Effects of Radio-Taiso on Health-Related Quality of Life in Older Adults with Frailty: A Randomized Controlled Trial.

BACKGROUND: Radio-Taiso could be a sustainable public health strategy for maintaining quality of life (QoL) in older adults with frailty. This study aimed to investigate whether Radio-Taiso provided greater benefits for health-related quality of life (HR-QoL) and to identify the mechanisms underlying the effectiveness in this population. METHODS: A 12-week randomized controlled trial enrolled 226 older Japanese adults with pre-frailty or frailty, assessed using the modified frailty phenotype. Participants were randomly allocated to the intervention (Radio-Taiso + nutrition program) or control (nutrition program) groups. The Radio-Taiso program comprised five 60-min group sessions and daily practice at the participants' homes. The primary outcome was the change in the mental domain of HR-QoL, assessed using the SF-36®. The secondary outcomes included six physical fitness items and exercise self-efficacy. RESULTS: Overall, 104 and 105 participants in the intervention and control groups, respectively, were analyzed based on the intention-to-treat principle. The median (interquartile range) daily practice rate of Radio-Taiso was 94.1% (73.2-98.8%). Although general linear models adjusted for baseline values and allocation stratification factors showed that the intervention group obtained greater benefits (adjusted mean differences [95% confidence intervals]) in the up-and-go (0.3 [0.1, 0.6] s), 2-min step-in-place (-3.2 [-6.2, -0.2] steps) tests, and exercise self-efficacy scale (-1.4 [-2.6, -0.1] points) than the control group, there were no group differences in changes in the mental domain score of HR-QoL. CONCLUSIONS: Radio-Taiso provided greater benefits for agility/dynamic balance, aerobic endurance, and exercise self-efficacy in older adults with frailty; however, these changes do not improve HR-QoL.

Aging trajectories of subscales in higher-level functional capacity among community-dwelling older Japanese adults: the Otassha study.

BACKGROUND: Maintaining higher-level functional capacity is important for independent living in older age. The aging trajectory of the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) has three patterns; however, the subscale patterns are unclear. AIMS: This study aimed to clarify the aging trajectory patterns of the TMIG-IC subscales among community-dwelling older Japanese. METHODS: Participants were 3,169 community-dwelling older Japanese who participated in the 2012-2022 mail survey of the Otassha study. The aging trajectory patterns of the TMIG-IC total and subscale scores for those aged 65-90 years were identified using group-based trajectory modeling. Further, the combination frequency of the subscale trajectory patterns was determined. RESULTS: Three patterns were identified: early-onset decreasing, late-onset decreasing, and high-stable. DISCUSSION: The instrumental activities of daily living (IADL) trajectory was maintained until approximately 80 years of age; however, chronic disease prevailed the most in the early-onset decreasing pattern. The early-onset decreasing pattern of intellectual activity (IA) was present in 25% of participants, showing impaired IA from 65 years of age. The late-onset decreasing pattern of social roles (SR) was present in 30% of participants, showing a sharp decline compared to other subscales. For many people, the patterns of decrease in SR and IA overlapped. CONCLUSIONS: To maintain higher-level functional capacity, interventions that include disease management and prevention of decline in IADL and increase the awareness of the social support provided throughout old age and interventions for people with an early decline in IA should be implemented.

Association of the COVID-19 pandemic with changes in objectively measured sedentary behaviour and adiposity.

BACKGROUND: Several studies have reported that the coronavirus disease (COVID-19) pandemic has increased sedentary behaviour and obesity; however, these analyses used self-reported data, and the association between sedentary behaviour and visceral fat and adipocytokines during the COVID-19 pandemic remains unclear. We aimed to investigate the association of the COVID-19 pandemic with objectively measured sedentary behaviour and these obesity-related factors. METHODS: Longitudinal analysis was conducted on 257 Japanese participants who underwent health check-ups in 2018 before and in 2020 during the COVID-19 pandemic. For both time points, sedentary behaviour was measured using an accelerometer for at least 7 days, visceral fat area (VFA) was measured using abdominal bioelectrical impedance analysis, and blood adiponectin level was measured using latex agglutination turbidimetric immunoassay. Multiple linear regression was performed to determine the association between sedentary behaviour and these outcomes. RESULTS: Compared with data in 2018, sedentary behaviour and VFA were significantly increased (P < 0.001, P = 0.006) whereas adiponectin level was significantly decreased (P < 0.001) in 2020. Increased sedentary behaviour was significantly associated with an increase in VFA (ß = 3.85, 95% CI 1.22-6.49, P = 0.004) and a decrease in adiponectin level (ß = -0.04, 95% CI -0.06 to -0.01, P = 0.005). However, the association of sedentary behaviour with adiponectin level was not significant after considering the effects of VFA. CONCLUSIONS: The COVID-19 pandemic was associated with objectively measured sedentary behaviour and obesity-related factors in Japanese adults. Additionally, an increase in sedentary behaviour was associated with an increase in VFA, whereas the association of sedentary behaviour with adiponectin was partly mediated by VFA. These results suggest that avoiding increasing sedentary time is important to prevent visceral adiposity thereby ameliorating adiponectin, especially during behavioural limitations such as the COVID-19 pandemic.

Vitamin K insufficiency predicts incidence of frailty in community-dwelling older adults: The Otassha Study.

INTRODUCTION: Vitamin K is a fat-soluble vitamin discovered as an essential factor for blood coagulation. It is suggested that vitamin K can benefit several aging-related diseases, including osteoporosis, osteoarthritis, and dementia. We previously reported the cross-sectional association of vitamin K insufficiency with frailty in community-dwelling older adults. MATERIALS AND METHODS: In October 2020, a health examination of community-dwelling older adults (The Otassha Study) was performed, including frailty evaluation and blood tests. We used a ucOC and OC ratio (ucOC/OC) to indicate vitamin K insufficiency. One year later, we conducted a follow-up evaluation of frailty on 518 people who were not frail at baseline. The serum ucOC/OC at the baseline examination was divided into quartiles (Q1, Q2, Q3, and Q4). Odds ratio (OR) and 95% confidence interval (CI) were calculated using multivariate binary logistic regression for each quartile of ucOC/OC to determine the risk of incident frailty in the follow-up study, with the lowest quartile (Q1) as the reference. RESULTS: Among the 518 older adults who were not frail at baseline, 66 people (12.7%) became frail in the follow-up study. In the multivariate binary logistic regression analysis, setting the lowest quartile of ucOC/OC (Q1) as a reference, the OR of the incident frailty in the highest quartile (Q4) was 2.53 (95% CI 1.07, 4.92) which was significantly different from Q1. CONCLUSION: The findings of this longitudinal study suggest that vitamin K insufficiency has nutritional importance in predicting the future incidence of frailty in the Japanese older adult population.

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.

Association of Knee Extensor Muscle Strength and Cardiorespiratory Fitness With Bone Stiffness in Japanese Adults: A Cross-sectional Study.

BACKGROUND: Knee extensor muscle strength and cardiorespiratory fitness (CRF) are major components of physical fitness. Because the interactive association of knee extensor muscle strength and CRF with bone health remains unclear, we aimed to investigate such association in Japanese adults. METHODS: Altogether, 8,829 Japanese adults (3,731 men and 5,098 women) aged ≥45 years completed the maximum voluntary knee extension test, submaximal exercise test, medical examination, and a questionnaire on lifestyle habits. Using an osteo-sono assessment index, low bone stiffness tendency was defined as 80% under the young-adults mean. Multivariable odds ratios (ORs) and 95% confidence intervals (CIs) were calculated after confounder adjustment. RESULTS: Overall, 542 men (14.5%) and 978 women (19.2%) had low bone stiffness tendency. We observed an inverse association between muscle strength and low bone stiffness tendency after adjustment for CRF in both sexes (P for linear trend <0.001). Compared with the lowest CRF, the multivariable ORs for low bone stiffness tendency in the highest CRF were 0.47 (95% CI, 0.36-0.62) for men and 1.05 (95% CI, 0.82-1.35) for post-menopausal women (P < 0.001 and P = 0.704, respectively). No interactive association between muscle strength and CRF for low bone stiffness tendency existed in both sexes and irrespective of menopausal status. CONCLUSION: Knee extensor muscle strength and CRF were associated additively, not synergistically, with bone health. Maintaining high levels of both physical fitness components may improve musculoskeletal health in the cohort. The relationship between physical fitness and bone status should be longitudinally investigated in the future.

Design and experimental evaluation of enhanced diffraction efficiency of lanthanum-based material coated laminar-type gratings in the boron K-emission region.

Numerical and experimental studies have been performed to evaluate the enhancement of diffraction efficiency of diffraction gratings around B $K$-emission by overcoating lanthanum series layers on conventional metal-coated laminar-type gratings. We propose an optical design method based on the concept of spectral flux given by collection efficiency and diffraction efficiency. A diffraction grating with a small angle of incidence provides an advantage to soft x-ray spectrographs because it collects the emission at a larger solid angle compared to that of conventional grazing incidence diffraction gratings. Numerical calculations indicated that La and ${\rm{La}}{{\rm{F}}_3}$ were promising as overcoating materials on a laminar-type Ni-coated diffraction grating, and we performed an experimental study using ${\rm{La}}{{\rm{F}}_3}$ and La/C overcoatings, considering their producibility and durability. The diffraction efficiencies were measured using a reflectometer at a synchrotron facility. The diffraction efficiencies observed at 183.4 eV were 29.4% and 34.3% at angles of incidence of 85.1° and 84.9° for ${\rm{Ni}}/{\rm{La}}{{\rm{F}}_3}$ and Ni/La/C gratings, respectively.

Nursing Students' Practicums during the COVID-19 Crisis and the Effect on Infection-Prevention Behavior in Students: A Mixed-Method Approach.

Background and Objectives: The coronavirus disease pandemic is ongoing. Infection-prevention measures in nursing education (practicum) are essential. However, there are few studies on infection-prevention behaviors among nursing students participating in practicums. We aimed to clarify the effect of practicums during the coronavirus disease crisis on infection-prevention behavior in Japanese nursing students. Materials and Methods: We conducted semi-structured interviews with 13 third-year nursing students in Osaka City within one week of their clinical placement training. From the results of the interview analysis, we compiled a questionnaire and surveyed 90 third-year students. We conducted qualitative and quantitative analyses. We used descriptive statistics for the quantitative analysis and the chi-squared test for binary variables. Results: From the qualitative analysis, we identified five categories regarding the awareness of infection-prevention measures: , , , , and . In the quantitative analysis, the practicum students who attended at least three pre-practicum orientations continued wearing masks during lunch breaks and avoided the three Cs. Conclusions: Students could recall the knowledge and experiences gained from pre-practicum orientations/practicums. This experience created a new awareness of infection-prevention and change of infection-prevention behavior. Infection-prevention education using practicums is important for infection-prevention behavior during this pandemic. However, there should be a much larger-scale study to support these findings in the future.

Physical Fitness Levels among Colon Cancer Survivors with a Stoma: A Preliminary Study.

Background and Objectives: Stoma surgery is linked to reduced physical activity in colon cancer survivors and leads to decreased physical fitness, activity of daily living dysfunction, and poorer quality of life. However, few studies have investigated the physical fitness levels of colon cancer survivors living with stomas. This study aimed to compare the physical fitness levels of colon cancer survivors with stomas and healthy adults, assessing them in a variety of dimensions (e.g., strength and flexibility) and in terms of physical fitness age (PFA), an integrated index of overall fitness. Materials and Methods: The study population consisted of 17 colon cancer survivors with (stoma group) and 20 healthy adults without (control group) a stoma. Physical fitness was assessed using a battery of five tests: repeated back-and-forth steps, 30-s chair stand, chair sit-and-reach, grip strength, and single-leg balance with eyes closed. Respective performance values were converted into PFA, which was compared between the stoma and control groups. Fitness indicators were compared between groups by analysis of covariance, and PFA and chronological age (CA) by paired t-tests. Results: The mean ages (±standard deviation) of the stoma and control groups were 74.1 ± 7.9 and 73.5 ± 7.1 years, respectively. Colon cancer survivors with stomas had poorer lower limb muscular strength, endurance, and flexibility than controls. In the stoma group, the marginal mean (±standard error) PFA was calculated to be 82.5 ± 3.7 years, significantly higher than the CA and PFA of the control group (69.6 ± 3.9 years). Conclusions: Colon cancer survivors with stomas have lower physical fitness levels than healthy adults, with apparent deficits in lower limb flexibility, muscular strength, and endurance. Our findings demonstrated the need for exercise interventions in this population, focusing on these dimensions of fitness. However, our results should be corroborated by means of a larger-scale comparison in future studies.

Simultaneous Validation of Seven Physical Activity Questionnaires Used in Japanese Cohorts for Estimating Energy Expenditure: A Doubly Labeled Water Study.

BACKGROUND: Physical activity questionnaires (PAQs) used in large-scale Japanese cohorts have rarely been simultaneously validated against the gold standard doubly labeled water (DLW) method. This study examined the validity of seven PAQs used in Japan for estimating energy expenditure against the DLW method. METHODS: Twenty healthy Japanese adults (9 men; mean age, 32.4 [standard deviation {SD}, 9.4] years, mainly researchers and students) participated in this study. Fifteen-day daily total energy expenditure (TEE) and basal metabolic rate (BMR) were measured using the DLW method and a metabolic chamber, respectively. Activity energy expenditure (AEE) was calculated as TEE - BMR - 0.1 × TEE. Seven PAQs were self-administered to estimate TEE and AEE. RESULTS: The mean measured values of TEE and AEE were 2,294 (SD, 318) kcal/day and 721 (SD, 161) kcal/day, respectively. All of the PAQs indicated moderate-to-strong correlations with the DLW method in TEE (rho = 0.57-0.84). Two PAQs (Japan Public Health Center Study [JPHC]-PAQ Short and JPHC-PAQ Long) showed significant equivalence in TEE and moderate intra-class correlation coefficients (ICC). None of the PAQs showed significantly equivalent AEE estimates, with differences ranging from -547 to 77 kcal/day. Correlations and ICCs in AEE were mostly weak or fair (rho = 0.02-0.54, and ICC = 0.00-0.44). Only JPHC-PAQ Short provided significant and fair agreement with the DLW method. CONCLUSIONS: TEE estimated by the PAQs showed moderate or strong correlations with the results of DLW. Two PAQs showed equivalent TEE and moderate agreement. None of the PAQs showed equivalent AEE estimation to the gold standard, with weak-to-fair correlations and agreements. Further studies with larger sample sizes are needed to confirm these findings.

Performance of a flat-field grating spectrometer for tender x-ray emission spectroscopy.

A flat-field grating spectrometer for tender x-ray emission spectroscopy has been developed. The grating has been coated with an aperiodic Ni/C multilayer that improves the diffraction efficiency in the range 1-3.5 keV at a constant angle of incidence. The aperiodic layer structure originates from the topmost bilayer with a larger thickness compared to other Ni/C bilayers. The performance of the spectrometer has been evaluated by measuring characteristic x rays such as the L series emitted from a Cu(In,Ga)Se2-based thin-film solar cell specimen. It is shown that the Lα1,2 x-ray emission spectra of Cu, In, Ga, and Se can be clearly simultaneously observed in the range from 0.9 to 3.3 keV, and the linewidths are 4.9, 26.1, 4.6, and 6.1 eV, respectively, corresponding to a spectral resolution of 100-300.

Percentage-Method Improves Properties of Workers' Sitting- and Walking-Time Questionnaire.

BACKGROUND: Does asking for the percentage of time spent sitting during work (P-method) instead of asking for the absolute length of time spent sitting (T-method) improve properties of the workers' sitting- and walking-time questionnaire (WSWQ)? The purpose of this study was to investigate whether questioning technique influences test-retest reliability and criterion validity of the WSWQ. METHODS: Sixty-five Japanese workers completed each version of the WSWQ in random order. Both questionnaires assessed quantities of time spent sitting or walking (including standing) during work time, non-working time on a workday, and anytime on a non-workday. Participants wore the thigh-worn inclinometer (activPAL) as criterion measure. Intraclass correlation coefficients (ICC) and Spearman's ρ were used for the analyses. RESULTS: For all three domains, values of reliability and validity with the P-method tended to be higher than with the T-method: ICC values ranged from 0.48-0.85 for the T-method and from 0.71-0.85 for the P-method; Spearman's ρ values ranged from 0.25-0.58 for the T-method and from 0.42-0.65 for the P-method. The validities with both methods on a workday (0.51-0.58 for the T-method and 0.56-0.65 for the P-method) were higher than validities on a non-workday (0.25-0.45 for the T-method and 0.42-0.60 for the P-method). In post-survey interviews, 48 participants (77%) chose the P-method as their preferred questioning style. CONCLUSIONS: The study revealed that the P-method WSWQ had better reliability, validity, and ease of answering than the T-method, suggesting that the P-method can improve properties of the WSWQ and consequently advance the quality of epidemiological surveys in this field.

Objectively measured night-to-night sleep variations are associated with body composition in very elderly women.

This cross-sectional study examined the association between objectively measured sleep patterns and body composition in very elderly community-dwelling women. Participants included 191 community-dwelling adults aged ≥ 80 years (mean age: 83.4 ± 2.6 years; age range: 80-92 years). Sleep and physical activity were monitored via accelerometer (ActiGraph GT3X+) during at least five consecutive 24-h periods. Night-to-night sleep pattern variability across all nights of recording was assessed using standard deviations (SDs). Body composition was assessed using dual-energy X-ray absorptiometry. Simple and multivariable linear regression analyses were performed. The mean number of nights with usable actigraphy data was 7.3 ± 1.3. On average, participants went to bed at 22:57 hours (SD: 1.11 h) and rose from bed at 6:27 hours (SD: 1.01 h). Night-to-night bedtime, sleep duration and sleep timing mid-point variations correlated slightly with the percentage body fat and percentage lean mass (P < 0.05). Multiple linear regression analysis revealed significant associations of night-to-night bedtime variations and inconsistent sleep-wake patterns with all body composition indices after adjusting for potential confounding factors, including mean nightly sleep duration, self-reported nap duration and daily physical activity. After further adjusting for night-to-night wake time, sleep timing mid-point and sleep duration variations, greater bedtime variability remained associated significantly with all body composition indices except lean/fat mass ratio. Inconsistent sleep-wake patterns were associated independently with an increased fat mass and decreased lean mass among very elderly women. These findings suggest that in most elderly individuals, sleep patterns might be an important modifiable factor associated with obesity and sarcopenia development.

Lifestyle modification decreases arterial stiffness in overweight and obese men: dietary modification vs. exercise training.

Obesity and increased arterial stiffness are independent risk factors for cardiovascular disease. Arterial stiffness is increased in obese individuals than in age-matched nonobese individuals. We demonstrated that dietary modification and exercise training are effective in reducing arterial stiffness in obese persons. However, the differences in the effect on arterial stiffness between dietary modification and exercise training are unknown. The purpose of the current study was to compare the effect of dietary modification and aerobic exercise training on arterial stiffness and endothelial function in overweight and obese persons. Forty-five overweight and obese men (48 ± 1 year) completed either a dietary modification (well-balanced nutrient, 1680 kcal/day) or an exercise-training program (walking, 40-60 min/day, 3 days/week) for 12 weeks. Before and after the intervention, all participants underwent anthropometric measurements. Arterial stiffness was measured based on carotid arterial compliance, brachial-ankle pulse wave velocity (baPWV), and endothelial function was determined by circulating level of endothelin-1 (ET-1) and nitric oxide metabolite (nitrites/nitrate as metabolite: NOx). Body mass and waist circumference significantly decreased after both intervention programs. Weight loss was greater after dietary modification than after exercise training (-10.1 ± 0.6 kg vs. -3.6 ± 0.5 kg, p < .01). Although arterial stiffness and the plasma levels of ET-1 and NOx were improved after dietary modification or exercise training, there were no differences in those improvements between the 2 types of interventions. Exercise training improves arterial function in obese men without as much weight loss as after dietary modification.

Chemical state information of bulk specimens obtained by SEM-based soft-X-ray emission spectrometry.

Electron-beam-induced soft-X-ray emission spectroscopy (SXES) that uses a grating spectrometer has been introduced to a conventional scanning electron microscope (SEM) for characterizing desired specimen areas of bulk materials. The spectrometer was designed as a grazing incidence flat-field optics by using aberration corrected (varied line spacing) gratings and a multichannel plate detector combined with a charge-coupled device camera, which has already been applied to a transmission electron microscope. The best resolution was confirmed as 0.13 eV at Mg L-emission (50 eV), which is comparable with that of recent dedicated electron energy-loss spectroscopy instruments. This SXES-SEM instrument presents density of states of simple metals of bulk Mg and Li. Apparent band-structure effects have been observed in Si L-emission of Si wafer, P L-emission of GaP wafer, and Al L-emissions of intermetallic compounds of AlCo, AlPd, Al2Pt, and Al2Au.

Physical frailty predicts cognitive decline among community-dwelling older Japanese women: A prospective cohort study from the Otassha study.

BACKGROUND: Physical frailty and cognitive decline are common issues in geriatrics within an aging society, yet the association between them remains controversial. This study aims to evaluate the association between physical frailty and cognitive decline among community-dwelling older Japanese women. METHODS: A prospective cohort study was conducted in an urban area of Tokyo, Japan, involving community-dwelling older adults 65 years or older. Physical frailty was evaluated using the Japanese version of the Cardiovascular Health Study criteria, consisting of five components: shrinking, weakness, exhaustion, slowness, and low activity. Participants were classified as robust, pre-frail, or frail based on the presence of one or more criteria. Cognitive decline was defined as at least a three-point decrease in the Mini-Mental State Examination score from baseline. The association between physical frailty and cognitive decline was examined using binomial logistic regression, adjusting for potential confounders. The analysis yielded multivariable odds ratios (ORs) and 95 % confidence intervals (CIs), with robust participants using as the reference group. RESULTS: A total of 2,122 individuals participated in the baseline survey, with 805 included in the analysis (mean age: 72.9 ± 5.1 years). At baseline, 363 participants were classified as pre-frail, while 32 were classified as frail. During the two-year follow-up period, 68 participants experienced cognitive decline. The multivariable OR (95 % CI) for frailty, using robust as the reference, was 3.50 (1.13, 10.80). Furthermore, a linear relationship was observed between physical frailty and cognitive decline. CONCLUSION: Among older Japanese women, there exists a dose-response relationship between physical frailty status and cognitive decline.

Knee Extensor Muscle Strength Associated with the Onset of Depression in Older Japanese Women: The Otassha Study.

We examined whether knee extensor muscle strength can predict the onset of depressive symptoms in older Japanese women living in Tokyo. A baseline comprehensive geriatric examination was conducted to evaluate isometric knee extensor muscle strength and depressive symptoms (using Geriatric Depression Scale [GDS]) in 2017-2019. A free of neurological disease participants received a series of follow-up examinations following an initial evaluation. A GDS score of ≥5 during follow-up marked the onset of depressive symptoms. A logistic regression model was established after adjustment of baseline GDS score for variables including age, body mass index, smoking, alcohol consumption, comorbidities, working status, hobbies, volunteering, years of education, and dietary variety. Of the 1845 recruited individuals, 1409 were eligible to be targeted for follow-up. Among them, 768 women provided two-year follow-up data and contributed the final analysis. After covariate adjustments, the odds ratios (95% confidence interval) for depressive symptoms were 0.68 (0.39, 1.20) and 0.48 (0.26, 0.91) for the middle and highest tertiles of muscle strength, respectively, using the lowest tertile as reference. A dose-response association between muscle strength and depression (p = 0.022) was identified. This study suggests an inverse dose-response relationship between knee extensor muscle strength and the onset of depressive symptoms in older Japanese women.