Comparison of step-count outcomes across seven different activity trackers: a free-living experiment with young and older adults.

BACKGROUND: There are now many different types of activity trackers, including pedometers and accelerometers, to estimate step counts per day. Previous research has extensively examined step-count measurements using activity trackers across various settings while simultaneously wearing different devices.; however, older adults frequently display distinct walking patterns and gait speeds compared to younger adults. This study aimed to compare the step-count between older and younger adults by having them simultaneously wear seven different activity trackers in free-living experiments. METHODS: This study included 35 younger adults (21-43 yrs) and 57 physically independent older adults (65-91 yrs). All participants simultaneously wore one pedometer and six activity trackers: ActiGraph GT3X + Wrist and Hip, Omron Active Style Pro HJA-350IT, Panasonic Actimarker, TANITA EZ-064, Yamasa TH-300, and Yamasa AS-200 for seven days. A regression equation was also used to assess inter-device compatibility. RESULTS: When comparing wrist-worn ActiGraph to the six hip-worn activity trackers, the wrist-worn ActiGraph consistently recorded step counts over 4,000 steps higher than hip-worn activity trackers in both groups (range, 3000-5000 steps). Moreover, when comparing the ActiGraph worn on the wrist to that worn on the hip, the proportion was higher among older adults compared to younger ones (younger: 131%, older: 180%). The Actimarker recorded the highest average step counts among six hip-worn devices, with 8,569 ± 4,881 overall, 9,624 ± 5,177 for younger adults, and 7,890 ± 4,562 for older adults. The difference between the hip-worn ActiGraph and Active Style Pro was just about 70 steps/day overall. The correlation among all devices demonstrated a very high consistency, except for the wrist-worn ActiGraph (r = 0.874-0.978). CONCLUSIONS: Step counts recorded from seven selected consumer-based and research-grade activity trackers and one pedometer, except for the wrist-worn ActiGraph. showed a variation of approximately 1700 steps (range, 1265-2275 steps) steps for both groups, yet maintained a high correlation with each other. These findings will be valuable for researchers and clinicians as they compare step counts across different studies or representative surveys conducted globally.

Morning physical activity may be more beneficial for blood lipids than afternoon physical activity in older adults: a cross-sectional study.

BACKGROUND: The effect of differences in daily physical activity patterns on blood lipids has not been determined. This study examines the effects of the differences in free-living daily physical activity patterns (amount and intensity) on blood lipid levels in older adults. METHODS: This cross-sectional study included 51 older participants (71.8 ± 0.6 years, men = 8, women = 43). A triaxial accelerometer was used to assess physical activity patterns. The time from awakening to bedtime for each participant was used for group classification based on the amount (number of steps) and intensity (moderate-to-vigorous physical activity, MVPA) of physical activity. The morning step group (M Step) was defined as those who took more steps in the morning, and the afternoon step group (A Step) was defined as those who took more steps in the afternoon. The same method was used for MVPA (morning MVPA: M MVPA; afternoon MVPA: A MVPA). Blood samples were collected at the start of the study to determine blood lipid levels. RESULTS: Number of steps taken showed a trend toward lower low-density lipoprotein cholesterol (LDL-C) levels in the M Step group compared with the A Step group. The LDL/high-density lipoprotein (HDL) ratio was significantly lower in the M Step group than the A Step group (p < 0.05). The M MVPA group also had higher HDL-C levels and significantly lower LDL/HDL ratios than the A MVPA group (p < 0.05). CONCLUSIONS: These results suggest that compared with afternoon physical activity, daily morning physical activity (amount and intensity) is more effective in improving blood lipid levels.

A Combined Index Using the Mini-Mental State Examination and Lawton Index to Discriminate Between Clinical Dementia Rating Scores of 0.5 and 1: A Development and Validation Study.

Objective: To develop a combined index using cognitive function and instrumental activities of daily living (IADL) to discriminate between Clinical Dementia Rating (CDR) scores of 0.5 and 1 in the clinical setting, and to investigate its optimal cutoff values and internal and external validities.Methods: We included outpatients aged 65-89 years with CDR scores of 0.5 or 1. The optimal cutoff values and internal validity were verified using Japanese memory clinic-based datasets between September 2010 and October 2021 [National Center for Geriatrics and Gerontology (NCGG) datasets]. Cognitive function and IADL were assessed using the Mini-Mental State Examination (MMSE) and Lawton Index (LI), respectively. The optimal cutoff values were defined using the Youden Index. To verify internal validity, sensitivity and specificity were calculated using stratified 5-fold cross-validation. To verify external validity, sensitivity and specificity of the optimal cutoff values were assessed in the Organized Registration for the Assessment of dementia on Nationwide General consortium toward Effective treatment (ORANGE) Registry dataset between July 2015 and March 2022, which has multicenter clinical data.Results: A total of 800 (mean age, 77.53 years; men, 50.1%) and 1494 (mean age, 77.97 years; men, 43.3%) participants comprised the NCGG and ORANGE Registry datasets, respectively. The optimum cutoff values for men and women were determined as MMSE < 25 and LI < 5 and MMSE < 25 and LI < 8, respectively; such a combined index showed good discriminative performance in internal (sensitivity/specificity: men, 92.50/73.52; women, 88.57/65.65) and external validities (men, 81.43/77.62; women, 77.64/74.67).Conclusion: The index developed is useful in discriminating between CDR scores of 0.5 and 1 and should be applicable to various settings, such as memory clinics and clinical research.

Predictors of Water Turnover in Older Adults: A Doubly Labeled Water- and Triaxial Accelerometer-Based Study.

BACKGROUND: Water is one of the most essential nutrients for life. The water turnover (WT), total body water (TBW), and total energy expenditure (TEE) can be measured using the doubly labeled water (DLW) method. WT and TBW are lower in older adults than in young adults, and the former are susceptible to dehydration, necessitating to identify predictors of the WT in older adults. OBJECTIVES: The current study aimed to examine the association between WT and physical activity, physical function, and body composition in Japanese adults aged ≥65 y and identify predictors for WT in this population. METHODS: This study enrolled 133 older adults (women, n = 61; men, n = 72) aged 65-88 y. WT, TBW, TEE, fat-free mass (FFM), and percent body fat (%Fat) were determined using the DLW method. The fitness age score (FAS) was obtained from 5 physical fitness tests. Physical activity and the step count were assessed using a previously validated triaxial accelerometer. Multiple regression analyses were performed with WT as the dependent variable. RESULTS: WT was positively associated with weight, physical activity level (PAL), moderate-vigorous physical activity, and TEE, and negatively associated with sedentary behavior. We examined potential predictors for WT using age, sex, height, weight, FFM, %Fat, TEE, PAL, and FAS in older Japanese adults. CONCLUSIONS: Our results confirmed that age, sex, weight, FFM, TEE, and PAL are the potential predictors of WT in older Japanese adults aged ≥65 y.

Factors Influencing Life Space Mobility in Cancer Survivors Following Hematopoietic Stem Cell Transplantation - Physical Function, Depression, Fatigue, Neighborhood Walkability, and Employment Status.

BACKGROUND/OBJECTIVE: The level of physical activity in the daily lives of cancer survivors following hematopoietic stem cell transplantation (HSCT) is crucial for maintaining their physical and mental health. Considering that life space mobility (LSM) may limit physical activity, maintaining and expanding LSM is particularly essential for post-HSCT survivors. This study aimed to identify factors influencing LSM in post-HSCT survivors. METHODS: Thirty cancer survivors after HSCT (14 women, mean age 52.0 ± 12.3 years, 196-3017 days post-HSCT) were included in this cross-sectional study. The assessment encompassed patient characteristics, employment status, life space (Life Space Assessment; LSA), physical function (handgrip strength, isometric knee extension strength, 5 chair standing test, walking speed), depression (Self-rating Depression Scale; SDS), fatigue (Cancer Fatigue Scale), and neighborhood walkability (Walk Score®). The association between LSA and each factor was compared by correlation analysis. Subsequently, multiple regression analysis was conducted, with LSA as the dependent variable and independent variables being outcome measures exhibiting a significant correlation with LSA. RESULTS: Variables significantly correlated with LSA included SDS (r =-0.65, p < .01), employment status (r=-0.60, p < .01), handgrip strength (r = 0.43, p = .02), and isometric knee extension strength (r = 0.40, p = .03). Results of multiple regression analysis show that SDS (ß = -0.53, p < .01), employment status (ß = 0.48, p < .01), and isometric knee extension strength (ß = 0.27, p = .02) were significantly associated with LSA (R2 = 0.74). CONCLUSION: Depression, employment status, and isometric knee extension strength were identified as factors related to LSM in post-HSCT survivors.

Behavioral and psychological symptoms of dementia and mortality risk among people with cognitive impairment: an 8-year longitudinal study from the NCGG-STORIES.

BACKGROUND: Behavioral and psychological symptoms of dementia (BPSD) are common among people with dementia from the early stages and can appear even in mild cognitive impairment (MCI). However, the prognostic impact of BPSD is unclear. This study examined the association between BPSD and mortality among people with cognitive impairment. METHODS: This longitudinal study involved 1,065 males and 1,681 females (mean age: males = 77.1 years; females = 78.6 years) with MCI or dementia diagnosis, from the National Center for Geriatrics and Gerontology-Life Stories of People with Dementia (NCGG-STORIES), a single-center memory clinic-based cohort study in Japan that registered first-time outpatients from 2010-2018. Information about death was collected through a mail survey returned by participants or their close relatives, with an up to 8-year follow-up. BPSD was assessed using the Dementia Behavior Disturbance Scale (DBD) at baseline. RESULTS: During the follow-up period, 229 (28.1%) male and 254 (15.1%) female deaths occurred. Cox proportional hazards regression analysis showed that higher DBD scores were significantly associated with increased mortality risk among males, but not females (compared with the lowest quartile score group, hazard ratios [95% confidence intervals] for the highest quartile score group = 1.59 [1.11-2.29] for males and 1.06 [0.66-1.70] for females). Among the DBD items, lack of interest in daily living, excessive daytime sleep, and refusal to receive care had a higher mortality risk. CONCLUSIONS: The findings suggest a potential association between BPSD and poor prognosis among males with cognitive impairment.

Impact of Type 2 Diabetes and Glycated Hemoglobin Levels Within the Recommended Target Range on Mortality in Older Adults With Cognitive Impairment Receiving Care at a Memory Clinic: NCGG-STORIES.

OBJECTIVE: To determine the impact of type 2 diabetes and glycated hemoglobin (HbA1c) levels within the recommended target range according to the Japan Diabetes Society/Japan Geriatrics Society Joint Committee on mortality in older adults with cognitive impairment. RESEARCH DESIGN AND METHODS: This retrospective cohort study included 1,528 and 468 patients aged ≥65 years without and with type 2 diabetes, respectively, who were visiting a memory clinic. The 468 patients with type 2 diabetes were divided into three groups (within, above, and below the target range) based on their HbA1c levels, cognitive function, ability to perform activities of daily living, and medications associated with a high risk of hypoglycemia. The impact of diabetes and HbA1c levels on mortality was evaluated using Cox proportional hazards models. RESULTS: Over a median follow-up period of 3.8 years, 353 patients (17.7%) died. Compared with individuals without type 2 diabetes, HbA1c levels above (hazard ratio [HR] 1.70, 95% CI 1.08-2.69) and below (HR 2.15, 95% CI 1.33-3.48) the target range were associated with a higher risk of death; however, HbA1c levels within the target range were not (HR 1.02, 95% CI 0.77-1.36). CONCLUSIONS: HbA1c levels above and below the target range were associated with a higher risk of mortality, whereas patients with HbA1c levels within the target range did not exhibit a higher risk of mortality than individuals without type 2 diabetes. These results provide empirical support for the current target ranges among older adults with cognitive impairment.

Impact of Concurrent Visual and Hearing Impairment on Incident Alzheimer's Disease: The LIFE Study.

Background: The prevalence of Alzheimer's disease (AD) is increasing in Japan due to population aging. The association between sensory impairment and incident AD remains unclear. Objective: This study aimed to investigate the impact of sensory impairment on incident AD. Methods: We analyzed residents of five municipalities participating in the Longevity Improvement & Fair Evidence (LIFE) Study. The participants comprised individuals who had newly applied for long-term care needs certification between 2017 and 2022 and had no cognitive impairment upon application or AD diagnosis within the preceding six months. Participants were classified according to sensory impairment status: visual impairment (VI), hearing impairment (HI), neither sensory impairment (NSI), and dual sensory impairment (DSI). The month succeeding the certification application was set as the index month, and the interval from that month until AD onset was assessed. Multivariable Cox proportional hazards analysis was performed to calculate the risk of AD onset according to sensory impairment status while adjusting for sex, age, dependence level, self-reliance level, and comorbidities. Results: Among 14,186 participants, we identified 1,194 (8.4%) who developed AD over a median follow-up period of 22.6 months. VI and HI only were not associated with incident AD. However, DSI conferred a significantly higher risk (HR: 1.6, CI: 1.1-2.2, p = 0.008) of AD onset than NSI. Conclusions: Individuals with concurrent DSI have a higher risk of developing AD than those with single or NSI. Preventing and treating sensory impairment may not only improve functional outcomes, but could also help to reduce the future risk of AD.

Data resource profile: Exercise habits, step counts, and sedentary behavior from the National Health and Nutrition Survey in Japan.

The National Health and Nutrition Survey consistently assesses the prevalence of exercise habits, step counts, and sedentary behaviors in a strategically selected random sample of the Japanese population. The aim of this study was to provide descriptive epidemiological data on the average frequency of exercise habits, daily step counts, and sedentary behavior among Japanese adults from 2003 to 2019 using the National Health and Nutrition Survey database in Japan. Data were obtained from electronically available aggregate reports on the official survey website. To prepare for the third term of Health Japan 21, scheduled to start in 2024, we summarized population-level trends in exercise habits, step counts, and sedentary behavior among Japanese adults. The results could improve our understanding of trends in physical activity with respect to age and gender, providing a basis for public health monitoring and policy-making.

Association between abdominal adiposity and cognitive decline in older adults: a 10-year community-based study.

OBJECTIVES: This study aimed to investigate the association between abdominal adiposity and change in cognitive function in community-dwelling older adults. DESIGN, SETTING, AND PARTICIPANTS: This longitudinal study included older adults aged ≥60 years without cognitive impairment who participated in the National Institute for Longevity Sciences - Longitudinal Study of Aging. MEASUREMENTS: Cognitive function was evaluated biennially using the Mini-Mental State Examination (MMSE) over 10 years. Waist circumference (WC) was measured at the naval level, and subcutaneous fat area (SFA) and visceral fat area (VFA) were assessed using baseline computed tomography scans. WC, SFA, and VFA areas were stratified into sex-adjusted tertiles. A linear mixed model was applied separately for men and women. RESULTS: This study included 873 older adults. In men, the groups with the highest levels of WC, SFA, and VFA exhibited a greater decline in MMSE score than the groups with the lowest levels (ß [95% confidence interval]: WC, -0.12 [-0.23 to -0.01]; SFA, -0.13 [-0.24 to -0.02]; VFA, -0.11 [-0.22 to -0.01]). In women, the group with the highest level of WC and SFA showed a greater decline in MMSE score than the group with the lowest level (WC, -0.12 [-0.25 to -0.01]; SFA, -0.18 [-0.30 to -0.06]), but VFA was not associated with cognitive decline. CONCLUSION: Higher WC, SFA, and VFA in men and higher WC and SFA in women were identified as risk factors for cognitive decline in later life, suggesting that abdominal adiposity involved in cognitive decline may differ according to sex.

Relationship between mortality and vitality in patients with mild cognitive impairment/dementia: An 8-year retrospective study.

AIM: The study aimed to investigate the association of vitality, as measured using the vitality index (Vix), with the survival outcomes of older adults with mild cognitive impairment (MCI) or dementia. METHODS: We analyzed data from 3731 patients in the National Center for Geriatrics and Gerontology - Life Stories of Individuals with Dementia cohort from July 2010 to September 2018. The main focus was to correlate Vix scores with the time from the initial visit to death. Vix was categorized into "moderately to severely impaired" (0-7 points), "mildly impaired" (8-9 points), and "normal" (10 points) groups. Survival outcomes were assessed using a Cox proportional hazards model, adjusted for various factors. We conducted a mediation analysis to evaluate the effect of body mass index (BMI), instrumental activities of daily living (IADL), and basic activities of daily living (BADL) on the association between vitality and mortality. Stratified analysis was also conducted for the Mini-Mental State Examination groups. RESULTS: We included 2740 patients with an average follow-up of 1315 days. The mortality rate was 15.7%. The Vix distribution was 16% at 0-7 points; 40%, 8-9 points; and 44%, 10 points. Patients in the "moderately to severely impaired" category, characterized by lower Vix scores, exhibited notably higher mortality rates. Mediation effects emphasized the significant roles of BMI, IADL, and BADL in influencing survival outcomes. CONCLUSIONS: Vitality significantly influences patient survival rates. The association between vitality and mortality seems to be mediated by IADL and BADL, which has significant clinical implications. Geriatr Gerontol Int 2024; 24: 221-228.

Association between regular physical activity and pneumonia-related hospitalization according to pneumococcal vaccination status: The VENUS study.

BACKGROUND: Little is known about the impact of physical activity (PA) and PPSV23 vaccination on pneumonia-related hospitalizations. This study examined the association between regular PA and pneumonia-related hospitalization according to PPSV23 vaccination status in older adults. METHODS: This retrospective cohort study was conducted using health checkup data, medical care claims data, and vaccination records from two Japanese municipalities. Residents aged ≥65 years who had undergone a health checkup between April 2016 and March 2021 were categorized into a PPSV23 vaccinated or unvaccinated cohort. Each cohort was further divided into a PA group and no PA group. The hazard ratio (HR) of PA for pneumonia-related hospitalization was calculated for each cohort while adjusting for sex, age, comorbidities, and metabolic syndrome. RESULTS: The vaccinated cohort comprised 16,295 participants (no PA: 5,139, PA: 11,156), and the unvaccinated cohort comprised 7,998 participants (no PA: 2,671, PA: 5,327). In the vaccinated cohort, the PA group had a significantly lower hazard for pneumonia-related hospitalization than the no PA group (adjusted HR: 0.58, P = 0.004). However, PA was not associated with pneumonia-related hospitalization in the unvaccinated cohort (adjusted HR: 0.70, P = 0.270). CONCLUSIONS: PA can reduce the risk of pneumonia-related hospitalization in vaccinated persons. Interventions that increase both vaccination rates and PA habits may help to reduce these hospitalizations in older adults.

Claims-based Frailty Index in Japanese Older Adults: A Cohort Study Using LIFE Study Data.

BACKGROUND: We aimed to assess whether the United States-developed Claims-based Frailty Index (CFI) can be implemented in Japanese older adults using claims data. METHODS: We used the monthly claims data and certification of long-term care (LTC) insurance data of residents from 12 municipalities from April 2014 to March 2019. The 12 months from first recording was defined as the "baseline period," and the time thereafter as the "follow-up period". Participants aged ≥65 years were included, and those with no certified LTC insurance or who died at baseline were excluded. New certification of LTC insurance and all-cause mortality during the follow-up period were defined as outcome events. CFI categorization consisted of three steps including: 1) using 12 months deficit-accumulation approach that assigned different weights to each of the 52 items; 2) the accumulated score to derive the CFI; and 3) categorizing the CFI as "robust" (<0.15), "prefrail" (0.15-0.24), and "frail" (≥0.25). Kaplan-Meier survival curves and Cox proportional hazard models were used to determine the association between CFI and outcomes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. RESULTS: There were 519,941 participants in total. After adjusting for covariates, the severe CFI category had a high risk of certification of LTC insurance (prefrail: HR 1.33; 95% CI, 1.27-1.39 and frail: HR 1.60; 95% CI, 1.53-1.68) and all-cause mortality (prefrail: HR 1.44; 95% CI, 1.29-1.60 and frail: HR 1.84; 95% CI, 1.66-2.05). CONCLUSION: This study suggests that CFI can be implemented in Japanese claims data to predict the certification of LTC insurance and mortality.

Pneumococcal vaccination coverage and vaccination-related factors among older adults in Japan: LIFE Study.

PURPOSE: To investigate individual and environmental vaccination-related factors among the older adults in Japan, using administrative data. METHODS: We conducted a cohort study and included people who reached the relevant age (≥65 years) for routine pneumococcal vaccination of older adults between April 2015 and March 2020. Monthly data of residents in the two municipalities from April 2014 to March 2020 and vaccination records from April 2015 to March 2020 were used. We defined five cohorts according to the year in which routine vaccinations were available. Each cohort was followed for a total of two years, with the first year being the "baseline period" and second year being the "vaccine follow-up period." Pneumococcal vaccination data was extracted from vaccination records at "first dose." Age, sex, socioeconomic status, comorbidities, hospital visit history, hospitalization history, Specific Health Check-ups participation, and information on contracted hospitals for pneumococcal vaccination were used as covariates. A multivariate logistic regression model was used to investigate the relationship between pneumococcal vaccination and vaccination-related factors. Odds ratios (OR) and 95 % confidence intervals (95 % CI) were calculated. RESULTS: Analysis included 17,991 patients. Vaccination coverage was 33.6 % for all subjects. Multivariate analysis found the following as significant vaccination-related factors: female (OR: 1.18, 95 % CI: 1.11-1.26), not low income (1.76, 1.17-2.76), hospital visits: ≥once/month (1.27, 1.19-1.35), and Specific Health Check-ups participation (2.10, 1.95-2.27). No significant results were found for hospitals that contracted pneumococcal vaccination. CONCLUSIONS: Individual factors, such as sex and Specific Health Check-ups participation, were found to be important factors affecting pneumococcal vaccination among older adults in Japan. Environmental factors, such as the characteristics of residential areas, should be evaluated in further investigations.

Effects of energy loads on energy and nutrient absorption rates and gut microbiome in humans: A randomized crossover trial.

OBJECTIVE: This study aimed to determine the effects of different energy loads on the gut microbiota composition and the rates of energy and nutrient excretion via feces and urine. METHODS: A randomized crossover dietary intervention study was conducted with three dietary conditions: overfeeding (OF), control (CON), and underfeeding (UF). Ten healthy men were subjected to each condition for 8 days (4 days and 3 nights in nonlaboratory and laboratory settings each). The effects of dietary conditions on energy excretion rates via feces and urine were assessed using a bomb calorimeter. RESULTS: Short-term energy loads dynamically altered the gut microbiota at the α-diversity (Shannon index), phylum, and genus levels (p < 0.05). Energy excretion rates via urine and urine plus feces decreased under OF more than under CON (urine -0.7%; p < 0.001, urine plus feces -1.9%; p = 0.049) and UF (urine -1.0%; p < 0.001, urine plus feces -2.1%; p = 0.031). However, energy excretion rates via feces did not differ between conditions. CONCLUSIONS: Although short-term overfeeding dynamically altered the gut microbiota composition, the energy excretion rate via feces was unaffected. Energy excretion rates via urine and urine plus feces were lower under OF than under CON and UF conditions.

Risk factors for progression of the severity of locomotive syndrome: A two-year longitudinal observational study.

BACKGROUND: The risk factors for progression of severity of locomotive syndrome (LS) remain unclear. METHODS: We conducted a longitudinal observational study of 1148 community-dwelling residents (median age, 68.0 years old; 548 males, 600 females) from 2016 to 2018. LS was assessed by the 25-question Geriatric Locomotive Function Scale (GLFS-25), and total scores of ≤6 points, 7-15 points, 16-23 points, and ≥24 points were diagnosed as non-LS, LS-1, LS-2, and LS-3, respectively. If the LS severity in 2018 was higher than in 2016, the case was defined as progression of LS severity; otherwise, it was defined as non-progressive LS. We compared the age, gender, body mass index, smoking status, alcohol consumption, living situation, car use, chronic musculoskeletal pain, comorbidities, metabolic syndrome, physical activity, and LS severity in 2016 between the progression and non-progression groups. Furthermore, a multivariate logistic regression analysis was performed to elucidate the risk factors for progression of LS severity. RESULTS: Participants in the progression group had a significantly older age, a lower rate of car use, a higher rate of low back pain, a higher rate of hip pain, a higher rate of knee pain, a higher GLFS-25 total score, and a higher rate of LS-2 than those in the non-progression group. The multivariate logistic regression analysis revealed that older age, female gender, higher body mass index (≥25.0 kg/m2), presence of low back pain, and presence of hip pain were risk factors for the progression of LS within two years. CONCLUSIONS: To prevent the progression of LS severity, related prophylaxis strategies should be implemented, especially for individuals with the above-mentioned characteristics. Further longitudinal studies with a longer observation period are necessary.

Association of skeletal muscle function, quantity, and quality with gut microbiota in Japanese adults: A cross-sectional study.

AIM: The gut microbiota has emerged as a new intervention target for sarcopenia. Prior studies in humans have focused on the association between gut microbiota and skeletal muscle quantity, while the evidence on muscle function and quality is lacking. This study aimed to identify gut microbiota genera associated with skeletal muscle function, quantity, and quality in a general population of Japanese adults. METHODS: This cross-sectional study included 164 participants aged 35-80 years, women and men recruited from urban areas of Japan. Fecal samples were collected and analyzed using 16S rRNA gene amplicon sequencing. Skeletal muscle function was measured using handgrip strength and leg extension power (LEP), while skeletal muscle mass was estimated using bioelectrical impedance analysis. Phase angle was used as a measure of skeletal muscle quality. Multivariate linear regression analysis stratified by age group was used to examine the association between the dominant genera of the gut microbiota and skeletal muscle variables. RESULTS: A significant association was found between Bacteroides and Prevotella 9 with LEP only in the ≥60 years group. When both Bacteroides and Prevotella 9 were included in the same regression model, only Bacteroides remained consistently and significantly associated with LEP. No significant associations were observed between skeletal muscle mass, handgrip strength, and phase angle and major gut microbiota genera. CONCLUSIONS: In this study, we observed a significant positive association between Bacteroides and leg muscle function in older adults. Further studies are required to elucidate the underlying mechanisms linking Bacteroides to lower-extremity muscle function. Geriatr Gerontol Int 2024; 24: 53-60.

Developing a predictive model for mortality in patients with cognitive impairment.

OBJECTIVES: We developed a predictive model for all-cause mortality and examined the risk factors for cause-specific mortality among people with cognitive impairment in a Japanese memory clinic-based cohort (2010-2018). METHODS: This retrospective cohort study included people aged ≥65 years with mild cognitive impairment or dementia. The survival status was assessed based on the response of participants or their close relatives via a postal survey. Potential predictors including demographic and lifestyle-related factors, functional status, and behavioral and psychological status were assessed at the first visit at the memory clinic. A backward stepwise Cox regression model was used to select predictors, and a predictive model was developed using a regression coefficient-based scoring approach. The discrimination and calibration were assessed via Harrell's C-statistic and a calibration plot, respectively. RESULTS: A total of 2610 patients aged ≥65 years (men, 38.3%) were analyzed. Over a mean follow-up of 4.1 years, 544 patients (20.8%) died. Nine predictors were selected from the sociodemographic and clinical variables: age, sex, body mass index, gait performance, physical activity, and ability for instrumental activities of daily living, cognitive function, and self-reported comorbidities (pulmonary disease and diabetes). The model showed good discrimination and calibration for 1-5-year mortality (Harrell's C-statistic, 0.739-0.779). Some predictors were specifically associated with cause-specific mortality. CONCLUSIONS: This predictive model has good discriminative ability for 1- to 5-year mortality and can be easily implemented for people with mild cognitive impairment and all stages of dementia referred to a memory clinic.

Assessment of Lumbar Spinal Stenosis as a Risk Factor for Development of Sleep Disorder: The Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS).

Purpose: Insomnia has been reported to coexist with various musculoskeletal disorders. Although lumbar spinal stenosis (LSS) is the most frequently operated on spinal disease, the causal relationship between LSS and development of sleep disorders remains unclear due to lack of longitudinal studies. This study aimed to determine whether LSS was a risk factor for developing new sleep disorders, primarily insomnia, using a prospective cohort of community residents. Patients and Methods: This study was a prospective cohort study. Participants aged ≥65 years from the "Locomotive Syndrome and Health Outcomes in Aizu Cohort Study (LOHAS)" conducted in 2008 formed our study population. LSS was diagnosed using the self-administered, self-reported history questionnaire, a validated diagnostic support tool for LSS. Sleep disorder was investigated using a questionnaire during the 2-year follow-up. The impact of LSS on sleep disorder onset was analyzed after adjusting for potential confounders, such as age, sex, obesity, hypertension, diabetes, depression, and smoking habits, using propensity score matching. Results: Of the 489 participants who were followed up for two years, 38 (7.8%) had newly developed a sleep disorder in 2010. After adjusting for confounding factors, a comparison of 133 participants each in the control and LSS groups showed significantly higher frequency of new-onset sleep disorders (19 [14.3%] in the LSS group versus 6 [4.5%] in the control group). Conclusion: LSS was found to be an independent risk factor for sleep disorders.