Short Video Viewing, and Not Sedentary Time, Is Associated with Overweightness/Obesity among Chinese Women.

Previous studies have found that the relationship between sedentary time (ST) and overweightness/obesity is unclear. The association between sedentary behavior and overweightness/obesity may depend on the type of sedentary behavior engaged in. Nowadays, in older Chinese adults, especially females, short video viewing (SVV) is the most popular leisure sedentary behavior. However, the association between SVV and overweightness/obesity remains to be determined. This study aimed to examine the associations between ST and SVV and overweightness/obesity in Chinese community-dwelling older women. A cross-sectional analysis of baseline data from the Physical Activity and Health in Older Women Study was carried out in this study. A total of 1105 older Chinese women aged 60-70 years were included. SVV was estimated using a self-reported questionnaire, and ST was objectively measured using a tri-axial accelerometer. Overweightness/obesity indicators, including body fat ratio (BFR), fat mass (FM), visceral fat mass (VFM), subcutaneous fat mass (SFM), trunk fat mass (TFM), and limb fat mass (LFM), were assessed using multi-frequency bioimpedance analysis. The covariates included socio-demographic data and a range of health-related factors. Multiple linear regression analyses were used to assess the association between ST and SVV and overweightness/obesity. ST was significantly positively associated with all indicators of overweightness/obesity; however, the associations disappeared after adjusting for moderate-to-vigorous-intensity physical activity (MVPA). A higher SVV time was associated with a higher body mass index (BMI) (ß = 0.19, 95% confidence interval (CI): 0.05 to 0.32), BFR (ß = 0.31, 95% CI: 0.07 to 0.56), FM (ß = 0.33, 95% CI: 0.04 to 0.61), VFM (ß = 0.09, 95% CI: 0.01 to 0.16), SFM (ß = 0.24, 95% CI: 0.03 to 0.45), TFM (ß = 0.21, 95% CI: 0.04 to 0.39), and LFM (ß = 0.11, 95% CI: 0.00 to 0.23) in the fully adjusted models. Compared with non-food short videos, short food videos had a greater effect on overweightness/obesity. SVV was an independent risk factor for overweightness/obesity. A reduction in SVV (especially the food category) rather than ST might be an effective way to prevent overweightness/obesity when incorporated in future public health policy formulations.

Nonlinear associations between sleep patterns and sarcopenia risks in older adults.

STUDY OBJECTIVES: Despite considering it as a common geriatric condition, sarcopenia is linked to various behavioral factors that may be changeable. As sleep is one of the important routines in physiological homeostasis, further investigating the underlying relationships of sleep behavior with sarcopenia is urgently needed. We examined the association between sleep parameters (ie, sleep duration, bedtime, wake time, or midsleep time) and sarcopenia risks in older adults, in the total sample and age group subsamples. METHODS: A total of 1,068 older adults in Taiwan were included. Data on bedtime, wake time, and sleep duration were collected through telephone interview. Midsleep time was calculated by the midpoint of bedtime and wake time. Sarcopenia was screened by the SARC-F questionnaire composed of 5 questions (the strength, assistance in walking, rising from a chair, climbing stairs, and falls) as well as higher scores was related to greater risks. Generalized additive models were conducted to examine the nonlinear relationships between sleep parameters and sarcopenia risks. RESULTS: The covariate-adjusted analysis showed that a reverse J-shaped relationship for sleep duration and sarcopenia risk (P < .001) and a significant association for wake time and the SARC-F score (P = .009) in total sample, with considering age-related interaction. No associations were found in the other sleep parameters (bedtime and midsleep time) and sarcopenia in older adults. Similar associations were observed between wake time and the SARC-F score across age groups, while diverse associations of sleep duration with the SARC-F score were found in different age groups. CONCLUSIONS: The sleep pattern is significantly associated with sarcopenia risks in aging adults. Improving inappropriate sleep behaviors in older adults is suggested to prevent a decline in muscle function and promote healthy aging. CITATION: Huang W-C, Lin C-Y, Togo F, et al. Nonlinear associations between sleep patterns and sarcopenia risks in older adults. J Clin Sleep Med. 2022;18(3):731-738.

Potential utility of physical function measures to improve the risk prediction of functional disability in community-dwelling older Japanese adults: a prospective study.

BACKGROUND: While gait speed, one-leg standing balance, and handgrip strength have been shown to be independent predictors for functional disability, it is unclear whether such simple measures of physical function contribute to improved risk prediction of functional disability in older adults. METHODS: A total of 1,591 adults aged ≥ 65 years and without functional disability at baseline were followed up for up to 7.9 years. Functional disability was identified using the database of Japan's Long-term Care Insurance System. Maximum gait speed, one-leg standing time, and handgrip strength were measured at baseline. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) for the association of physical function and functional disability incidence. The incremental predictive value of each physical function measure for risk prediction was quantified using the difference in overall C-statistic, category-free net reclassification improvement (NRI), and integrated discrimination improvement (IDI) index. RESULTS: During follow-up (median: 7.8 years), functional disability was identified in 384 participants. All of the physical function measures were inversely associated with the risk of functional disability, independent of potential confounding factors. The multivariable adjusted HRs (95 % CIs) for functional disability per one standard deviation increment of maximum gait speed, one-leg-standing time, and hand grip strength were 0.73 (0.65-0.83), 0.68 (0.59-0.79), and 0.72 (0.59-0.86), respectively. Incorporation of each of maximum gait speed, one-leg-stand time, and hand grip strength into a basic model with other risk factors significantly improved C-statistic from 0.770 (95 % CIs, 0.751-0.794) to 0.778 (0.759-0.803), 0.782 (0.760-0.805), and 0.775 (0.756-0.800), respectively (all p < 0.05). A model including all three measures had the highest C-statistic of 0.787 (0.765-0.810). The improvements in risk prediction were also confirmed by category-free NRI and IDI index. CONCLUSIONS: Adding any of the three measures to a basic model with other known risk factors significantly improved the prediction of functional disability and addition of all three measures provided further improvement of the prediction in older Japanese adults. These data provide robust evidence to support the practical utility of incorporating these simple physical function measures into functional disability risk prediction tools.

Normative Data of Objectively Measured Physical Activity and Sedentary Time in Community-Dwelling Older Japanese.

BACKGROUND: The amounts of moderate-to-vigorous-intensity physical activity (MVPA), light-intensity physical activity (LPA), and sedentary time (ST) by sex, age, and body mass index (BMI) in older Japanese adults have not been known. We conducted this study to determine the actual physical activity (PA) and ST in this population. SUBJECTS AND METHODS: A total of 3998 community-dwelling Japanese adults aged ≥65 years were investigated. Their levels of PA and ST and number of steps taken daily were assessed for seven consecutive days by a tri-axial accelerometer. Normative values of daily PA and ST were analyzed by age and BMI groups in the men and the women and are presented as mean, median, or decile. RESULTS: The subjects generally adhered to the PA guideline, i.e., ≥10 metabolic equivalents (METs)·hour MVPA per week. Older age was associated with lower adherence to the PA guideline. CONCLUSIONS: Normative values (mean, median, or decile) were yielded for MVPA, LPA, and ST based on accelerometer readings in a large sample of older community-dwelling Japanese adults. One-half of the subjects' waking time was spent being sedentary, and >70% of the subjects met the current PA guideline by engaging in MVPA.

Nonwearable Sensor-Based In-Home Assessment of Subtle Daily Behavioral Changes as a Candidate Biomarker for Mild Cognitive Impairment.

Patients show subtle changes in daily behavioral patterns, revealed by traditional assessments (e.g., performance- or questionnaire-based assessments) even in the early stage of Alzheimer's disease (AD; i.e., the mild cognitive impairment (MCI) stage). An increase in studies on the assessment of daily behavioral changes in patients with MCI and AD using digital technologies (e.g., wearable and nonwearable sensor-based assessment) has been noted in recent years. In addition, more objective, quantitative, and realistic evidence of altered daily behavioral patterns in patients with MCI and AD has been provided by digital technologies rather than traditional assessments. Therefore, this study hypothesized that the assessment of daily behavioral changes with digital technologies can replace or assist traditional assessment methods for early MCI and AD detection. In this review, we focused on research using nonwearable sensor-based in-home assessment. Previous studies on the assessment of behavioral changes in MCI and AD using traditional performance- or questionnaire-based assessments are first described. Next, an overview of previous studies on the assessment of behavioral changes in MCI and AD using nonwearable sensor-based in-home assessment is provided. Finally, the usefulness and problems of nonwearable sensor-based in-home assessment for early MCI and AD detection are discussed. In conclusion, this review stresses that subtle changes in daily behavioral patterns detected by nonwearable sensor-based in-home assessment can be early MCI and AD biomarkers.

Estimating prevalence of subjective cognitive decline in and across international cohort studies of aging: a COSMIC study.

BACKGROUND: Subjective cognitive decline (SCD) is recognized as a risk stage for Alzheimer's disease (AD) and other dementias, but its prevalence is not well known. We aimed to use uniform criteria to better estimate SCD prevalence across international cohorts. METHODS: We combined individual participant data for 16 cohorts from 15 countries (members of the COSMIC consortium) and used qualitative and quantitative (Item Response Theory/IRT) harmonization techniques to estimate SCD prevalence. RESULTS: The sample comprised 39,387 cognitively unimpaired individuals above age 60. The prevalence of SCD across studies was around one quarter with both qualitative harmonization/QH (23.8%, 95%CI = 23.3-24.4%) and IRT (25.6%, 95%CI = 25.1-26.1%); however, prevalence estimates varied largely between studies (QH 6.1%, 95%CI = 5.1-7.0%, to 52.7%, 95%CI = 47.4-58.0%; IRT: 7.8%, 95%CI = 6.8-8.9%, to 52.7%, 95%CI = 47.4-58.0%). Across studies, SCD prevalence was higher in men than women, in lower levels of education, in Asian and Black African people compared to White people, in lower- and middle-income countries compared to high-income countries, and in studies conducted in later decades. CONCLUSIONS: SCD is frequent in old age. Having a quarter of older individuals with SCD warrants further investigation of its significance, as a risk stage for AD and other dementias, and of ways to help individuals with SCD who seek medical advice. Moreover, a standardized instrument to measure SCD is needed to overcome the measurement variability currently dominant in the field.

Study design and baseline characteristics of a population-based prospective cohort study of dementia in Japan: the Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD).

BACKGROUND: The burden of dementia is growing rapidly and has become a medical and social problem in Japan. Prospective cohort studies have been considered an effective methodology to clarify the risk factors and the etiology of dementia. We aimed to perform a large-scale dementia cohort study to elucidate environmental and genetic risk factors for dementia, as well as their interaction. METHODS: The Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD) is a multisite, population-based prospective cohort study of dementia, which was designed to enroll approximately 10,000 community-dwelling residents aged 65 years or older from 8 sites in Japan and to follow them up prospectively for at least 5 years. Baseline exposure data, including lifestyles, medical information, diets, physical activities, blood pressure, cognitive function, blood test, brain magnetic resonance imaging (MRI), and DNA samples, were collected with a pre-specified protocol and standardized measurement methods. The primary outcome was the development of dementia and its subtypes. The diagnosis of dementia was adjudicated by an endpoint adjudication committee using standard criteria and clinical information according to the Diagnostic and Statistical Manual of Mental Disorders, 3rd Revised Edition. For brain MRI, three-dimensional acquisition of T1-weighted images was performed. Individual participant data were pooled for data analyses. RESULTS: The baseline survey was conducted from 2016 to 2018. The follow-up surveys are ongoing. A total of 11,410 individuals aged 65 years or older participated in the study. The mean age was 74.4 years, and 41.9% were male. The prevalence of dementia at baseline was 8.5% in overall participants. However, it was 16.4% among three sites where additional home visit and/or nursing home visit surveys were performed. Approximately two-thirds of dementia cases at baseline were Alzheimer's disease. CONCLUSIONS: The prospective cohort data from the JPSC-AD will provide valuable insights regarding the risk factors and etiology of dementia as well as for the development of predictive models and diagnostic markers for the future onset of dementia. The findings of this study will improve our understanding of dementia and provide helpful information to establish effective preventive strategies for dementia in Japan.

Education and the moderating roles of age, sex, ethnicity and apolipoprotein epsilon 4 on the risk of cognitive impairment.

BACKGROUND: We examined how the relationship between education and latelife cognitive impairment (defined as a Mini Mental State Examination score below 24) is influenced by age, sex, ethnicity, and Apolipoprotein E epsilon 4 (APOE*4). METHODS: Participants were 30,785 dementia-free individuals aged 55-103 years, from 18 longitudinal cohort studies, with an average follow-up ranging between 2 and 10 years. Pooled hazard ratios were obtained from multilevel parametric survival analyses predicting cognitive impairment (CI) from education and its interactions with baseline age, sex, APOE*4 and ethnicity. In separate models, education was treated as continuous (years) and categorical, with participants assigned to one of four education completion levels: Incomplete Elementary; Elementary; Middle; and High School. RESULTS: Compared to Elementary, Middle (HR = 0.645, P = 0.004) and High School (HR = 0.472, P < 0.001) education were related to reduced CI risk. The decreased risk of CI associated with Middle education weakened with older baseline age (HR = 1.029, P = 0.056) and was stronger in women than men (HR = 1.309, P = 0.001). The association between High School and lowered CI risk, however, was not moderated by sex or baseline age, but was stronger in Asians than Whites (HR = 1.047, P = 0.044), and significant among Asian (HR = 0.34, P < 0.001) and Black (HR = 0.382, P = 0.016), but not White, APOE*4 carriers. CONCLUSION: High School completion may reduce risk of CI associated with advancing age and APOE*4. The observed ethnoregional differences in this effect are potentially due to variations in social, economic, and political outcomes associated with educational attainment, in combination with neurobiological and genetic differences, and warrant further study.

Associations of Objectively Measured Patterns of Sedentary Behavior and Physical Activity with Frailty Status Screened by The Frail Scale in Japanese Community-Dwelling Older Adults.

The objective of this study was to investigate the association between objectively measured patterns of sedentary behavior (SB) and physical activity (PA) and frailty status in Japanese community-dwelling older adults. Data was from 65-75 years older adults from the baseline of Itoshima Frail Study were used. Frailty was assessed using a Japanese version of the FRAIL scale. SB and PA were measured using an accelerometer. Multinomial logistic regression and receiver operating characteristic curve analyses were used to investigate the associations of SB and PA patterns with frailty status. Of the total 819 older adults, half were female (51.8%). The prevalence of robust, pre-frailty and frailty was 60.2%, 27.8%, and 12.0%, respectively. SB variables including total sedentary time, sedentary time in bouts of ≥ 10 min and ≥ 30 min, and mean sedentary bout duration were not associated with frailty status. Except LPA and moderate-to-vigorous physical activity (MVPA) in bouts of < 10 min, PA variables including total MVPA time, MVPA in bouts of ≥ 10 min (bouted MVPA), and steps were significantly associated with lower prevalence of frailty. Area under the curves (AUCs) of total MVPA time, bouted MVPA, and steps were 0.64 (P < 0.001), 0.67 (P < 0.001), and 0.66 (P < 0.001), respectively. The optimal cut-off value of total MVPA time, bouted MVPA, and steps to discriminate between frailty and non-frailty were 43.25 min/day, 9.13 min/day, and 3841 steps/day, respectively. Higher levels of total MVPA time, bouted MVPA, and daily steps were negatively associated with frailty. Lower amounts of bouted MVPA (70 min/week) or steps (4000 steps/day) may be achievable initial targets in older adults for frailty management.

Dose-Response Association Between Accelerometer-Assessed Physical Activity and Incidence of Functional Disability in Older Japanese Adults: A 6-Year Prospective Study.

BACKGROUND: It is unknown whether moderate-to-vigorous physical activity (MVPA) in bouts of <10 minutes protects against disability risks or if only 10 minutes bouts of MVPA is critical. Additionally, it is unclear whether light physical activity (LPA) or its accumulation patterns is associated with functional disability. METHODS: A total of 1,687 adults aged ≥65 years and without functional disability at baseline were followed up for 6 years. Functional disability was identified using the database of Japan's Long-term Care Insurance System. Physical activity was measured using a tri-axial accelerometer secured to the waist. RESULTS: Functional disability was identified in 274 participants (16.2%). When examined as quartiles, higher levels of all MVPA measures were dose-dependently associated with lower risk of functional disability. Associations of MVPA in ≥10 and <10 minutes bouts remained significant in a mutually adjusted model. Neither total LPA nor LPA in bout of ≥10 minutes, but LPA in bouts of <10 minutes was associated with functional disability. Analyses using restricted cubic spline functions showed that associations of all MVPA measures and LPA in bouts of <10 minutes with functional disability were linear (p for nonlinear >.05). The hazard ratios (HRs; 95% confidence interval [CI]) for functional disability per 10 minutes increment of total MVPA and LPA in bout of <10 minutes were 0.86 (0.81-0.92) and 0.96 (0.93-0.99), respectively. CONCLUSIONS: Higher MVPA, regardless accumulation patterns, or LPA in bouts of <10 minutes was associated with lower risk of functional disability in a linear dose-response manner in older adults.

Different patterns in age-related morphometric alteration of myelinated fibers and capillaries of the tibial nerve: a longitudinal study in normal rats.

Age-related regression of myelinated fibers in peripheral nerves of the lower limbs is strongly influenced by capillaries and results in balance dysfunction and falls. However, the temporal relationships between alteration patterns of myelinated fibers and capillaries have not yet been clarified. This study aimed to investigate age-related morphological and histological changes of both myelinated fibers and capillaries in peripheral nerves to clarify whether myelinated fibers or capillaries change earlier. Seven male Wistar rats each were randomly selected at 20 weeks (young group), 70 weeks (middle group), and 97 weeks (old group) for histological evaluations. The left and right tibial nerves were removed morphologically and histologically to examine myelinated fibers and capillaries. Axon diameter and myelin thickness were almost unaltered in the middle group compared with the young group but were significantly reduced in the old group when compared with the other two groups. However, the capillary diameter and number of microvascular branch points were substantially reduced in the middle group. The current study demonstrates that myelinated fibers of peripheral nerves show signs of regression in elderly rats, whereas capillaries start to reduce in middle-aged animals. In normal aging of the tibial nerve, capillaries may regress before myelinated fibers.

The Association of Sedentary Behaviour and Cognitive Function in People Without Dementia: A Coordinated Analysis Across Five Cohort Studies from COSMIC.

BACKGROUND: Besides physical activity as a target for dementia prevention, sedentary behaviour is hypothesized to be a potential target in its own right. The rising number of persons with dementia and lack of any effective treatment highlight the urgency to better understand these modifiable risk factors. Therefore, we aimed to investigate whether higher levels of sedentary behaviour are associated with reduced global cognitive functioning and slower cognitive decline in older persons without dementia. METHODS: We used five population cohorts from Greece, Australia, USA, Japan, and Singapore (HELIAD, PATH, SALSA, SGS, and SLAS2) from the Cohort Studies of Memory in an International Consortium. In a coordinated analysis, we assessed the relationship between sedentary behaviour and global cognitive function with the use of linear mixed growth model analysis (mean follow-up range of 2.0-8.1 years). RESULTS: Baseline datasets combined 10,450 older adults without dementia with a mean age range between cohorts of 66.7-75.1 years. After adjusting for multiple covariates, no cross-sectional association between sedentary behaviour and cognition was found in four studies. One association was detected where more sedentary behaviour was cross-sectionally linked to higher cognition levels (SLAS2, B = 0.118 (0.075; 0.160), P < 0.001). Longitudinally, there were no associations between baseline sedentary behaviour and cognitive decline (P > 0.05). CONCLUSIONS: Overall, these results do not suggest an association between total sedentary time and lower global cognition in older persons without dementia at baseline or over time. We hypothesize that specific types of sedentary behaviour may differentially influence cognition which should be investigated further. For now, it is, however, too early to establish undifferentiated sedentary time as a potential effective target for minimizing cognitive decline in older adults without dementia.

Development of a Fried Frailty Phenotype Questionnaire for Use in Screening Community-Dwelling Older Adults.

OBJECTIVES: The aim of this study was to develop a Fried Frailty Phenotype Questionnaire (FFPQ) and a Japanese FRAIL (fatigue, resistance, ambulation, illnesses, and loss of weight) scale (FRAIL-J) and to evaluate the reliability and validity of both questionnaires in Japanese community-dwelling older adults. DESIGN: Cross-sectional analysis of Itoshima Frail Study (IFS). SETTING: The IFS is an ongoing community-based prospective study in Itoshima (Japan). PARTICIPANTS: A total of 858 older adults age 65-75 years. METHODS: The FRAIL-J comprises 5 existing items comparable to those in original FRAIL scale but with broader utilization in the Japanese healthcare system. In FFPQ, resistance, ambulation, and loss of weight were the same as those in FRAIL-J. Fatigue was the same with exhaustion in FFP and inactivity was assessed using a yes or no question. Data including demographics, and physical and cognitive functions, and objective physical activity was collected and analyzed in relation to both questionnaires. RESULTS: The FFPQ and FRAIL-J showed low internal consistency (Kuder-Richardson formula 20 coefficients = 0.32 and 0.29) and good test-retest reliability (intraclass correlation coefficients = 0.79 and 0.72). The correlations ranged from -0.22 to 0.49 when correlating each item with cross-sectional outcomes. Using FFP as a criterion, the ares under the curve for FRAIL-J and FFPQ were 0.86 and 0.88, respectively. The optimal cut-off for FRAIL-J was 2, with a higher Youden index (66.7% vs 20.3% for 3) and a high negative predictive value (99.5%) but low positive predictive value (13.1%). As for FFPQ, either 2 or 3 was evaluated as cut-off because the Youden index (62.2% vs 58.5%) and negative predictive value (99.7% vs 99.2%) were similar although the positive predictive value was low (9.7% vs 33.3%). Using a 2-point cut-off, both questionnaires had slight agreement with FFP. The highest agreement (kappa = 0.42) was found between FFP and FFPQ using a 3-point cut-off. CONCLUSIONS/IMPLICATIONS: The FFPQ and FRAIL-J can be used for frailty screening in Japanese community-dwelling older adults.

Validity of estimating physical activity intensity using a triaxial accelerometer in healthy adults and older adults.

BACKGROUND: A triaxial accelerometer with an algorithm that could discriminate locomotive and non-locomotive activities in adults has been developed. However, in the elderly, this accelerometer has not yet been validated. The aim were to examine the validity of this accelerometer in the healthy elderly, and to compare the results with those derived in a healthy younger sample. METHODS: Twenty-nine healthy elderly subjects aged 60-80 years (Elderly), and 42 adults aged 20-59 years (Younger) participated. All subjects performed 11 activities, including locomotive and non-locomotive activities with a Douglas bag while wearing the accelerometer (Active style Pro HJA-750C). Physical activity intensities were expressed as metabolic equivalents (METs). The relationship between the METs measured using the Douglas bag and METs predicted using the accelerometer was evaluated. RESULTS: A significant correlation between actual and predicted METs was observed in both Elderly (r=0.85, p<0.001) and Younger (r=0.88, p<0.001). Predicted METs significantly underestimated compared with actual METs in both groups (p<0.001). The mean of the errors was -0.6±0.6 METs in Elderly and -0.1±0.5 METs in Younger. The degree of underestimation increased with increasing METs in Elderly (p<0.001). A stepwise multiple regression analysis revealed that predicted METs, age, and weight were related to actual METs in both groups. CONCLUSION: The degree of correlation between predicted and actual METs was comparable in elderly and younger participants, but the prediction errors were greater in elderly participants, particular at higher-intensity activities, which suggests that different predicting equations may be needed for the elderly.

Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study.

BACKGROUND: With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups. METHODS AND FINDINGS: We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54-105 (mean = 72.7) years and without dementia at baseline. Studies had 2-15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = -0.1, SE = 0.01), APOE*4 carriage (B = -0.31, SE = 0.11), depression (B = -0.11, SE = 0.06), diabetes (B = -0.23, SE = 0.10), current smoking (B = -0.20, SE = 0.08), and history of stroke (B = -0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = -0.07, SE = 0.01), APOE*4 carriage (B = -0.41, SE = 0.18), and diabetes (B = -0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = -0.24, SE = 0.12), and between diabetes and cognitive decline (B = -0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife. CONCLUSIONS: These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences.

Longitudinal Changes of Physical Activity and Sedentary Time in the Middle-Aged and Older Japanese Population: The Hisayama Study.

BACKGROUND: The purpose of this study was to describe changes in physical activity volumes and sedentary time over 3 years in the middle-aged and older Japanese population. METHODS: Study participants included 1151 Japanese community-dwelling residents aged ≥40 years in 2009 who underwent 2 sets of health examinations (2009 and 2012). Using a triaxial accelerometer, longitudinal changes in sedentary time, light physical activity volume, moderate to vigorous physical activity volume, number of steps, and total physical activity volume were evaluated according to sex, age (40-49, 50-59, 60-69, 70-79, and ≥80 y), and obese (nonobese and obese) categories. RESULTS: Sedentary time significantly increased, and all physical activity volumes significantly decreased among all participants. Although most variables did not change significantly in the 40-49 and 50-59 year age categories, similar changes as all participants were observed across all other categories. In the correlation analyses, changes in sedentary time correlated, at most, only modestly for each change in physical activity volumes, indicating that increased physical activity volume does not always lead to decreased sedentary time, and vice versa. CONCLUSIONS: Strategies to reduce sedentary time and promote physical activity are needed in Japan, particularly for people aged ≥60 years.

Objectively measured sedentary time and diabetes mellitus in a general Japanese population: The Hisayama Study.

AIMS/INTRODUCTION: The present study aimed to examine cross-sectional associations between objectively measured sedentary time and the prevalence of diabetes mellitus in a general Japanese population, and to elucidate possible mediating roles of diet, obesity and insulin resistance in this relationship. MATERIALS AND METHODS: A total of 1,758 community-dwelling individuals aged 40-79 years wore an accelerometer for ≥7 days and underwent a comprehensive health examination in 2012. Diabetes mellitus was diagnosed by a 75-g oral glucose tolerance test. The associations of sedentary time with the presence of diabetes mellitus and the levels of the homeostasis model assessment of insulin resistance were estimated by logistic and linear regression models. RESULTS: After adjustment for demographic and lifestyle factors including moderate-to-vigorous physical activity, participants who spent ≥10 h in sedentary time had a significantly higher odds ratio of the presence of diabetes than those who spent <6 h in sedentary time (odds ratio 1.84, 95% confidence interval 1.02-3.31). This significant association remained after adjusting for overall and central obesity (as measured by body mass index and waist circumference), but weakened after adjusting for dietary energy intake or homeostasis model assessment of insulin resistance. Sedentary time was positively associated with homeostasis model assessment of insulin resistance levels among non-diabetic participants after adjusted for obesity or energy intake (P for trend <0.01). CONCLUSIONS: Longer sedentary time was associated with a higher prevalence of diabetes mellitus in a general Japanese population. Insulin resistance appeared to be mainly involved in this association. These results highlight the importance of public health strategies targeting reductions in sedentary time for the primary prevention of diabetes mellitus.

Remodeling of myelinated fibers and internal capillaries in distal peripheral nerves following aerobic exercise in aged rats.

The aim of this study was to determine whether aerobic exercise (AE) in old age contributes to improving the morphologies of myelinated fibers (MFs) in peripheral nerves as well as capillaries. Furthermore, we investigated whether such processes are associated with complementary activity of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the circulating blood and peripheral nerve tissue. Fourteen male Wistar rats (age: 95 wk) were randomly divided into moderate AE ( n = 8) and sedentary (SED; n = 6) groups. Rats in the AE group performed treadmill running for 1 h per day for 2 wk, following which the bilateral tibial nerves of the two groups were removed to examine MF and capillary structure. Levels of BDNF and VEGF in the serum and peripheral nerves were analyzed via enzyme-linked immunosorbent assay. Myelin thickness, axon diameter, and capillary luminal diameter were significantly larger in the AE group than in the SED group ( P < 0.0001). Levels of serum BDNF and VEGF were significantly lower and higher, respectively, in the AE group than in the SED group ( P < 0.001). Conversely, BDNF and VEGF levels in tibial nerve tissue were significantly higher, respectively, and lower in the AE group than in the SED group ( P < 0.001). In conclusion, our study indicates that regular AE induces enlargement of the capillaries and thickens the myelin in aged peripheral nerves, likely via a complementary process involving BDNF and VEGF. NEW & NOTEWORTHY Accumulating evidence indicates that age-related sarcopenia is accompanied by the degeneration of myelinated fibers (MFs) in peripheral nerves. Our study indicates that regular aerobic exercise contributes to increased thickness of the myelin surrounding MFs and enlargement of the capillaries, likely via a complementary process involving brain-derived neurotrophic factor and vascular endothelial growth factor. Our findings demonstrate that regular, moderate-intensity aerobic exercise may help to prevent and reverse peripheral nerve regression in older adults.

Long-Term Exercise Protects against Cellular Stresses in Aged Mice.

The current study examined the effect of aging and long-term wheel-running on the expression of heat shock protein (HSP), redox regulation, and endoplasmic reticulum (ER) stress markers in tibialis anterior (T.A.) and soleus muscle of mice. Male mice were divided into young (Y, 3-month-old), old-sedentary (OS, 24-month-old), and old-exercise (OE, 24-month-old) groups. The OE group started voluntary wheel-running at 3 months and continued until 24 months of age. Aging was associated with a higher thioredoxin-interacting protein (TxNiP) level, lower thioredoxin-1 (TRX-1) to TxNiP ratio-a determinant of redox regulation and increased CHOP, an indicator of ER stress-related apoptosis signaling in both muscles. Notably, GRP78, a key indicator of ER stress, was selectively elevated in T.A. Long-term exercise decreased TxNiP in T.A. and soleus muscles and increased the TRX-1/TxNiP ratio in soleus muscle of aged mice. Inducible HSP70 and constituent HSC70 were upregulated, whereas CHOP was reduced after exercise in soleus muscle. Thus, our data demonstrated that aging induced oxidative stress and activated ER stress-related apoptosis signaling in skeletal muscle, whereas long-term wheel-running improved redox regulation, ER stress adaptation and attenuated ER stress-related apoptosis signaling. These findings suggest that life-long exercise can protect against age-related cellular stress.