High Fragmented Physical Activity as an Early Risk Indicator of Frailty and Mortality in Adults Aged 50 Years and Over.

INTRODUCTION: This study aimed to explore the associations of activity fragmentation with frailty status and all-cause mortality in a representative US sample of people 50 years and over. METHODS: This prospective study used data from the 2003-2006 waves of the National Health and Nutrition Examination Survey (NHANES). Participants 50 years or over were included in the study (n = 2,586). Frailty status was assessed using a valid modification of the Fried criteria. Linked data from the National Death Index registry were used to ascertain mortality. Physical activity fragmentation was measured by accelerometry. To calculate activity fragmentation, an active-to-sedentary transition probability was calculated as the number of physical activity bouts divided by the total sum of minutes spent in physical activity. Age, gender, ethnicity, education, mobility issues, drinking status, smoking status, BMI, and self-reported chronic diseases were reported in the NHANES study. RESULTS: An increment of 1 SD in activity fragmentation was associated with an increased likelihood of frailty (odds ratio [95% confidence interval] = 1.36 [1.13-1.664]). Compared with participants in the high activity fragmentation/low physical activity category, participants in the low activity fragmentation/low physical activity and low activity fragmentation/high physical activity categories were associated with a lower likelihood of frailty. We found a nonlinear association between activity fragmentation and all-cause mortality. Compared with participants in the high activity fragmentation/low physical activity category, participants in the low activity fragmentation/low physical activity, low activity fragmentation/high physical activity, and high activity fragmentation/high physical activity categories were associated with a lower mortality risk. Participants with a low fragmented activity pattern may also overcome some of the detrimental effects associated with sedentary behavior. CONCLUSIONS: Our results suggest that a high fragmented physical activity pattern is associated with frailty and risk of mortality in adults and older adults. This association was independent of total volume of physical activity and time spent sedentary.

Associations between Hospitalization and Device-Assessed Physical Activity in a Representative Sample of Older Adults.

BACKGROUND: Evidence investigating associations between hospitalization and physical activity is scarce and limited to specific populations of older adults. OBJECTIVE: The current study aimed to describe the impact of past hospitalization on current physical activity levels of a large representative sample of European older adults with accelerometry data. METHODS: A representative sample of 856 European older adults aged 50 years and over was included in this study. Hospital admission and utilization (i.e., accumulated times and length of stay in hospital) in the last 12 months were self-reported retrospectively. Physical activity volume (mg) and distribution of intensity (intensity gradient) were assessed with thigh-worn accelerometers. RESULTS: Multivariate linear regressions indicated that hospital admission (15% of the sample) was associated with reduced physical activity volume (-4.29 mg; 95% confidence interval (95% CI), -9.07 to 0.47) of participants. Each additional hospital admission was associated with lower volume (-2.29 mg; 95% CI, -4.65 to 0.06) and poorer distribution of intensity (-0.07; 95% CI, -0.11 to -0.04). Total length of stay was not associated with physical activity. CONCLUSIONS: This study suggests that hospital admission and the number of times admitted, but not accumulated length of stay, may curb physical activity levels of older adults. Public health strategies to promote successful aging should target post-hospitalization physical activity.

Optimal dose and type of physical activity to improve functional capacity and minimise adverse events in acutely hospitalised older adults: a systematic review with dose-response network meta-analysis of randomised controlled trials.

OBJECTIVE: To identify the optimal dose and type of physical activity to improve functional capacity and reduce adverse events in acutely hospitalised older adults. DESIGN: Systematic review and Bayesian model-based network meta-analysis. DATA SOURCES: Four databases were searched from inception to 20 June 2022. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomised controlled trials that assessed the effectiveness of a physical activity-based intervention on at least one functional outcome in people aged ≥50 years hospitalised due to an acute medical condition were included. Pooled effect estimates (ie, standardised mean differences for functional capacity and the ratio of means for adverse events) were calculated using random treatment effects network meta-analysis models. RESULTS: Nineteen studies (3842 participants) met the inclusion criteria. Approximately 100 Metabolic Equivalents of Task per day (METs-min/day) (~40 min/day of light effort or ~25 min/day of moderate effort activities) was the minimal dose to improve the functional capacity of acute hospitalised older adults (standardised mean difference (SMD)=0.28, 95% credible interval (CrI) 0.01 to 0.55). The optimal dose was estimated at 159 METs-min/day (~70 min/day of light effort or ~40 min/day of moderate effort activities; SMD=0.41, 95% CrI 0.08 to 0.72). Ambulation was deemed the most efficient intervention, and the optimal dose was reached at 143 METs-min/day (~50 min/day of slow-paced walking; SMD=0.76, 95% CrI 0.35 to 1.16), showing a high evidential power (87.68%). The minimal effective ambulation dose was estimated at 74 METs-min/day (~25 min/day of slow-paced walking; SMD=0.25, 95% CrI 0.01 to 0.41). Physical activity interventions resulted in a decrease in the rate of adverse events compared with usual care at discharge (ratio of means=0.96, 95% CrI 0.95 to 0.97; median time 7 days). CONCLUSIONS: This meta-analysis yielded low to moderate evidence supporting the use of in-hospital supervised physical activity programmes in acutely hospitalised older adults. As little as ~25 min/day of slow-paced walking is sufficient to improve functional capacity and minimise adverse events in this population. TRIAL REGISTRATION NUMBER: PROSPERO CRD42021271999.

Cardiorespiratory fitness, physical activity, sedentary behavior, and circulating white blood cells in US youth.

The white blood cell (WBC) provides a clue to the presence of illness. Cardiorespiratory fitness (CRF) and physical activity levels are negatively associated with circulating total WBC counts in adults. To date, only a scarce number of studies have investigated these associations among youths. The aim was to elucidate the relationship between CRF and accelerometer-assessed physical activity and sedentary behavior with WBC counts and subfraction concentrations of particular WBC (neutrophils, lymphocytes, monocytes, basophils, and eosinophils) in a large representative national sample of US children and adolescents. Participants accumulating 60 min/day or more of moderate-to-vigorous physical activity (MVPA) were considered active or inactive otherwise. Participants were also categorized into low, average, and high CRF level. The final sample consisted of 1623 children and adolescents (11.9 years old) from 2003 to 2006 cycle and 2624 (14.5 years old) from 1999 to 2004 cycle. CRF was inversely associated with total WBC and segmented neutrophils concentration in both sexes, and MVPA only in boys. Further, active children and adolescents had higher odds of a normal range of WBC count in boys (Odds Ratio [OR] = 1.41 95% CI, 1.02 to 2.34) and girls (OR = 3.52 95% CI, 1.01 to 12.23). In conclusion, our observations indicate that interventions targeting CRF and MVPA could strength the immune system of children and adolescents.

Integrating Sleep, Physical Activity, and Diet Quality to Estimate All-Cause Mortality Risk: A Combined Compositional Clustering and Survival Analysis of the National Health and Nutrition Examination Survey 2005-2006 Cycle.

We aimed to compare all-cause mortality risk across clusters of adults ≥50 years of age (n = 1,035) with common lifestyle behaviors patterns, enrolled in the US National Health and Nutrition Examination Survey (2005-2006). Log-ratio coordinates of 24-hour movement pattern and z scores of diet quality were used as input into a model-based clustering analysis. A Cox regression model was fitted to ascertain the all-cause mortality risk associated with each cluster. Participants were clustered into 4 groups: 1) a group characterized by a better physical activity profile and longer sleep duration coupled with an average diet quality (cluster 1); 2) a group with the poorest activity profile and shortest sleep but also the best diet quality (cluster 2); 3) another group featuring lower levels of activity of either intensity and higher levels of sedentary behavior and also a poor diet quality score (cluster 3); and 4) a group with an average diet quality and the best activity profile in the sample (cluster 4). A combination of a poorer diet and activity profile increased the prospective risk of all-cause mortality. Our findings emphasize the importance of considering the combination of diet quality and 24-hour movement patterns when developing interventions to reduce the risk of premature mortality.

Effects of Whole-Body Vibration on Functional Mobility, Balance, Gait Strength, and Quality of Life in Institutionalized Older People: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The aim of this study was to quantify the effect of whole-body vibration on balance, functional mobility, gait, functional performance, and quality of life in institutionalized older people. Eight databases were systematically reviewed, as recommended by the Cochrane Collaboration. This systematic review was designed to answer the acronym set by the participants, interventions, comparators, and outcomes (PICO)-model. Ten randomized controlled trials were included in the meta-analysis. The analysis of the mean differences (MDs) of the functional mobility assessed with Time Up and Go test was MD = -2.49 s (95% confidence interval, CI, [-4.37, -0.61]; I2 = 68%). In 279 participants from five studies, the overall MD = 0.49 (95% CI [-0.13, 1.11]; I2 = 23%) for gait, and MD = 0.96 (95% CI [-0.45, 2.37]; I2 = 85%) for balance, which represents the total Tinetti score, MD = 1.59 (95% CI [-0.52, 3.70]; I2 = 82%). In summary, whole-body vibration could have benefits on functional mobility in institutionalized older people.

Factors Associated with the Risk of Falls of Nursing Home Residents Aged 80 or Older.

BACKGROUND: Falls are the leading cause of mortality and morbidity in older and represents one of the major and most costly public health problems worldwide. PURPOSE: Evaluate the influences of lower limb muscle performance, static balance, functional independence and quality of life on fall risk as assessed with the timed up and go (TUG) test. DESIGN: Cross-sectional study. METHODS: Fifty-two residents aged 80 or older were assessed and distributed in one of the two study groups (no risk of falls; risk of falls) according to the time to complete the TUG test. A Kistler force platform and linear transducer was used to determinate lower limb muscle performance. Postural Stability (static balance) was measured by recording the center of pressure. The EuroQol-5 dimension was used to assess Health-related quality of life and the Barthel index was used to examine functional status. Student's t-test was performed to evaluate the differences between groups. Correlations between variables were analyzed using Spearman or Pearson coefficient. ROC (receiver operating charasteristic) analysis was used to determine the cut-off points related to a decrease in the risk of a fall. FINDINGS: Participants of no-fall risk group showed better lower limb performance, quality of life, and functional status. Cut-off points were determined for each outcome. CONCLUSIONS: Risk of falls in nursing home residents over the age of 80 is associated with lower limb muscle performance, functional status, and quality of Life. CLINICAL RELEVANCE: Cut-off points can be used by clinicians when working toward fall prevention and could help in determining the optimal lower limb muscle performance level for preventing falls.

Test-retest reliability and minimal detectable change scores for fitness assessment in older adults with type 2 diabetes.

PURPOSE: To assess the intraclass correlation coefficients (ICCs) and to determine the minimal detectable change (MDC95 ) scores of the data for the Hand Grip Strength Test, the Chair Sit and Reach Test (CSRT), the Timed "Up and Go" (TUG) test, the 6-Minute Walk Test (6MWT) and 30 seconds Sit to Stand Test (30s-STS) test in older adults with type 2 NIDDM. DESIGN: Test-retest reliability. METHODS: Eighteen subject participated in two sessions (1 week apart), which included the different tests. FINDINGS: High ICCs (≥ 0.92) were found for all tests. The MDC95 scores were as follows: 4.0 kg for Hand Grip Strength Tests, 7.5 cm for the right leg-CSRT, 9.0 cm for the left leg-CSRT, 1.0 second for the TUG test, 27 m for the 6MWT, and 3.3 repetitions for the 30s-STS test. CONCLUSIONS: All tests evaluated are reliable outcome measures for type 2 NIDDM patients. CLINICAL RELEVANCE: This study has generated novel MCD95 data, which will assist nursing practitioners in both prescribing the most beneficial exercise and interpreting posttreatment changes after rehabilitation in patients with T2DM.

Optimal Dose and Type of Physical Activity to Improve Glycemic Control in People Diagnosed With Type 2 Diabetes: A Systematic Review and Meta-analysis.

BACKGROUND: The optimal dose or type of physical activity to control glycosylated hemoglobin (HbA1c) in people with diabetes remains unknown. Current guidelines do not include consideration of baseline HbA1c for activity prescription. PURPOSE: To examine the dose-response relationship between physical activity and HbA1c (%) in individuals with type 2 diabetes. DATA SOURCES: A systematic search was performed in Embase, MEDLINE, Scopus, CINAHL, SPORTDiscus, and Web of Science. STUDY SELECTION: We included trials that involved participants diagnosed with type 2 diabetes that included any type of physical activity as intervention. DATA EXTRACTION: Pre- and postintervention HbA1c data, population and interventions characteristics, and descriptive statistics were collected to calculate change scores for each study arm. DATA SYNTHESIS: We used Bayesian random-effects meta-analyses to summarize high-quality evidence from 126 studies (6,718 participants). The optimal physical activity dose was 1,100 MET min/week, resulting in HbA1c reductions, ranging from -1.02% to -0.66% in severe uncontrolled diabetes, from -0.64% to -0.49% in uncontrolled diabetes, from -0.47% to -0.40% in controlled diabetes, and from -0.38% to -0.24% in prediabetes. LIMITATIONS: The time required to achieve these HbA1c reductions could not be estimated due to the heterogeneity between interventions' duration and protocols and the interpersonal variability of this outcome. CONCLUSIONS: The result of this meta-analysis provide key information about the optimal weekly dose of physical activity for people with diabetes with consideration of baseline HbA1c level, and the effectiveness of different types of active interventions. These results enable clinicians to prescribe tailored physical activity programs for this population.

A primary care-based randomized controlled trial of 12-week whole-body vibration for balance improvement in type 2 diabetes mellitus.

OBJECTIVE: To determine whether a 12-week whole-body vibration (WBV) training program improved balance in participants with type 2 diabetes mellitus (T2DM). DESIGN: Randomized controlled trial. SETTING: Primary health care setting. PARTICIPANTS: Participants with T2DM (N=50). INTERVENTIONS: Participants were randomly allocated to either a WBV group (n=25), which performed a 12-week WBV-based exercise program on an oscillating platform (12-16Hz-4mm; 3 sessions/wk), or a usual-care control group (n=25). MAIN OUTCOME MEASURES: Clinical and sociodemographic variables were recorded at baseline. Static balance and dynamic balance were also assessed at baseline by measuring postural sway (measurement of center of pressure [COP] excursions in the anteroposterior and mediolateral directions) using a Wii Balance Board and the Timed Up and Go test. RESULTS: Significant between-group differences in COP excursions with participants' eyes closed were found with their feet apart and feet together. In addition, participants in the WBV group exhibited significantly lower COP excursions with their eyes closed after the intervention, while participants in the control group experienced a nonsignificant deterioration in COP excursions (ie, greater excursion) with their eyes open (mediolateral axis). There was no significant difference in the Timed Up and Go test values postintervention. CONCLUSIONS: WBV provides a safe and well-tolerated approach to improve balance in participants with T2DM. These findings may have important implications for falls prevention in those with T2DM in the primary health care setting.

Whole body vibration training improves leg blood flow and adiposity in patients with type 2 diabetes mellitus.

This study aimed at examined the effect of a 12-week whole body vibration (WBV) training program on leg blood flow and body composition in people with type 2 diabetes mellitus (T2DM). Forty participants were randomly assigned to either a WBV training group (WBV; n = 20) or usual-care control group (CON; n = 20). Body composition [waist circumference, waist to hip ratio (WHR), weight, height, percentage of body fat and fat-free mass], heart rate, and blood flow [femoral artery diameter, maximum systolic velocity, maximum diastolic velocity (DV), time averaged mean, pulsatility index and resistance index (RI), mean velocity (V med), and peak blood velocities (PBV)] were assessed at baseline and after 12 weeks. There were significant increases in the blood flow (p = 0.046), V med (p = 0.050), and DV (p = 0.037) after WBV compared with CON. Within-group analysis showed significant differences in V med, PBV, and DV in the WBV group. Significant decreases after the intervention in weight (p < 0.001), waist circumference (p < 0.001), WHR (p < 0.05), and body fat (p < 0.05) were also found, with significant between-groups decreases in all these outcomes in the WBV group. Significant correlations existed between changes in percent body fat and blood flow [blood flow (-0.761), V med (-0.607), PBV (-0.677), and RI (0.0510)]. WBV training can be considered an effective means to increase leg blood flow and to reduce adiposity in patients with T2DM.

Exercise to treat psychopathology and other clinical outcomes in schizophrenia: A systematic review and meta-analysis.

BACKGROUND: Psychopathology and side effects of antipsychotic drugs contribute to worsening physical health and long-term disability, and increasing the risk of mortality in these patients. The efficacy of exercise on these factors is not fully understood, and this lack of knowledge may hamper the routine application of physical activity as part of the clinical care of schizophrenia. AIMS: To determine the effect of exercise on psychopathology and other clinical markers in patients with schizophrenia. We also looked at several moderators. METHOD: MEDLINE, Web of Science, Scopus, CINAHL, SPORTDiscus, PsycINFO, and Cochrane Library databases were systematically searched from inception to October 2022. Randomized controlled trials of exercise interventions in patients 18-65 years old diagnosed with schizophrenia disorder were included. A multilevel random-effects meta-analysis was conducted to pool the data. Heterogeneity at each level of the meta-analysis was estimated via Cochran's Q, I2, and R2. RESULTS: Pooled effect estimates from 28 included studies (1,460 patients) showed that exercise is effective to improve schizophrenia psychopathology (Hedges' g = 0.28, [95% CI 0.14, 0.42]). Exercise presented stronger effects in outpatients than inpatients. We also found exercise is effective to improve muscle strength and self-reported disability. CONCLUSIONS: Our meta-analysis demonstrated that exercise could be an important part in the management and treatment of schizophrenia. Considering the current evidence, aerobic and high-intensity interval training exercises may provide superior benefits over other modalities. However, more studies are warranted to determine the optimal type and dose of exercise to improve clinical outcomes in people with schizophrenia.

Optimal dose and type of exercise to improve cognitive function in older adults: A systematic review and bayesian model-based network meta-analysis of RCTs.

OBJECTIVE: To examine the dose-response relationship between overall and specific types of exercise with cognitive function in older adults. DESIGN: Systematic Review and Bayesian Model-Based Network Meta-Analysis. DATA SOURCES: Systematic search of MEDLINE, Web of Science, Scopus, PsycINFO and SPORTDiscus. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomized controlled trials of exercise interventions in participants aged 50 years or over, and that reported on at least one global cognition outcome. RESULTS: The search returned 1998 records, of which 44 studies (4793 participants; 102 different effect sizes) were included in this review with meta-analysis. There was a non-linear, dose-response association between overall exercise and cognition. We found no minimal threshold for the beneficial effect of exercise on cognition. The estimated minimal exercise dose associated with clinically relevant changes in cognition was 724 METs-min per week, and doses beyond 1200 METs-min per week provided less clear benefits. We also found that the dose-response association was exercise type dependent, and our results show that clinically important effects may occur at lower doses for many types of exercise. Our findings also highlighted the superior effects of resistance exercises over other modalities. CONCLUSIONS: If provided with the most potent modalities, older adults can get clinical meaningful benefits with lower doses than the WHO guidelines. Findings support the WHO recommendations to emphasise resistance training as a critical component of interventions for older adults.

Can Physical Activity Make Up for the Self-Care Disability Effects of Too Much Sitting? A Moderation Analysis in Octogenarians Residing in Living Care Facilities.

BACKGROUND AND PURPOSE: Physical activity can delay the progression of self-care disability in older adults residing in living care facilities. Nonetheless, older adults residing in living care facilities spend most of their time sedentary and do not meet the physical activity recommendation, which may result in increasing self-care disability in this population group. In this study, we aimed to determine whether the association between sedentary time and self-care disability was moderated by moderate-to-vigorous physical activity (MVPA) in older adults residing in living care facilities. METHODS: Sedentary time and MVPA were both measured with accelerometers. Self-care disability was assessed with the Barthel Index. A multivariate regression model was used to ascertain the effects of the interaction between sedentary time and MVPA on the self-care disability of participants. The Johnson-Neyman technique was then used to estimate the exact MVPA threshold at which the effect of sedentary time on self-care disability became nonsignificant. RESULTS: We found a significant effect of sedentary time on self-care disability (standardized ß=-1.66; 95% CI -1.77 to -1.54, P = .013). Results indicated that MVPA moderates the relationship between self-care disability status and sedentary time (standardized ß= 1.14; 95% CI 1.13 to 1.14, P = .032). The Johnson-Neyman technique determined that 51 min/day of MVPA would offset the negative effects of sedentary time on self-care disability. CONCLUSIONS: Our results suggest physical therapists should focus on reducing sedentary time alongside physical activity to prevent the progression to dependency in octogenarians residing in living care facilities.

Replacing Sedentary Behavior With Physical Activity of Different Intensities: Implications for Physical Function, Muscle Function, and Disability in Octogenarians Living in Long-Term Care Facilities.

BACKGROUND: We investigated the associations of replacing sedentary behavior (SB) with physical activity of different intensities on the physical function of octogenarians living in long-term care facilities. METHODS: This pooled study recruited 427 older adults aged 80 years and older (69.1% female; body mass index: 27.53). For 345 participants who provided valid data, we assessed device-measured time spent in SB, light-intensity physical activity (LIPA), and moderate to vigorous physical activity (MVPA). We assessed lower limb physical function, strength, mobility, and disability. We used compositional data analysis to investigate the associations of replacing SB with physical activity on the outcomes. RESULTS: Reallocation of SB to LIPA and MVPA was associated with a higher number of 30-second Chair Stand cycles (LIPA: +0.21, MVPA: +1.81; P < .001), greater peak force (LIPA: +11.96 N, MVPA: +27.68 N; P < .001), peak power (LIPA: +35.82 W, MVPA: +92.73 W; P < .001), peak velocity (LIPA: +0.03 m/s, MVPA: +0.12 m/s; P < .001), higher levels of grip strength (LIPA: +0.68 kg, MVPA: +2.49 kg; P < .001), and less time in the Time Up and Go (LIPA: -7.63 s, MVPA: -12.43 s; P < .001). CONCLUSIONS: Replacing SB with LIPA or MVPA is associated with physical function and disability of older adults living in long-term care facilities.

Impact of Social Isolation on Physical Functioning Among Older Adults: A 9-Year Longitudinal Study of a U.S.-Representative Sample.

INTRODUCTION: Social isolation among older adults is associated with poor health and premature mortality, but its impact on physical functioning is not fully understood. Previous studies have typically relied on community samples, cross-sectional data, and suboptimal prospective designs. This study generates more robust evidence by investigating the longitudinal associations between social isolation and physical functioning in a large panel of older adults. METHODS: Analyses were based on 9 waves of data (2011-2019) from a sample of adults aged ≥65 years from the U.S. National Health and Aging Trends Study (N=12,427 individuals; 54,860 person-year observations) and within-individual fixed-effect panel regression models. Analyses were conducted in 2020. Social isolation was measured using the Social Isolation Index, and physical functioning was measured through the Short Physical Performance Battery. RESULTS: In fully adjusted fixed-effect regression models, each 1-unit increase in the Social Isolation Index resulted in an average decrease of 0.27 units in the Short Physical Performance Battery (95% CI= -0.31, -0.24). This relationship was moderated by age, with the Social Isolation Index bearing a significantly and substantially stronger influence on the Short Physical Performance Battery at older ages than at younger ages. CONCLUSIONS: This study confirms that social isolation is associated with deficits in physical functioning among older adults in the U.S. using more robust data and methods than earlier studies. These findings highlight the importance of incorporating strategies to reduce social isolation in policies aimed at promoting successful aging.

Bidirectional and Dynamic Relationships Between Social Isolation and Physical Functioning Among Older Adults: A Cross-Lagged Panel Model of US National Survey Data.

BACKGROUND: Previous studies examining unidirectional relationships between social isolation and physical functioning among older adults may be biased due to reverse causality. This study leveraged data from a US national sample of older adults and a novel estimation method to identify bidirectional associations between these 2 phenomena and their associated temporal dynamics. METHODS: The analyses were based on 9 waves of panel data from a sample of adults aged 65 and older from the US National Health and Aging Trends Study (n = 12 427 individuals) and a cross-lagged panel model. Social isolation was measured using the Social Isolation Index (SII) and physical functioning through the Short Physical Performance Battery (SPPB). RESULTS: One SD increase in the SPPB was associated with a -0.013 SD decrease (95% confidence interval [CI]: -0.023 to -0.004) in the SII a year later, whereas 1 SD increase in the SII was associated with a larger -0.058 SD decrease (95% CI: -0.069 to -0.046) in the SPPB a year later. The SII→SPPB effect lasted for approximately 5 years, whereas the SPPB→SII lasted for approximately 3 years. CONCLUSIONS: This study confirmed the existence of statistically significant bidirectional associations between social isolation and physical functioning among older adults in the United States, net of reverse causation. Because the effect of social isolation dominates, the findings indicate that public health strategies to promote successful aging should prioritize interventions that enrich older adults' social networks. Furthermore, the effect time horizons yielded by the model point to the optimal timing for the re-delivery of interventions.

Is the Wii balance board a valid and reliable instrument to assess postural stability in older adults with type 2 diabetes mellitus?

AIMS: Evaluate the validity and reliability of the data from the Wii balance board (WBB), against a force platform (FP) in patients with type 2 diabetes mellitus (T2DM). METHODS: Forty-three adults with T2DM (age 62.1 ± 12.1 yrs) in the validity trial and 27 (age 63.5 ± 10.8 yrs) in the reliability study, were tested. Total COP area (mm) and range of antero-posterior (AP) and medio-lateral (ML) COP excursion were collected simultaneously on a FP and a WBB. RESULTS: Mean CoP sway path values were similar in all conditions in the FP when compared with the WBB. Regression model shows that WBB is able to explain most of the variation in CoP sway path data of the FP (between 42 and 72%) for all testing conditions, indicating that the WBB has good concurrent validity. Test-retest reliability for WBB was excellent, except for the COP sway area in the 'eyes open' condition (ICC = 0.55). Both conditions showed modest to excellent reliability in the AP (0.73-0.90) and the ML (0.77-0.91) directions. CONCLUSION: The WBB has been shown to be a valid and reliable method to quantify the COP displacement during different balance tests in older adults with T2DM.

Lifestyle behaviors predict adolescents bullying victimization in low and middle-income countries.

BACKGROUND: In this study we aimed to provide a global perspective of the association between different lifestyle behaviors and bullying in school adolescents and to ascertain whether or not the Human Development Index moderated those associations. METHODS: Data from the Global school-based Student Health Survey were analyzed in 273 121 from 82 countries. Logistic regression was applied to determine country-specific bullying victimization probability from meeting the recommended guidelines for physical activity, excessive sitting time, physical education attendance and active transport. Meta-analysis was then undertaken to ascertain pooled global effect estimates of the relationship between these behaviors and bullying victimization. Linear regression was used to study the relationship between odds of bullying from meeting the lifestyle guidelines and the Human Development Index. RESULTS: Our estimates indicate that excessive sitting time [1.38 (1.34,1.41)], attendance to physical education [0.87 (0.85,0.89)], and active transport [0.94 (0.91,0.97)] but not overall physical activity [1.01 (0.99,1.04)] were associated with bullying in the study sample. LIMITATIONS: The present study is limited by its cross-sectional nature. Also, only two countries were surveyed from the European region CONCLUSIONS: Active commuting and attendance to physical education play a protective role for bullying, while physical activity does not.

Sedentary behaviour is associated with depression symptoms: Compositional data analysis from a representative sample of 3233 US adults and older adults assessed with accelerometers.

BACKGROUND: Evidence supporting the individual associations of sedentary behaviours with depression symptoms commonly ignores the inherent co-dependency between physical activity, sedentary behaviours and sleep in a given 24-hour period. Data analysis based on compositional methods effectively deals with this issue. AIM: To investigate the association between sedentary behaviour and depression symptoms synergistically using compositional analysis methods. METHODS: Participants were a representative sample of 3233 US adults and older adults from the 2005-2006 cycle of the NHANES with valid 24-hour lifestyle behaviours data (i.e., accelerometer-derived physical activity and sedentary behaviour and self-reported sleep) and available self-reported depression symptoms (PHQ-9). The association between sedentary behaviour and depression symptoms scoring was investigated using a compositional zero-inflated Poisson regression analysis. Subsequently, the model estimates were used to evaluate the effects on depression symptoms of replacing time spent in sitting activities with physical activity of different intensities and sleep. LIMITATIONS: The current study is limited by its cross-sectional design. Also, sleep time was self-reported, which could bias our estimations. RESULTS: Increased sedentary behaviour relative to other behaviours was statistically significantly associated with increased depression symptoms (p < 0.001). Reallocating 60 min time from sedentary behaviours to moderate-to-vigorous physical activity (MVPA) and sleep was associated with small reductions in depression symptoms. CONCLUSIONS: A synergistic compositional analysis of accelerometer data uncovered a detrimental association between sedentary behaviour and depression symptoms. These results add to evidence from previous studies. The observed association seems to be principally driven by corresponding reductions in MVPA and sleep duration.