muscle mass and calf muscle mass were determined, respectively, by dividing the femoral bone and tibial bone at the knee joint space. A symptom-limited cardiopulmonary exercise testing was carried out and peak oxygen uptake was measured. Functional exercise performance was evaluated using the handgrip strength measurement, comfortable walking speed, and the Timed Up and Go test. All patients gave written, informed consent before data collection. RESULTS: Peak oxygen uptake correlated positively with the skeletal muscle index (r = 0.491). Only femoral muscle mass that was corrected with the whole body muscle mass was positively correlated with peak oxygen uptake (r = 0.473), handgrip strength (r = 0.382), comfortable walking speed (r = 0.427), and the Timed Up and Go test (r = 0.379). Calf muscle mass that was corrected with the whole-body muscle mass showed no correlation with exercise capacity and frailty components. A similar tendency was observed in both men and women. CONCLUSIONS: Femoral muscle mass influenced exercise capacity and physical frail components compared with calf muscle mass. These results suggest the importance of the femoral muscle in physical frailty. Geriatr Gerontol Int 2017; 17: 1636-1641.

Eating Alone as Social Disengagement is Strongly Associated With Depressive Symptoms in Japanese Community-Dwelling Older Adults.

OBJECTIVES: Depression in later life poses a grave challenge for the aging countries. The reported key risk factors include social disengagement, but the lack of social companionship during mealtimes, namely eating alone, has not been examined extensively, especially in relation to living arrangement. Past studies on changes along geriatric trajectories in the association between social engagement and depression also remain inadequate. This study aims to examine the association between social engagement and depressive symptoms with a particular focus on eating alone and how the association changes along the aging and mental frailty trajectories. DESIGN: A cross-sectional study. SETTING: Kashiwa-city, Chiba-prefecture in Japan. PARTICIPANTS: A total of 1856 community-dwelling older adults. MEASUREMENTS: The 15-item Geriatric Depression Scale was used to measure depressive symptoms. The indicators used to assess social engagement included eating alone, living arrangement, reciprocity of social support, social participation, social stressors and social ties. RESULTS: Social engagement was significantly associated with depressive symptoms. Those who live with their families yet eat alone were found to be at particular risk (odds ratio = 5.02, 95% confidence interval 2.5-9.9 for young-old; odds ratio = 2.41, 95% confidence interval 1.2-4.8 for old-old). Younger and less mentally frail populations showed stronger associations. CONCLUSIONS: Eating alone was a key risk factor for depressive symptoms in community-dwelling older adults. The living arrangement in which they eat alone is important in identifying those with the greatest risk. Mental health management for older adults requires comprehensive assessment of their social relations that takes into account their companionship during mealtimes. Social preventive measures need to involve early interventions in order to augment their effectiveness against mental frailty.

Development of a simple screening test for sarcopenia in older adults.

AIM: To develop a simple screening test to identify older adults at high risk for sarcopenia. METHODS: We studied 1971 functionally independent, community-dwelling adults aged 65 years or older randomly selected from the resident register of Kashiwa city, Chiba, Japan. Data collection was carried out between September and November 2012. Sarcopenia was defined based on low muscle mass measured by bioimpedance analysis and either low muscle strength characterized by handgrip or low physical performance characterized by slow gait speed. RESULTS: The prevalence of sarcopenia was 14.2% in men and 22.1% in women. After the variable selection procedure, the final model to estimate the probability of sarcopenia included three variables: age, grip strength and calf circumference. The area under the receiver operating characteristic curve, a measure of discrimination, of the final model was 0.939 with 95% confidence interval (CI) of 0.918-0.958 for men, and 0.909 with 95% CI of 0.887-0.931 for women. We created a score chart for each sex based on the final model. When the sum of sensitivity and specificity was maximized, sensitivity, specificity, and positive and negative predictive values for sarcopenia were 84.9%, 88.2%, 54.4%, and 97.2% for men, 75.5%, 92.0%, 72.8%, and 93.0% for women, respectively. CONCLUSIONS: The presence of sarcopenia could be detected using three easily obtainable variables with high accuracy. The screening test we developed could help identify functionally independent older adults with sarcopenia who are good candidates for intervention.