Estimating the Effect of Engagement in Community-Based Going-Out Program on Incidence Disability in Older Adults.

OBJECTIVES: Although going out has been reported to be associated with the incidence of disability, few studies have investigated the effect of community-based programs to promote going out on the incidence of disability. This study aimed to estimate the effects of a program fostering going-out on the incidence of disability in community-dwelling older adults. DESIGN: Longitudinal, observational study. SETTING AND PARTICIPANTS: Nonengaged (n = 1086) and engaged older adults (n = 1086) enrolled in the National Center for Geriatrics and Gerontology Study of Geriatric Syndrome by using a one-to-one nearest neighbor propensity score-matching scheme. METHODS: After the baseline assessments, participants in the community-based going-out program received a specialized physical activity tracker, monitored their daily physical activity, and received personalized feedback on going out to community facilities with a system for reading the device for 12 months. Disability onset was defined as a new case of long-term care under the public insurance certification in Japan within 48 months of program completion. The absolute risk reduction and the number needed to treat for the incidence of disability were calculated for the nonengaged and engaged groups. Cox proportional hazard regression analysis, using inverse probability weighting was used to obtain the hazard ratio. RESULTS: Disabilities occurred in 112 individuals in the matched nonengaged group and 51 individuals in the engaged group. The absolute risk reduction was 5.67% (95% CI 3.46%-7.88%). The number needed to treat was 18 (95% CI 13-29). The hazard ratio, with the nonengaged group as the reference, was 0.49 (95% CI 0.36-0.67). CONCLUSIONS AND IMPLICATIONS: This longitudinal observational study suggested that a community-based program could prevent 1 disability in every 18 participants. This program does not require a professional instructor, only the distribution of devices and system installation, and it could be beneficial as a population-based approach to preventing disabilities.

Association between COVID-19 emergency declarations and physical activity among community-dwelling older adults enrolled in a physical activity measurement program: Evidence from a retrospective observational study using the regression discontinuity design.

BACKGROUND: The current study examines the negative impact of the coronavirus disease 2019 (COVID-19) emergency declarations on physical activity among the community-dwelling older adults, the participants of a physical activity measurement program, in Japan. METHODS: This retrospective observational study included 1,773 community-dwelling older adults (aged 74.6 ± 6.3 years, 53.9% women) who had participated in the physical activity measurement project from February 2020 to July 2021. We measured physical activity using a tri-axial accelerometer during 547 consecutive days. Three emergency declarations, requesting people to avoid going outside, occurred during the observational period. We multiply-imputed missing values for daily physical activity, such as steps, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) for several patterns of datasets according to the maximum missing rates on a person level. We mainly report the results based on less than 50% of the maximum missing rate (n = 1,056). Other results are reported in the supplemental file. Changes in physical activity before and after the start of each emergency declaration were examined by the regression discontinuity design (RDD) within 14-, 28-, and 56-day bandwidths. RESULTS: For all the participants in the multiply-imputed data with the 14-day bandwidth, steps (coefficients [[Formula: see text]][Formula: see text] 964.3 steps), LPA ([Formula: see text] 5.5 min), and MVPA ([Formula: see text] 4.9 min) increased after the first emergency declaration. However, the effects were attenuated as the RDD bandwidths were widened. No consistent negative impact was observed after the second and third declarations. After the second declaration, steps ([Formula: see text]-609.7 steps), LPA ([Formula: see text]-4.6 min), and MVPA ([Formula: see text]-2.8 min) decreased with the 14-day bandwidth. On the other hand, steps ([Formula: see text] 143.8 steps) and MVPA ([Formula: see text] 1.3 min) increased with the 56-day bandwidth. For the third declaration, LPA consistently decreased with all the bandwidths ([Formula: see text]-2.1, -3.0, -0.8 min for the 14, 28, 56-day bandwidth), whereas steps ([Formula: see text]-529 steps) and MVPA ([Formula: see text]-2.6 min) decreased only with the 28-day bandwidth. CONCLUSIONS: For the community-dwelling older adults who regularly self-monitor their physical activity, the current study concludes that there is no evidence of consistently negative impacts of the emergency declarations by the COVID-19 pandemic.

Association between daily gait speed patterns and cognitive impairment in community-dwelling older adults.

Gait speed over a short distance is associated with cognitive impairment in older adults. Recently, daily gait speed has been assessed using accelerometers. However, because daily gait speed is only weakly correlation with gait speed over a short distance, its association with cognitive impairment needs to be investigated. The present study compared the daily gait speed patterns of normal cognition (NC), mild cognitive impairment (MCI), and general cognitive impairment (GCI) subjects measured every 3 h for two weeks using accelerometers. A total of 1959 participants were classified into the NC (N = 1519), MCI (N = 353), and GCI groups (N = 87). The results showed that the average daily gait speed of the GCI group was significantly lower than that of the NC group (p = 0.03). Furthermore, the average daily gait speeds of the MCI and NC groups were the same. However, the average daily gait speed of the MCI group during a specific time (12-15 o'clock) was significantly lower than that of the NC group (p < 0.01). These results suggest that changes in daily patterns may be detected by measuring daily gait speed, which depends on the degree of cognitive function.

Light intensity physical activity is beneficially associated with brain volume in older adults with high cardiovascular risk.

Background: Older people with high cardiovascular risk, including those without cardiovascular diseases, are an at-risk population for dementia. Regular physical activity is generally recommended to maintain brain health; however, the optimal intensity of physical activity for maintaining brain volume in older adults with cardiovascular risk remains unclear. We examined the associations between intensity-specific physical activity and brain volume stratified by absolute cardiovascular risk level in older adults without cardiovascular diseases. Methods and results: This cross-sectional study involved 725 community-dwelling older Japanese adults without cardiovascular diseases. We estimated absolute cardiovascular risk using the World Health Organization risk estimation charts, which include variables such as age, sex, diabetes mellitus, smoking, systolic blood pressure, and total cholesterol, and stratified cardiovascular risk level into three risk categories: low (≤ 9%), moderate (10-14%), and high (≥15%). We measured daily physical activity using a triaxial accelerometer, and calculated the average time spent in moderate-to-vigorous intensity physical activity (MVPA) and light intensity physical activity (LPA). We performed brain T1-weighted magnetic resonance imaging and calculated the volume of the cortical gray matter, subcortical gray matter, and cerebral white matter, using the FreeSurfer software. In the overall sample, multivariable linear regression analysis showed that greater MVPA was significantly associated with greater volume of the cortical gray matter and cerebral white matter, and greater LPA was significantly associated with greater volume of the cerebral white matter. Additionally, in the analysis of the sample stratified by absolute cardiovascular risk level, cerebral white matter volume was significantly associated with both MVPA and LPA in the high cardiovascular risk group. Conclusions: The association between physical activity and brain volume differed according to cardiovascular risk level in community-dwelling older adults. In a population at high cardiovascular risk, maintaining or increasing LPA might be a practical and achievable strategy for healthy brain aging.

Predictivity of daily gait speed using tri-axial accelerometers for two-year incident disability among Japanese older adults.

Gait speed is an important indicator of functional decline in older adults. Recently, daily gait speed has been assessed using accelerometers. However, it is unclear whether this parameter can predict the decline in functional abilities. This study investigates whether daily gait speed can be a predictor of incident disability risk as well as in-laboratory gait speed. A sample of 1860 older adults (Male: 728, Female: 1132; 70.1 ± 6.2 years) were instructed to wear accelerometers on the waist. The association between daily gait speed for two weeks and incident disability during a two-year period was analyzed by using the cut-off value for screening prefrailty in the previous study (106.3 cm/s). Furthermore, the associations with in-laboratory gait speed (cut-off value: 100 cm/s), number of steps (cut-off value: 6342.2 steps/day), and incident disability were also analyzed. Cox proportional hazards analysis showed a significant hazard ratio of low daily gait speed (HR, 2.97; p = 0.02) comparable to that of low in-laboratory gait speed (HR: 2.53; p = 0.01). Conversely, the number of steps had no significant association with incident disability (HR: 1.99; p = 0.12). These results suggest that daily gait speed can be a predictor of incident disability risk in older adults.

Isotemporal Substitution of Sedentary Behavior With Moderate to Vigorous Physical Activity Is Associated With Lower Risk of Disability: A Prospective Longitudinal Cohort Study.

OBJECTIVE: The purpose of the study was to estimate, using an isotemporal substitution model, the effect of replacing sedentary behavior (SB) with physical activity on the incidence of disability in community-dwelling older adults. METHODS: This 2-year longitudinal cohort study enrolled 3691 community-dwelling older adults (57.2% women; mean age = 74.0 [SD = 5.0] years). Individuals with dementia, stroke, Parkinson disease, depression, low Mini-Mental State Examination scores, dependence on basic activities of daily living, and missing data were excluded. Physical activity and potential confounding factors were investigated as a baseline survey of disability incidence, defined by Japanese long-term care insurance certification, for 2 years in 2 regions. Physical activity data (SB, light-intensity physical activity, and moderate- to vigorous-intensity physical activity [MVPA]) were measured using triaxial accelerometers for 14 days, and daily mean time spent in each physical activity parameter was computed in increments of 10 minutes. The relationship between baseline physical activity and disability incidence adjusted for potential confounders was analyzed using multilevel Cox proportional hazards regression analyses with an isotemporal substitution model. RESULTS: The disability incidence rate was 3.8%, excluding individuals who could not be followed-up. Replacing 10 minutes of SB per day with MVPA was associated with a decreased disability incidence (hazard ratio = 0.870; 95% CI = 0.766-0.988), whereas no evidence was found for replacing SB with light-intensity physical activity (hazard ratio = 0.980; 95% CI = 0.873-1.10). CONCLUSIONS: Replacing SB with MVPA was associated with a lower risk of disability. These findings are helpful for establishing disability prevention strategies. IMPACT: These results suggest that feasible changes in daily behavior, such as replacing 10 minutes of SB with MVPA daily, might have a protective effect on disability incidence. Clarifying these associations is useful for developing disability prevention strategies and may help reduce the incidence of disability in community-dwelling older adults.

Difference in sarcopenia characteristics associated with physical activity and disability incidences in older adults.

BACKGROUND: Deteriorated skeletal muscle condition, including sarcopenia, is a risk factor for disability in older adults. Promoting physical activity is a useful treatment for sarcopenia. However, optimal intensity of physical activity according to sarcopenia characteristics is unclear. METHODS: This longitudinal cohort study enrolled 2149 community-dwelling older adults (women 55.7%, mean age: 75.5 ± 4.0 years). Five-year disability incidence defined by Japanese long-term care insurance certification and accelerometer-measured physical activities (light-intensity physical activity [LPA] and moderate-to-vigorous intensity physical activity [MVPA]), which were adjusted for potential confounders, was analysed using cox-proportional hazard model stratified by sarcopenia characteristics based on the diagnostic algorithm by the Asian working group for sarcopenia (robust, low physical function, low muscle mass, and sarcopenia). The sarcopenia group was defined as low muscle mass and low physical function (weakness and/or slowness). The low muscle mass and low physical function groups were each defined by these characteristics alone. Muscle mass was analysed via bioelectrical impedance analysis. Each intensity of physical activity times was divided by median values. RESULTS: The disability incidence rate was 15.4%, excluding those who could not be followed up. Mean LPA times were 43.8 ± 18.0, 45.6 ± 17.5, 45.4 ± 16.6, 40.8 ± 18.6, and 41.4 ± 18.5 min/day and MVPA times were 24.6 ± 17.6, 26.3 ± 18.3, 27.2 ± 17.3, 21.6 ± 16.3, and 21.5 ± 16.4 min/day in all participants, the robust, low muscle mass, low physical function, and sarcopenia groups, respectively. For all participants, higher MVPA was associated with disability incidence [hazard ratios (HR), 0.63; 95% confidence interval (95% CI), 0.49-0.81; P < 0.001], whereas higher LPA showed no association (HR, 0.86; 95% CI, 0.68-1.10; P = 0.22). Higher LPA was associated in the sarcopenia group (HR, 0.35; 95% CI, 0.15-0.85; P = 0.019), and MVPA was associated in the robust (HR, 0.58; 95% CI, 0.39-0.87; P = 0.008) and low physical function (HR, 0.66; 95% CI, 0.45-0.98; P = 0.040) groups. Both LPA and MVPA showed no association in the low muscle mass group. The P values for interactions between sarcopenia characteristics and physical activity were 0.017 for LPA and 0.014 for MVPA. CONCLUSIONS: The LPA was associated with a lower risk of disability in older adults with sarcopenia, whereas MVPA was associated in subjects with robust and low physical function. Our findings indicate a need for individualized approaches to prevent disability based on muscle condition.

Screening prefrailty in Japanese community-dwelling older adults with daily gait speed and number of steps via tri-axial accelerometers.

Prefrailty is an intermediate stage between non-frailty and frailty. It is associated with an increased risk of progression to frailty, which makes it important to screen older adults for prefrailty at an early stage. This study verified whether daily gait speed and number of steps measured using a tri-axial accelerometer could be used to identify prefrailty. In total, 1692 Japanese community-dwelling older adults were divided into robust (n = 1032) and prefrail (n = 660) groups based on the Kihon Checklist, which is a self-administered questionnaire. Both daily gait speed and number of steps were measured for two weeks using tri-axial accelerometers. We also calculated the area under the ROC curve and the cut-off values for these parameters. Our results showed that the cut-off value for daily gait speed was 106.3 cm/s, while that for number of steps was 6342.2. In addition, we found that the combined assessment of both cut-off values was a more effective way to screen older adults with prefrailty status compared to either parameter alone. This is also considered an effective way to reduce national expenditures for daily care assistance.

Relationship between Daily and In-laboratory Gait Speed among Healthy Community-dwelling Older Adults.

Gait speed in laboratory settings (in-laboratory gait speed) is one of the important indicators associated with the decline in functional abilities in older adulthood. Recently, it has become possible to measure gait speed during daily living (daily gait speed) using accelerometers. However, the relationship between these two gait speed parameters is unclear. This study aimed to compare in-laboratory gait speed, measured by a sheet-type pressure sensor, and daily gait speed, measured by an accelerometer, in healthy community-dwelling older adults. Participants were aged ≥60 years, residing in Takahama city, Aichi, Japan. To calculate daily gait speed, participants were instructed to wear a tri-axial accelerometer on their waist. A total of 1965 participants were included in the final analysis. The results showed a weak association (r = 0.333, p < 0.001) between the two gait speed parameters. Furthermore, average daily gait speed was significantly lower than average in-laboratory gait speed. However, both gait speed parameters declined significantly with age. These results suggest that, in addition to in-laboratory gait speed, daily gait speed may be a helpful parameter for predicting decline in functional abilities.

Effects of promoting daily physical activity on physical and mental health in older individuals.

[Purpose] A trial was conducted to examine the effects of promoting daily physical activity, tailored to specific living situations, on physical and mental health indicators in older adults. [Participants and Methods] Participants in the 'Intervention' group (N=21) wore accelerometers during the 12-week trial period, and for one week during preliminary and follow-up surveys. Based on their physical activity levels as measured by accelerometers, participants were given instructions to increase their daily physical activity. Participants in the 'Control' group (N=18) wore the accelerometer only during the preliminary and follow-up survey. [Results] Number of steps increased significantly in the intervention group and a significant decrease in light physical activity time was observed in the control group. No such decrease was observed in the intervention group. With regard to health-related quality of life, significant interactions were observed between groups based on the 36-Item Short-Form Health Survey Mental Component Summary score, and some sub-items. A combined analysis of both groups found a significant positive correlation between the change in light physical activity time and the Mental Component Summary score. [Conclusion] An increase in daily physical activity was considered to have a sustained bolstering effect on mental health.

Foot pressure analysis of gait pattern in older Japanese females requiring different personal care support levels.

[Purpose] This study evaluated gait parameters and foot pressure in two regions of the feet among older females with different personal care support needs to analyze factors that contribute to higher support requirements. [Subjects and Methods] Thirty-two older females were divided into support-need and care-need level groups. Gait parameters (speed, cadence, step length, step width, gait angle, toe angle, double support phase, swing phase, and stance phase) and foot pressure during a 5-m walk were measured and analyzed in the two groups. [Results] The percentage of the double support phase on both feet and the right stance phase were significantly higher in the care-need level group, while that of the right swing phase was significantly lower than that of the support-need level group. Additionally, the phase showing peak pressure on the left rear foot was significantly delayed and the left forefoot pressure in the terminal stance was significantly lower in the care-need level group than in the support-need level group. [Conclusion] These findings show that the temporal duration parameters and foot pressure on a particular side were significantly different between the two groups and suggest that these differences were associated with a higher care level.

Elongation of amyloid fibrils through lateral binding of monomers revealed by total internal reflection fluorescence microscopy.

Amyloid fibrils are fibrillar aggregates of denatured proteins associated with a large number of amyloidoses. The formation of amyloid fibrils has been considered to occur by nucleation and elongation. Real-time imaging of the elongation as well as linear morphology of amyloid fibrils suggests that all elongation events occur at the growing ends of fibrils. On the other hand, we suggested that monomers also bind to the lateral sides of preformed fibrils during the seed-dependent elongation, diffuse to the growing ends, and finally make further conformation changes to the mature amyloid fibrils. To examine lateral binding during the elongation of fibrils, we used islet amyloid polypeptide (IAPP), which has been associated with type II diabetes, and prepared IAPP modified with the fluorescence dye, Alexa532. By monitoring the elongation process with amyloid specific thioflavin T and Alexa532 fluorescence, we obtained overlapping images of the two fluorescence probes, which indicated lateral binding. These results are similar to the surface diffusion-dependent growth of crystals, further supporting the similarities between amyloid fibrillation and the crystallization of substances.