Dose-response associations between physical activity and sedentary time with functional disability in older adults with or without frailty: a prospective cohort study.

Purpose: Evidence regarding the dose-response curve shapes of physical activity (PA) and sedentary time (ST) in older adults with functional disability (FD) is extremely limited. Moreover, these associations may differ depending on with/without frailty. We examined the dose-response associations between moderate-to-vigorous PA (MVPA) and ST with FD among older adults with/without frailty. Methods: We included 7,480 initially nondisabled adults (3,795 men and 3,685 women) aged 65-84 years in Ota City, Tokyo, Japan. MVPA and ST were evaluated using the International Physical Activity Questionnaire-Short Form. FD was prospectively identified using a nationally unified database of the long-term care insurance system. Frailty was determined using Check-List 15, validated against Fried's frailty criteria. Multivariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of MVPA and ST for FD were calculated, and dose-response curves were examined using restricted cubic splines. Results: During 3.6 years of follow-up, 1,001 (13.4%) participants had FD. Among all participants, compared with no MVPA, the HRs for FD reduced linearly up to approximately 2000 metabolic equivalents (METs)■min/week of MVPA, and the lowest HR (HR: 0.61, 95% CI: 0.51-0.74) was reached at around 3,000-4,000 METs■min/week. Although the shape of this association was consistent regardless of with/without frailty, the magnitude of the association tended to be stronger in frail older adults than in non-frail older adults. Compared with those for the median (300 min/day) of ST, the HRs for FD increased linearly as ST reached approximately 600 min/day or more, independent of MVPA, with a maximum HR of 1.31 (95% CI: 1.01-1.71) for 1,080 min/day among all participants. This association was more pronounced among non-frail older adults but not statistically significant among frail older adults. Conclusion: Higher MVPA levels consistently reduced the incidence of FD regardless of frailty in a significant inverse nonlinear dose-response manner. A significant positive nonlinear dose-response association between ST and FD risk was identified among non-frail older adults but not among frail older adults. Increasing MVPA and reducing prolonged ST are important for preventing FD among non-frail older adults. However, reducing ST alone may be insufficient; increasing MVPA, even if by only small increments, is highly recommended for frail older adults.

[A framework for promoting and evaluating "Kayoi-no-ba" initiatives according to the Plan-Do-Check-Action cycle: The ACT-RECIPE framework].

Objective　In 2019, the Ministry of Health, Labour and Welfare emphasized the importance of promoting "Kayoi-no-ba" (or "places to go") initiatives according to the Plan-Do-Check-Action (PDCA) cycle. However, it proposed no specific promotion measures or standardized evaluation frameworks. This study is intended to propose a framework for local government officials to promote and evaluate "Kayoi-no-ba" initiatives according to the PDCA cycle.Methods　The working group (WG) conducted a narrative review of research and extracted evaluation models and indicators that could be used to create the framework. The co-researcher review committee discussed a draft framework prepared by the WG, and the WG revised it based on the discussion; this process was repeated four times. Using the completed framework, we calculated the score of the "Kayoi-no-ba" initiatives in 50 Tokyo municipalities and conducted regional correlation analyses on the relationship between the score of the "Kayoi-no-ba" initiatives in 50 Tokyo municipalities and the number of "Kayoi-no-ba" per 1,000 older persons.Results　The completed framework (named "ACT-RECIPE" by rearranging the underlined characters below) comprised the following six evaluation phases: (1) Comprehension: understanding the key lessons around disability and frailty prevention, and the necessity for "Kayoi-no-ba"; (2) Research and Planning: clarifying the current status of "Kayoi-no-ba," the strengths of the community, and the issues to be addressed through a community assessment, and developing a plan to resolve the issues; (3) Team Building and Collaboration: building a team by collaborating with organizations to solve problems; (4) Implementation: implementing the initiatives necessary to solve problems; (5) Evaluation: verifying changes in output and outcome indicators from the initiatives; and (6) Adjustment and Improvement: re-examining plans, teams, content, and goals based on the evaluation results. In these six phases, we designated 10 core items and accompanying subitems. The median score rate of the ACT-RECIPE framework in 50 municipalities was 75% for "Comprehension," 61% for "Research and Planning," 69% for "Team Building and Collaboration," 64% for "Implementation," 31% for "Evaluation," and 56% for "Adjustment and Improvement," and the mean ACT-RECIPE score rate was 57%. A significant positive correlation (rs=0.43, P=0.002) was observed between the ACT-RECIPE mean score rate and the number of "Kayoi-no-ba" per 1,000 older persons.Conclusion　We proposed the ACT-RECIPE as a framework for promoting and evaluating "Kayoi-no-ba" initiatives according to the PDCA cycle. We hope that this framework will lead to further progress in "Kayoi-no-ba" initiatives and facilitate evaluation of their effectiveness according to the PDCA cycle.

A Community-Based Intervention to Enhance Subjective Well-Being in Older Adults: Study Design and Baseline Participant Profiles.

Promoting subjective well-being is a crucial challenge in aging societies. In 2022, we launched a community-based intervention trial (the Chofu-Digital-Choju Movement). This initiative centered on fostering in-person and online social connections to enhance the subjective well-being of older adults. This paper describes the study design and baseline survey. This quasi-experimental study involved community-dwelling older adults aged 65-84 years in Chofu City, Tokyo, Japan. A self-administered questionnaire was distributed to 3742 residents (1681 men and 2061 women), and a baseline survey was conducted in January 2022. We assessed subjective well-being (primary outcome); psychosocial, physical, and dietary factors; and the use of information and communication technology variables (secondary outcomes) among the participants. After the intervention involving online classes, community hubs, and community events, a 2-year follow-up survey will be conducted to evaluate the effects of the intervention, comparing the intervention group (participants) with the control group (non-participants). We received 2503 questionnaires (66.9% response rate); of these, the analysis included 2343 questionnaires (62.6% valid response rate; mean age, 74.4 (standard deviation, 5.4) years; 43.7% male). The mean subjective well-being score was 7.2 (standard deviation, 1.9). This study will contribute to the development of a prototype subjective well-being strategy for older adults.

Investigating the efficacy of nasal administration for delivering magnetic nanoparticles into the brain for magnetic particle imaging.

This study explored the effectiveness of nasal administration in delivering magnetic nanoparticles into the brain for magnetic particle imaging of target regions. Successful delivery of iron oxide nanoparticles, which serve as contrast agents, to specific sites within the brain is crucial for achieving magnetic particle imaging. Nasal administration has gained attention as a method to bypass the blood-brain barrier and directly deliver therapeutics to the brain. In this study, we investigated surface modification techniques for administering magnetic nanoparticles into the nasal cavity, and provided experimental validation through in vivo studies. By compositing magnetic nanoparticles with gold nanoparticles, we enabled additional surface modification via AuS bonds without compromising their magnetic properties. The migration of the designed PEGylated magnetic nanoparticles into the brain following nasal administration was confirmed by magnetization measurements. Furthermore, we demonstrated the accumulation of these nanoparticles at specific target sites using probe molecules immobilized on the PEG terminus. Thus, the efficacy of delivering magnetic nanoparticles to the brain via nasal administration was demonstrated in this study. The findings of this research are expected to contribute significantly to the realization of magnetic particle imaging of target regions within the brain.

Protective effects of dog ownership against the onset of disabling dementia in older community-dwelling Japanese: A longitudinal study.

This prospective study examined the associations of dog/cat ownership with incident disabling dementia using propensity score matching based on the physical, social, and psychological characteristics of dog and cat owners. We also examined associations of the interaction between dog/cat ownership and exercise habit and social isolation with dementia. Overall, 11,194 older adults selected using stratified and random sampling strategies in 2016 were analyzed. Dog/cat ownership was defined as "current" or "past and never". Disabling dementia was defined according to physicians' rating in the long-term care insurance system in Japan during the approximately 4-year follow-up period. Statistical analysis was weighted by the inverse of the propensity score in the generalized estimating equation after adjusting for follow-up period. Current dog owners (8.6 %) had an odds ratio (OR) of 0.60 (95 %CI: 0.37-0.977) of having disabling dementia compared to past and never owners. For cat ownership, the corresponding OR was 0.98 (95 %CI: 0.62-1.55). Current dog owners with a regular exercise habit had an OR of 0.37 (0.20-0.68) compared to past and never dog owners with no exercise habit. Further, current dog owners with no social isolation had an OR of 0.41 (0.23-0.73) compared to past and never dog owners with social isolation. Dog ownership had a suppressive effect on incident disabling dementia after adjusting for background factors over a 4-year follow-up period. Specifically, dog owners with an exercise habit and no social isolation had a significantly lower risk of disabling dementia.

The relationship between working status in old age and cause-specific disability in Japanese community-dwelling older adults with or without frailty: A 3.6-year prospective study.

AIM: To examine the effects of employment engagement, classified by frailty and working status, on the incidence of disability in urban community-dwelling older adults. METHODS: We used data from 6386 initially nondisabled residents aged 65-84 years from Ota City, Tokyo, Japan, in 2016. The observation duration was 3.6 years. Self-administered questionnaires applied the Cox proportional hazard model by assessing the existence of frailty through Check-List 15 (with a score ≥4 indicating the state of frailty), controlling for age, sex, living situation, education level, equivalent income, chronic conditions, body mass index, instrumental activities of daily living, self-rated health, drinking and smoking status, and social activities. We evaluated the predictive value of working status (full-time, part-time, temporary, or nonworker) at baseline for cause-specific disability (dementia-type vs. non-dementia-type) incidence, identified using the long-term care insurance system's nationally unified database. RESULTS: Of the 6386 participants, 806 (63/1134 full-time workers; 58/1001 part-time workers; 61/547 temporary workers; 624/3704 nonworkers) presented with disabilities during the 3.6-year-long duration. Adjustments for conventional covariates showed that nonfrail full-time and part-time workers, as well as frail full-time workers, had significantly lower risks of all-cause disability incidence. Furthermore, nonfrail and frail full-time workers had significantly lower risks of dementia-type and nondementia-type disabilities, respectively. CONCLUSIONS: The incidence of disability in older adults was influenced by working and frailty status. Engaging in full-time work thus prevents disabilities in older adults, regardless of their frailty status. Meanwhile, nonfrail older adults are able to avoid disabilities even when engaging in part-time work. Geriatr Gerontol Int 2023; 23: 855-863.

Association of dietary variety with the risk for dementia: the Yabu cohort study.

OBJECTIVE: The consumption of various foods is internationally recommended in healthy diet although the association between dietary variety and incident dementia is unknown. We aimed to examine the association between dietary variety and the incidence of disabling dementia in older Japanese adults. DESIGN: We conducted a prospective cohort study. Dietary variety was assessed based on the Dietary Variety Score (DVS). DVS was assessed by counting the number of ten food components (meat, fish/shellfish, eggs, milk, soyabean products, green/yellow vegetables, potatoes, fruit, seaweed and fats/oils) that were consumed almost daily using a FFQ. Participants were categorised into low (0-2 points), middle (3-4 points) and high (5-10 points) groups based on the DVS. Data on newly diagnosed disabling dementia were retrieved from the public long-term care insurance database. Cox proportional hazards regression was used to estimate hazard ratios (HR) with 95 % CI. SETTING: Yabu cohort study, Japan. PARTICIPANTS: A total of 4972 community-dwelling adults aged 65 years or older. RESULTS: During the median follow-up of 6·8 years, 884 participants were newly diagnosed with disabling dementia. After adjusting for confounders, the multivariable-adjusted HR for incident disabling dementia was 0·82 (95 % CI, 0·69, 0·97) for participants in the highest DVS category compared with those in the lowest DVS category (Pfor trend = 0·019). CONCLUSIONS: A higher dietary variety is associated with a reduced risk of disabling dementia in older Japanese adults. These results have potential implications for the development of effective public nutritional approaches to prevent dementia in older adults.

Effects of community-based frailty-preventing intervention on all-cause and cause-specific functional disability in older adults living in rural Japan: A propensity score analysis.

Preventing frailty is crucial in aging societies. We examined the effectiveness of a community-based frailty-prevention program for delaying the onset of functional disability among community-dwelling older adults. From 2014 to 2019, 48 community-based frailty prevention classes (FPC, 60 min/session, once a week), comprising resistance exercise and nutritional or psychosocial programs, were established in Yabu City, Japan. We conducted a baseline survey in 2012 and followed up with participants for up to 6.8 years (4.8 years from establishing the first FPC). We analyzed data from 3350 older people. The primary and secondary outcomes were the onset of functional disability and cause-specific functional disability (including dementia and cardiovascular and orthopedic diseases), respectively. In addition to crude Cox proportional hazard regression, inverse probability of treatment weighting (IPTW) and propensity score matching (PSM; 918 nonparticipants and 459 participants) were used to adjust for confounders. Participants were more likely to be female and have a healthy lifestyle than nonparticipants. During the follow-up, 690 individuals developed a functional disability. The hazard ratio of incident functional disability in the participants was significantly lower than that in nonparticipants in the IPTW (hazard ratio 0.53, 95% confidential interval 0.38-0.75) and PSM (0.52, 0.37-0.71) analyses. In age-stratified analysis, significant associations were observed only in the ≥75-year-old subgroup. In a cause-specific analysis, participation significantly and consistently reduced incident functional disability caused by dementia (IPTW 0.47, 0.25-0.86; PSM 0.45, 0.25-0.83). Community-based FPC may be effective for preventing functional disability, especially caused by dementia, in this population.

Pet ownership-related differences in medical and long-term care costs among community-dwelling older Japanese.

This study examined the differences in medical and long-term care costs over 18 months between pet owners and non-owners among community-dwelling older Japanese. Pet ownership data were collected from 460 community-dwelling adults age 65 years and older. These data were matched with data from the National Health Insurance, health insurance for older people, and Long-Term Care Insurance beneficiaries for 17 months back from the survey on pet ownership. Pet-ownership group-specific trajectories in monthly medical and long-term care costs were modeled by a generalized estimating equation. Among pet owners (n = 96, 20.9%) and non-pet owners (n = 364, 79.1%) there were no significant differences in baseline demographic or health characteristics including chronic disease and self-reported long-term care level. At baseline, pet owners had estimated monthly medical costs of ¥48,054 (SE = 0.11; $418), compared to ¥42,260 (SE = 0.06; $367) for non-pet owners. The monthly medical costs did not differ significantly between the two groups during the 18-month follow-up period. At baseline, estimated monthly long-term care costs of pet owners and non-pet owners were ¥676 (SE = 0.75; $6) and ¥1,420 (SE = 0.52; $12), respectively. During the follow-up period, the non-pet owner to owner ratio of monthly long-term care costs was 1.2 at minimum and 2.3 at maximum. This study showed that monthly long-term care costs for pet owners were approximately half those of non-pet owners. Pet owners might use long-term care services less frequently, or use lighter care services.

Modifiable healthy behaviours and incident disability in older adults: Analysis of combined data from two cohort studies in Japan.

Healthy behaviours reduce the risk of incident disability; however, their components require further consideration. Specifically, little evidence exists on healthy behaviours that comprise modifiable factors, including social aspects, and their effects on those who do not engage in them. This study aimed to examine the association between engaging in healthy behaviours with modifiable factors and incident disability among community-dwelling older adults; as well as identify factors associated with nonengagement in healthy behaviours. We analysed data obtained from 1357 older adults aged 65 years and more without disabilities at baseline. The outcome was incident disability, which was defined based on the long-term care insurance certification in Japan. This study included regular exercise (≥1 day/week), favourable eating habits (≥4 dietary variety score), and social participation (engaging in two or more social activities) as components of healthy behaviours. We used the Cox proportional hazards model to calculate hazard ratios (HR) for incident disabilities. The proportion of those who satisfied all healthy behaviours was 21 %. During the follow-up period (median: 6.3 years), 282 incident disabilities were confirmed. Compared to those who engaged in one healthy behaviour, those who satisfied all healthy behaviours showed a 31 % (95 % confidence interval: 0.48, 0.98) lower HR of incident disability after adjusting for covariates. Current smoking and depressive mood were associated with non-engagement in healthy behaviours. This study found that having physically and socially active lifestyles and favourable eating habits are effective in reducing the risk of incident disability. Meanwhile, several older adults lack the components of a healthy lifestyle. Approaches that focus on multiple healthy behaviours are necessary to enhance the benefits of healthy lifestyles.

Combined Impacts of Physical Activity, Dietary Variety, and Social Interaction on Incident Functional Disability in Older Japanese Adults.

BACKGROUND: This 3.6-year prospective study examined combined impacts of physical activity, dietary variety, and social interaction on incident disability and estimated population-attributable fraction for disability reduction in older adults. METHODS: Participants were 7,822 initially non-disabled residents (3,966 men and 3,856 women) aged 65-84 years of Ota City, Tokyo, Japan. Sufficiency of moderate-to-vigorous-intensity physical activity (MVPA) ≥150 min/week, dietary variety score (DVS) ≥3 (median), and social interaction (face-to-face and/or non-face-to-face) ≥1 time/week was assessed using self-administered questionnaires. Disability incidence was prospectively identified using the long-term care insurance system's nationally unified database. RESULTS: During a follow-up of 3.6 years, 1,046 (13.4%) individuals had disabilities. Independent multivariate-hazard ratios (HRs) and 95% confidence intervals (CIs) of MVPA, DVS, and social interaction sufficiency for incident disability were 0.68 (95% CI, 0.59-0.78), 0.87 (95% CI, 0.77-0.99), and 0.90 (95% CI, 0.79-1.03), respectively. Incident disability HRs gradually reduced with increased frequency of satisfying these behaviors (any one: HR 0.82; 95% CI, 0.65-1.03; any two: HR 0.65; 95% CI, 0.52-0.82; and all three behaviors: HR 0.54; 95% CI, 0.43-0.69), in an inverse dose-response manner (P < 0.001 for trend). Population-attributable fraction for disability reduction in satisfying any one, any two, and all three behaviors were 4.0% (95% CI, -0.2 to 7.9%), 9.6% (95% CI, 4.8-14.1%), and 16.0% (95% CI, 8.7-22.8%), respectively. CONCLUSION: Combining physical activity, dietary variety, and social interaction substantially enhances the impacts on preventing disability among older adults, with evidence of an inverse dose-response manner. Improving insufficient behavior elements through individual habits and preexisting social group activities may be effective in preventing disability in the community.

2-kDa hyaluronan ameliorates human facial wrinkles through increased dermal collagen density related to promotion of collagen remodeling.

BACKGROUND/AIMS: Hyaluronan (HA) oligosaccharides are involved in several biological processes, primarily collagen remodeling and wound healing. Collagen remodeling is retarded in aging skin and causes wrinkles. The aim of this study was to evaluate the effect of 2-kDa HA oligosaccharides (HA2k) on wrinkles by permeation through the stratum corneum and promotion of collagen remodeling. METHODS: A 3D skin model and excised human skin were used to evaluate the permeation of fluorescein-labeled HA2k. The effect of HA2k on collagen metabolism was evaluated by measuring the protein level of type 1 pro-collagen (COL1A1) and matrix metalloproteinase-1 (MMP-1) in the 3D skin model. 0.1% HA2k solution and vehicle control was applied to the human forearm for 8 weeks to evaluate dermal collagen density. To evaluate the effect of HA2k on depth of facial wrinkles, a randomized controlled trial was conducted with 0.1% HA2k lotion and vehicle lotion for 8 weeks. RESULTS: HA2k was confirmed to permeate through the stratum corneum by fluorescent microscopy. Both COL1A1 and MMP-1 were upregulated by HA2k application in a 3D skin model culture. The collagen density was higher for the HA2k-treated forearm than for the vehicle control-treated forearm after 4 weeks. The maximum wrinkle depths in the nasolabial fold and crow's feet area were significantly shallower in the HA2k lotion group than in the control group. CONCLUSION: HA2k permeated the stratum corneum, activated collagen synthesis and degradation simultaneously, and ameliorated wrinkles.

Role of personality traits in determining the association between social participation and mental health: A cross-sectional study in Japan.

The role of personality in determining the association between social participation and mental health was examined by a cross-sectional study. We analyzed data from 4981 older adults aged 65-84 years who were recruited via a mail survey in one region of Japan. We defined poor mental health using a score ≤12 points on the World Health Organization-Five Well-Being Index-Japanese. Personality traits were measured by 10 Item Personality Inventory-Japanese. In women, higher openness positively moderated the association between private group participation (volunteering, sports, hobby, and learning) and mental health, while higher neuroticism negatively moderated it. This study contributes to knowledge about mental health, personality, and participation. The findings provide provisional evidence about recommending private group participation for women with high openness but not those with high neuroticism.

Association between sarcopenia and oral functions in community-dwelling older adults: A cross-sectional study.

BACKGROUND: Few studies have examined the state of oral function in older adults with sarcopenia. We assessed the oral functions of community-dwelling older adults with sarcopenia from multiple perspectives to clarify their potentially low oral function. METHODS: A total of 1517 (86.2%; 990 women, 527 men; mean age 76.1 ± 7.6 years) participants were included in this study. Grip strength, gait speed and skeletal muscle mass index were assessed, and sarcopenia was evaluated according to the criteria of the Asian Working Group for Sarcopenia 2019. The degree of tongue coating, oral moisture, occlusal force, tongue-lip motor function, tongue pressure, masticatory function and swallowing function were assessed. The criteria for oral hypofunction (a disease that is a combination of multiple low oral functions) were used to assess oral function. Statistical analyses were performed using Kolmogorov-Smirnov test, unpaired t-test, Mann-Whitney U test, χ2 test, and univariate and multivariable logistic regression analyses, with each oral function as the dependent variable and sarcopenia as one of the independent variables. The significance level was set at P < 0.05. RESULTS: The prevalence rates of sarcopenia and severe sarcopenia were 14.2% and 3.8%, respectively. The prevalence of oral hypofunction was 39.9%. Compared with the robust group, the sarcopenia and severe sarcopenia groups tended to have a higher frequency of the following components (all P < 0.01): low occlusal force, low tongue-lip motor function, low tongue pressure, low masticatory function, low swallowing function and oral hypofunction. Univariate logistic regression analysis showed that sarcopenia was associated with low occlusal force, low tongue-lip motor function, low tongue pressure, low masticatory function, low swallowing function and oral hypofunction. The odds ratios and 95% confidence intervals of sarcopenia for each oral function were 2.62 [2.00, 3.43], 2.21 [1.69, 2.89], 3.66 [2.79, 4.81], 3.23 [2.46, 4.25], 1.66 [1.26, 2.20] and 3.59 [2.72, 4.72], respectively. Multivariable logistic regression analysis showed that sarcopenia was associated with low occlusal force (1.63 [1.10, 2.40]), low tongue pressure (2.28 [1.65, 3.15]), low masticatory function, (1.94 [1.27, 2.97]), low swallowing function (1.64 [1.17, 2.28]) and oral hypofunction (2.17 [1.52, 3.09]). CONCLUSIONS: This study demonstrated that multiple aspects of oral function were low among community-dwelling older adults with sarcopenia. The potential decline in oral functions in older adults with sarcopenia may have been overlooked until now. This study indicates the need for dental perspectives in intervening with older adults with sarcopenia and the need to encourage them to see dental professionals.

The effect of a multicomponent intervention on occupational fall-related factors in older workers: A pilot randomized controlled trial.

OBJECTIVES: Multicomponent interventions reduce falls among community-dwelling older adults. However, whether this strategy helps reduce occupational falls among older workers is unclear. This pilot trial tested the safety, adherence, and potential effectiveness of a multicomponent intervention for older workers. METHODS: An assessor-blind, parallel-designed randomized controlled trial was conducted in five public employment agencies for seniors in Saitama, Japan. In total, 69 older adults who worked ≥4 days/month were randomly assigned to the intervention (n = 35) or control (n = 34) groups. The intervention group was provided a multicomponent intervention consisting of exercise, nutrition, and psychosocial programs once a week for 8 weeks. Safety was evaluated for all adverse events reported by participants. Adherence was assessed by rates for withdrawal/dropout, exercise practice, and nutritional diary completion. The primary outcome was a change in functional strength related to occupational falls. Secondary outcomes included changes in agility, balance, executive function, visuospatial ability, exercise self-efficiency, dietary variety, social network, and functional capacity. RESULTS: No adverse events were reported by participants. The median withdrawal/dropout, exercise practice, and nutritional diary completion rates were 0%, 80.4%-93.7%, and 100%, respectively. In the adjusted general linear model, the intervention group showed a non-significant but clinically important improvement in functional strength (P value: .081, Cohen's d: 0.57) and significant improvements in agility, balance, and dietary variety compared to the control group. CONCLUSIONS: A multicomponent intervention for older workers would be a safe, acceptable, and effective strategy for improving risk factors for occupational falls.

Dose-Response Associations of Physical Activity and Sitting Time with All-Cause Mortality in Older Japanese Adults.

PURPOSE: Although examining the dose-response curves of physical activity (PA) and sitting time with health-related outcomes is an important research agenda, the results for older Japanese adults are extremely limited. We examined the dose-response associations of PA and sitting time with all-cause mortality among older Japanese. METHODS: Initially, 8,069 non-disabled residents (4,073 men; 3,996 women) aged 65-84 years of Ota City, Japan, were recruited. Moderate-to-vigorous PA (MVPA) and sitting time were evaluated using the International Physical Activity Questionnaire-Short Form. Multivariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of MVPA and sitting time for all-cause mortality were calculated, and the dose-response curves were examined using restricted cubic splines (RCS). RESULTS: During 4.1 years of follow-up, 458 participants (5.7%; 331 men and 127 women) died. Compared with the low MVPA (<600 metabolic equivalents [METs]·minutes/week) group, HR for mortality gradually reduced in moderate (600-3000 METs·minutes/week) and high (>3000 METs·minutes/week) MVPA groups (moderate: HR 0.66; 95% CI, 0.54-0.82; high: HR 0.58; 95% CI, 0.45-0.75; P <0.001 for trend). RCS showed that the HR for mortality reduced linearly up to approximately 2000 METs·minutes/week of MVPA, and maximal risk reduction was seen at approximately 3000-4500 METs·minutes/week of MVPA. No significant dose-response association of sitting time with mortality was observed. CONCLUSIONS: Higher MVPA levels reduced all-cause mortality risk, in a significant inverse non-linear dose-response manner. Sitting time was not significantly associated with all-cause mortality. It is important to disseminate the significance of even a slight increase in the MVPA.

Effect of Polymer Substrate on Adhesion of Electroless Plating in Irradiation-Based Direct Immobilization of Pd Nanoparticles Catalyst.

Pd nanoparticles were directly immobilized on acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), polystyrene (PS), polyphenylene sulfide (PPS), poly(vinyl chloride) (PVC), polypropylene (PP), and polyethylene (PE) polymer substrates via chemical reactions induced by ionizing irradiation. X-ray photoelectron spectroscopy analysis revealed that the chemical state of the immobilized Pd nanoparticles depended on the polymer substrate type. Electroless plating was performed using the immobilized Pd nanoparticles as the catalyst, and Cu-plating films were deposited on all polymer substrates. The results of the tape-peeling test suggested that the chemical state of the immobilized Pd nanoparticles on the polymer substrates affected the plating adhesion strength. Notably, ABS with immobilized Pd particles exhibited a high adhesion strength beyond the practical level, even without prior chemical etching. It was presumed that the high adhesion strength was owing to the anchoring effect of the holes generated on the ABS surface by ionizing irradiation.

Development of Direct Immobilization Technique of Ag Nanoparticles on Resin Substrates Imparting High Antibacterial and Antiviral Activities.

A new method has been developed to impart the antimicrobial activity of silver nanoparticles to resin substrates. A resin substrate immersed in an aqueous solution of silver nitrate was irradiated with gamma ray or high energy electron beams. Silver nanoparticles were successfully immobilized on the resin surface directly by chemical reactions induced by ionizing radiation. It was experimentally confirmed that various resin materials, such as acrylonitrile-butadiene-styrene, polyethylene, polypropylene, polyvinyl chloride, and polycarbonate, were applicable for this process. The effects of gamma ray or electron beam irradiation on resin substrates were almost negligible since the irradiation dose was equal or less than that used for sterilization. Despite the small amount of Ag loadings, the obtained samples showed high antibacterial and antiviral activities.