Bidirectional associations of accelerometer-derived physical activity and stationary behavior with self-reported mental and physical health during midlife.

BACKGROUND: Moderate-to-vigorous intensity physical activity (MVPA) is associated with favorable self-rated mental and physical health. Conversely, poor self-rated health in these domains could precede unfavorable shifts in activity. We evaluated bidirectional associations of accelerometer-estimated time spent in stationary behavior (SB), light intensity physical activity (LPA), and MVPA with self-rated health over 10 years in in the CARDIA longitudinal cohort study. METHODS: Participants (n = 894, age: 45.1 ± 3.5; 63% female; 38% black) with valid accelerometry wear and self-rated health at baseline (2005-6) and 10-year follow-up (2015-6) were included. Accelerometry data were harmonized between exams and measured mean total activity and duration (min/day) in SB, LPA, and MVPA; duration (min/day) in long-bout and short-bout SB (≥30 min vs. < 30 min) and MVPA (≥10 min vs. < 10 min) were also quantified. The Short-Form 12 Questionnaire measured both a mental component score (MCS) and physical component score (PCS) of self-rated health (points). Multivariable linear regression associated baseline accelerometry variables with 10-year changes in MCS and PCS. Similar models associated baseline MCS and PCS with 10-year changes in accelerometry measures. RESULTS: Over 10-years, average (SD) MCS increased 1.05 (9.07) points, PCS decreased by 1.54 (7.30) points, and activity shifted toward greater SB and less mean total activity, LPA, and MVPA (all p < 0.001). Only baseline short-bout MVPA was associated with greater 10-year increases in MCS (+ 0.92 points, p = 0.021), while baseline mean total activity, MVPA, and long-bout MVPA were associated with greater 10-year changes in PCS (+ 0.53 to + 1.47 points, all p < 0.005). In the reverse direction, higher baseline MCS and PCS were associated with favorable 10-year changes in mean total activity (+ 9.75 cpm, p = 0.040, and + 15.66 cpm, p < 0.001, respectively) and other accelerometry measures; for example, higher baseline MCS was associated with - 13.57 min/day of long-bout SB (p < 0.001) and higher baseline PCS was associated with + 2.83 min/day of MVPA (p < 0.001) in fully adjusted models. CONCLUSIONS: The presence of bidirectional associations between SB and activity with self-rated health suggests that individuals with low overall activity levels and poor self-rated health are at high risk for further declines and supports intervention programming that aims to dually increase activity levels and improve self-rated health.

Accuracy and Acceptability of Commercial-Grade Physical Activity Monitors in Older Adults.

The aim of this study was to evaluate accuracy of seven commercial activity monitors in measuring steps in older adults with varying walking abilities and to assess monitor acceptability and usability. Forty-three participants (age = 87 ± 5.7 years) completed a gait speed assessment, two walking trials while wearing the activity monitors, and questionnaires about usability features and activity monitor preferences. The Accusplit AX2710 Accelerometer Pedometer had the highest accuracy (93.68% ± 13.95%), whereas the Fitbit Charge had the lowest (39.12% ± 40.3%). Device accuracy varied based on assistive device use, and none of the monitors were accurate at gait speeds <0.08 m/s. Barriers to monitor usability included inability to apply monitor and access the step display. Monitor accuracy was rated as the most important feature, and ability to interface with a smart device was the least important feature. This study identified the limitations of the current commercial activity monitors in both step counting accuracy and usability features for older adults.

Reducing sedentary behaviour to decrease chronic low back pain: the stand back randomised trial.

OBJECTIVE: The Stand Back study evaluated the feasibility and effects of a multicomponent intervention targeting reduced prolonged sitting and pain self-management in desk workers with chronic low back pain (LBP). METHODS: This randomised controlled trial recruited 27 individuals with chronic LBP, Oswestry Disability Index (ODI) >10% and desk jobs (sitting ≥20 hours/week). Participants were randomised within strata of ODI (>10%-<20%, ≥20%) to receive bimonthly behavioural counselling (in-person and telephone), a sit-stand desk attachment, a wrist-worn activity-prompting device and cognitive behavioural therapy for LBP self-management or control. Self-reported work sitting time, visual analogue scales (VAS) for LBP and the ODI were assessed by monthly, online questionnaires and compared across intervention groups using linear mixed models. RESULTS: Baseline mean (SD) age was 52 (11) years, 78% were women, and ODI was 24.1 (10.5)%. Across the 6-month follow-up in models adjusted for baseline value, work sitting time was 1.5 hour/day (P<0.001) lower comparing intervention to controls. Also across follow-up, ODI was on average 8 points lower in intervention versus control (P=0.001). At 6 months, the relative decrease in ODI from baseline was 50% in intervention and 14% in control (P=0.042). LBP from VAS was not significantly reduced in intervention versus control, though small-to-moderate effect sizes favouring the intervention were observed (Cohen's d ranged from 0.22 to 0.42). CONCLUSION: An intervention coupling behavioural counselling targeting reduced sedentary behaviour and pain self-management is a translatable treatment strategy that shows promise for treating chronic LBP in desk-bound employees. TRIAL REGISTRATION NUMBER: NCT0224687; Pre-results.

A Comprehensive Exercise (COMEX) Intervention to Optimize Exercise Participation for Improving Patient-Centered Outcomes and Physical Functioning in Patients Receiving Hemodialysis: Development and Pilot Testing.

Rationale & Objective: To address the need for an intradialytic exercise program that is easily delivered in clinical setting, engaging and scalable, we developed a novel COMprehensive EXercise (COMEX) program based on input from patients receiving hemodialysis (HD), dialysis staff members and nephrologists. The objective of this study was to determine the feasibility, safety, and acceptance of COMEX during HD. Study Design: Single-arm prospective pilot feasibility study. Setting & Participants: Seventeen patients receiving in-center HD. Intervention: Three-month participation in the COMEX program, which included video-based dialysis chair exercises (aerobic and resistance) integrated with educational and motivational components. Outcomes: Data on recruitment, adherence, safety and acceptability were collected. Additional assessments were performed to evaluate changes in physical functioning, patient-reported symptoms, and objectively measured sleep and physical activity. We also examined the feasibility of obtaining skeletal muscle biopsies and blood samples to explore molecular mechanisms of muscle atrophy and to assess platelet mitochondrial function and adaptation to exercise during HD. Results: Thirteen of the 17 (76%) participants completed the 3-month intervention. The mean participant age was 63.6 ± 15.1 years. In total, 46% of participants were males, and 55% were White. The mean body mass index was 38.7 ± 11.6 kg/m2. There were no reported adverse effects, and the adherence rate to exercise sessions was high with 88% of the sessions completed. Patient satisfaction was high, as 100% of the patients would recommend the program to other dialysis patients. It was feasible to collect data on physical functioning, patient-reported symptoms, and objective sleep and physical activity and to obtain muscle biopsies and blood samples. Limitations: Small sample size, lack of an onsite exercise professional, and technological issues with telemedicine behavioral motivation. Conclusions: The COMEX intradialytic exercise intervention is safe and acceptable to patients, and outcome measures were feasible to obtain. Future studies should consider including exercise professionals to facilitate progression through a personalized exercise protocol. Funding Source: This work is supported by pilot award from P30 DK079307 (PI, Jhamb). Trial Registration: ClinicalTrials.gov, NCT03055299. Plain-Language Summary: We tested a new COMprehensive EXercise (COMEX) program to deliver exercise during dialysis. This 3-month program included video-based dialysis chair exercises (aerobic and resistance) integrated with educational and motivational components. Our study shows COMEX was feasible, had high satisfaction and adherence, and was safe. It was feasible to collect data on physical functioning, patient-reported symptoms, and objective sleep and physical activity and to obtain muscle biopsies and blood samples. Future studies should consider including exercise professionals to facilitate progression through a personalized exercise protocol.

Acceptability and Impact of Office-Based Resistance Exercise Breaks.

BACKGROUND: Breaking up sedentary behavior with standing or walking can decrease discomfort, fatigue, and sleepiness. However, less is known about acceptability and impact of resistance exercise breaks on these outcomes. Therefore, we evaluated the acceptability of resistance exercise breaks and their influence on discomfort, physical and mental fatigue, and sleepiness during occupational sitting. METHODS: Workers completed two 4-hour conditions in random order: prolonged sitting (SIT) and sitting with hourly resistance exercise breaks (REX). All outcomes were measured at baseline and every hour thereafter with five total breaks. Linear mixed models evaluated overall condition effects and differences at each hour. Cohen's d estimated magnitudes of effect. Acceptability was assessed via questionnaire after the REX condition and reported as percentages. FINDINGS: Fourteen adults (age: 53.4 ± 9.5 years, body mass index [BMI]: 30.9 ± 4.8 kg/m2) were enrolled. Although ratings of discomfort, fatigue, and sleepiness were typically lower during REX as compared with SIT, overall outcomes were not significantly different between conditions (p > .05). However, a significant reduction in mental fatigue at hour 4 in favor of the REX condition (ß = -0.48 log-points, p < .05, d = 0.37) was observed. Program acceptability questions revealed the majority (>50%) of participants reported a "4" or "5" on a 5-point Likert-type scale for all questions, indicating high acceptability for implementation. CONCLUSIONS/APPLICATION TO PRACTICE: Resistance exercise breaks had high acceptability and provided preliminary evidence of improving ratings of mental fatigue. More research is needed to better understand the role of resistance training to reduce sedentary behavior.

Considerations for assessing physical function and physical activity in clinical trials during the COVID-19 pandemic.

The coronavirus disease-2019 (COVID-19) pandemic has changed the conduct of clinical trials. For studies with physical function and physical activity outcomes that require in-person participation, thoughtful approaches in transitioning to the remote research environment are critical. Here, we share our experiences in transitioning from in-person to remote assessments of physical function and activity during the pandemic and highlight key considerations for success. Details on the development of the remote assessment protocol, integration of a two-way video platform, and implementation of remote assessments are addressed. In particular, procedural challenges and considerations in transitioning and conducting remote assessments will be discussed in terms of efforts to maintain participant safety, maximize study efficiency, and sustain trial integrity. Plans for triangulation and analysis are also discussed. Although the role of telehealth platforms and research activities in remote settings are still growing, our experiences suggest that adopting remote assessment strategies are useful and convenient in assessing study outcomes during, and possibly even beyond, the current pandemic. Trial register and number: ClinicalTrials.gov [NCT03728257].

Personal and Environmental Contributors to Sedentary Behavior of Older Adults in Independent and Assisted Living Facilities.

Sedentary behavior is associated with negative health outcomes and unhealthy aging. Older adults are the most sedentary age group, and decreasing sitting time represents an intervention target for improving health. Determinants of sedentary behavior have been examined in older adults living in their own homes, yet less is known about sedentary behavior of older adults in residential care facilities. The purpose of this study was to explore factors contributing to sedentary behavior among residents of independent and assisted living facilities. We conducted eight focus groups with residents (n = 44) and semi-structured interviews with staff (n = 6) across four living facilities. Audio recordings were transcribed and analyzed using an iterative, inductive approach. Three salient themes were identified. Residents and staff both viewed sedentary behavior negatively unless it was in the context of social engagement. Additionally, fear of falling was discussed as a significant contributor to sedentary behavior. Finally, residents felt the community living environment contributed to their sedentary behavior while staff did not. Our findings provide valuable insight for designing targeted interventions for older adults in residential facilities and suggest thinking beyond the individual and considering environmental influences on sedentary behavior in the residential care setting.

Accuracy of Objective Physical Activity Monitors in Measuring Steps in Older Adults.

Objective: The aim of this study is to evaluate accuracy of research activity monitors in measuring steps in older adults with a range of walking abilities. Method: Participants completed an initial assessment of gait speed. The accuracy of each monitor to record 100 steps was assessed across two walking trials. Results: In all, 43 older adults (age 87 ± 5.7 years, 81.4% female) participated. Overall, the StepWatch had the highest accuracy (99.0% ± 1.5%), followed by the ActivPAL (93.7% ± 11.1%) and the Actigraph (51.4% ± 35.7%). The accuracy of the Actigraph and ActivPAL varied according to assistive device use, and the accuracy of all three monitors differed by gait speed category (all p < .05). StepWatch was highly accurate (⩾97.7) across all conditions. Discussion: The StepWatch and ActivPAL monitor were reasonably accurate in measuring steps in older adults who walk slowly and use an assistive device. The Actigraph significantly undercounted steps in those who walk slow or use an assistive device. Researchers should consider gait speed and the use of assistive devices when selecting an activity monitor.

Effect of Using a Sit-Stand Desk on Ratings of Discomfort, Fatigue, and Sleepiness Across a Simulated Workday in Overweight and Obese Adults.

BACKGROUND: Limited research examines the influence of sit-stand desks on ratings of discomfort, sleepiness, and fatigue. This study evaluated the time course of these outcomes over 1 day. METHODS: Adults (N = 25) completed a randomized cross-over study in a laboratory with two 8-hour workday conditions: (1) prolonged sitting (SIT) and (2) alternating sitting and standing every 30 minutes (SIT-STAND). Sleepiness was assessed hourly. Discomfort, physical fatigue, and mental fatigue were measured every other hour. Linear mixed models evaluated whether these measures differed across conditions and the workday. Effect sizes were calculated using Cohen's d. RESULTS: Participants were primarily white (84%) males (64%), with mean (SD) body mass index of 31.9 (5.0) kg/m2 and age 42 (12) years. SIT-STAND resulted in decreased odds of discomfort (OR = 0.37, P = .01) and lower overall discomfort (ß = -0.19, P < .001, d = 0.42) versus SIT. Discomfort during SIT-STAND was lower in the lower and upper back, but higher in the legs (all Ps< .01, d = 0.26-0.42). Sleepiness (ß = -0.09, P = .01, d = 0.15) and physical fatigue (ß = -0.34, P = .002, d = 0.34) were significantly lower in SIT-STAND. Mental fatigue was similar across conditions. CONCLUSIONS: Sit-stand desks may reduce acute levels of sleepiness, physical fatigue, and both overall and back discomfort. However, levels of lower extremity discomfort may be increased with acute exposure.

Impact of Intensive Lifestyle Intervention on Disability-Free Life Expectancy: The Look AHEAD Study.

OBJECTIVE: The impact of weight loss intervention on disability-free life expectancy in adults with diabetes is unknown. We examined the impact of a long-term weight loss intervention on years spent with and without physical disability. RESEARCH DESIGN AND METHODS: Overweight or obese adults with type 2 diabetes age 45-76 years (n = 5,145) were randomly assigned to a 10-year intensive lifestyle intervention (ILI) or diabetes support and education (DSE). Physical function was assessed annually for 12 years using the 36-Item Short Form Health Survey. Annual incidence of physical disability, mortality, and disability remission were incorporated into a Markov model to quantify years of life spent active and physically disabled. RESULTS: Physical disability incidence was lower in the ILI group (6.0% per year) than in the DSE group (6.8% per year) (incidence rate ratio 0.88 [95% CI 0.81-0.96]), whereas rates of disability remission and mortality did not differ between groups. ILI participants had a significant delay in moderate or severe disability onset and an increase in number of nondisabled years (P < 0.05) compared with DSE participants. For a 60-year-old, this effect translates to 0.9 more disability-free years (12.0 years [95% CI 11.5-12.4] vs. 11.1 years [95% CI 10.6-11.7]) but no difference in total years of life. In stratified analyses, ILI increased disability-free years of life in women and participants without cardiovascular disease (CVD) but not in men or participants with CVD. CONCLUSIONS: Long-term lifestyle interventions among overweight or obese adults with type 2 diabetes may reduce long-term disability, leading to an effect on disability-free life expectancy but not on total life expectancy.

Long-term impact of intensive lifestyle intervention on cognitive function assessed with the National Institutes of Health Toolbox: The Look AHEAD study.

INTRODUCTION: This study sought to determine whether 10 years of assignment to intensive lifestyle intervention (ILI) relative to diabetes support and education leads to better cognition. We examine intervention effects overall and among clinical subgroups, and report correlations between computer-administered and interviewer-administered cognitive batteries. METHODS: The Action for Health in Diabetes (Look AHEAD) was a 16-site randomized controlled trial with overweight/obese individuals (aged 45-76) who had type 2 diabetes. The NIH Toolbox Cognition Battery tests developed to measure cognition across the lifespan were used to evaluate cognition. Results were compared with standard paper-and-pencil tests. The Toolbox and paper-and-pencil tests were administered an average of 10.9 years after randomization to 1002 participants. RESULTS: Toolbox measures significantly correlated with interviewer-administered measures, with the strongest correlations between the Toolbox Fluid Cognition Composite and Trails B (r = -0.64, P < .0001) and Digit Symbol Coding (r = 0.63, P < .0001), and between the Toolbox Dimensional Change Card Sort (r = 0.55, P < .0001) and the Digit Symbol Coding test. Overall, ILI and diabetes support and education groups had similar adjusted mean cognitive outcomes (P > .05 for all). Subgroup analyses identified different intervention effects within baseline body mass index groups for Picture Sequence Memory (P = .01), within baseline cardiovascular disease groups for Picture Vocabulary (P = .01) and Fluid Cognition Composite (P = .02) measures, and within baseline age groups for Picture Vocabulary (P = .02). DISCUSSION: Correlations between Toolbox and interviewer-administered outcomes provide a measure of internal validity. Findings suggest no overall effect of the intervention on cognition and that an ILI resulting in weight loss may have negative implications for cognition in individuals aged ≥60, with previous history of cardiovascular disease, and those with body mass index ≥40.

Effects of Longitudinal Glucose Exposure on Cognitive and Physical Function: Results from the Action for Health in Diabetes Movement and Memory Study.

OBJECTIVES: To test whether average long-term glucose exposure is associated with cognitive and physical function in middle-aged and younger-old adults with type 2 diabetes mellitus. DESIGN: Prospective cohort study. SETTING: Data obtained as part of the Action for Health in Diabetes (Look AHEAD) trial (NCT00017953) and Look AHEAD Movement and Memory ancillary study (NCT01410097). PARTICIPANTS: Overweight and obese individuals with type 2 diabetes mellitus aged 45 to 76 at baseline (N = 879). MEASUREMENTS: Glycosylated hemoglobin (HbA1c) was measured at regular intervals over 7 years, and objective measures of cognitive function (Trail-Making Test, Modified Stroop Color-Word Test, Digit Symbol-Coding, Rey Auditory Verbal Learning Test, Modified Mini-Mental State Examination) and physical function (Short Physical Performance Battery, expanded Physical Performance Battery, 400-m and 20-m gait speed) and strength (grip and knee extensor strength) were assessed at the Year 8 or 9 follow-up examination. RESULTS: Average HbA1c exposure was 7.0 ± 1.1% (53 ± 11.6 mmol/mol), with 57% of participants classified as having HbA1c levels of less than 7% (<53 mmol/mol), 27% having levels of 7% to 8% (53-64 mmol/mol), and 16% having levels of greater than 8% (>64 mmol/mol). After adjustment for age, sex, race, education, smoking status, alcohol intake, knee pain, physical fitness, body mass index, diabetes mellitus medication and statin use, ancillary year visit, and study arm and site, higher HbA1c was associated with worse physical but not cognitive function. Further adjustment for prevalent diabetes mellitus-related comorbidities made all associations nonsignificant. Results did not differ when stratified according to participant baseline age (<60 vs ≥ 60). CONCLUSION: Results presented here suggest that, in the absence of diabetes mellitus-related complications, longitudinal glucose exposure is not associated with future cognitive and physical function. Optimal management of diabetes mellitus-related comorbidities may prevent or reduce the burden of disability associated with type 2 diabetes mellitus.

Delivering an in-Home Exercise Program via Telerehabilitation: A Pilot Study of Lung Transplant Go (LTGO).

We evaluated the feasibility, safety, system usability, and intervention acceptability of Lung Transplant Go (LTGO), an 8-week in-home exercise intervention for lung transplant recipients using a telerehabilitation platform, and described changes in physical function and physical activity from baseline to post-intervention. The intervention was delivered to lung transplant recipients in their home via the Versatile and Integrated System for TeleRehabilitation (VISYTER). The intervention focused on aerobic and strengthening exercises tailored to baseline physical function. Participants improved walk distance (6-minute walk distance), balance (Berg Balance Scale), lower body strength (30-second chair stand test) and steps walked (SenseWear Armband®). No adverse events were reported. Participants rated the program highly positively in regard to the technology and intervention. The telerehabilitation exercise program was feasible, safe, and acceptable. Our findings provide preliminary support for the LTGO intervention to improve physical function and promote physical activity in lung transplant recipients.

Definition, measurement, and health risks associated with sedentary behavior.

PURPOSE AND METHODS: Although evidence is accumulating that sedentary behavior (SB), independent of moderate-to-vigorous intensity physical activity (MVPA), is associated with cardiometabolic and aging outcomes in adults, several gaps present opportunities for future research. This article reports on the "Research Evidence on Sedentary Behavior" session of the Sedentary Behavior: Identifying Research Priorities workshop, sponsored by the National Heart, Lung, and Blood Institute and the National Institute on Aging, which aimed to identify priorities in SB research. RESULTS AND CONCLUSIONS: A consensus definition of SB has not yet been established, although agreement exists that SB is not simply all behaviors other than MVPA. The two most common definitions are as follows: one based solely on intensity (<1.5 metabolic equivalents [METs]) and another which combines low intensity (≤1.5 METs) with a seated or reclining posture. Thus, for the definition of SB, evaluation of whether or not to include a postural component is a research priority. SB assessment methodologies include self-report and objective measurement, each offering distinct information. Therefore, evaluation, standardization, and comparison across self-report and objective assessment methods are needed. Specific priorities include the development and validation of novel devices capable of assessing posture and standardization of research practices for SB assessment by accelerometry. The prospective evidence that SB relates to health outcomes is limited in that SB is almost exclusively measured by self-report. The lack of longitudinal studies with objectively measured SB was recognized as a major research gap, making examination of the association between objectively measured SB and adverse health outcomes in longitudinal studies a research priority. Specifically, studies with repeated measures of SB, evaluating dose-response relationships, with inclusion of more diverse populations are needed.

A long-term intensive lifestyle intervention and physical function: the look AHEAD Movement and Memory Study.

OBJECTIVE: To assess the long-term effects of an intensive lifestyle intervention on physical function using a randomized post-test design in the Look AHEAD trial. METHODS: Overweight and obese (BMI ≥ 25 kg m(-2)) middle-aged and older adults (aged 45-76 years at enrollment) with type 2 diabetes (n = 964) at four clinics in Look AHEAD, a trial evaluating an intensive lifestyle intervention (ILI) designed to achieve weight loss through caloric restriction and increased physical activity compared to diabetes support and education (DSE), underwent standardized assessments of performance-based physical function including an expanded short physical performance battery (SPPBexp ), 20-m and 400-m walk, and grip and knee extensor strength 8 years post-randomization, during the trial's weight maintenance phase. RESULTS: Eight years post-randomization, individuals randomized to ILI had better SPPBexp scores [adjusted mean (SE) difference: 0.055 (0.022), P = 0.01] and faster 20-m and 400-m walk speeds [0.032 (0.012) m s(-1) , P = 0.01, and 0.025 (0.011) m s(-1) , P = 0.02, respectively] compared to those randomized to DSE. Achieved weight loss greatly attenuated the group differences in physical function, and the intervention effect was no longer significant. CONCLUSIONS: An intensive lifestyle intervention has long-term benefits for mobility function in overweight and obese middle-aged and older individuals with type 2 diabetes.

Long-term impact of behavioral weight loss intervention on cognitive function.

BACKGROUND: It is unknown whether intentional weight loss provides long-term benefits for cognitive function. METHODS: An ancillary study to a randomized controlled clinical trial was conducted in overweight and obese individuals (N = 978), aged 45-76 years at enrollment, with type 2 diabetes. An intensive behavioral intervention designed to promote and maintain weight loss through caloric restriction and increased physical activity was compared with diabetes support and education. Standardized assessments of cognitive function were collected an average of 8.1 years after trial enrollment. RESULTS: Participants assigned to intensive lifestyle intervention lost a mean (SE) 11.1% (0.4%) and 7.2% (0.5%) of weight at Years 1 and 8, respectively, compared with 1.0% (0.2%) and 3.3% (0.5%) in the control group (p < .001). Covariate-adjusted mean composite cognitive function test scores were similar for the two groups (p = .69), and no significant differences were found for any individual cognitive test. There was some evidence of a differential effect (nominal interaction p = .008) for a prespecified comparison: Intensive lifestyle intervention was associated with a relative mean benefit for composite cognitive function of 0.276 (95% confidence interval: 0.033, 0.520) SDs among individuals with body mass index less than 30 kg/m(2) at baseline compared with a relative mean deficit of 0.086 (-0.021, 0.194) SDs among individuals with body mass more than or equal to 30 kg/m(2). CONCLUSIONS: Eight years of intensive lifestyle intervention did not alter cognitive function in obese adults with type 2 diabetes; however, there was evidence for benefit among overweight but not obese individuals. Changes in cognition were not assessed in this cross-sectional study.

Association of body mass index with self-report and performance-based measures of balance and mobility.

BACKGROUND: The incidence of obesity is increasing in older adults, with associated worsening in the burden of disability. Little is known about the impact of body mass index (BMI) on self-report and performance-based balance and mobility measures in older adults. OBJECTIVE: The purposes of this study were (1) to examine the association of BMI with measures of balance and mobility and (2) to explore potential explanatory factors. DESIGN: This was a cross-sectional, observational study. METHODS: Older adults (mean age=77.6 years) who participated in an ongoing observational study (N=120) were classified as normal weight (BMI=18.5-24.9 kg/m(2)), overweight (BMI=25.0-29.9 kg/m(2)), moderately obese (BMI=30.0-34.9 kg/m(2)), or severely obese (BMI ≥ 35 kg/m(2)). Body mass index data were missing for one individual; thus, data for 119 participants were included in the analysis. Mobility and balance were assessed using self-report and performance-based measures and were compared among weight groups using analysis of variance and chi-square analysis for categorical data. Multiple linear regression analysis was used to examine the association among BMI, mobility, and balance after controlling for potential confounding variables. RESULTS: Compared with participants who were of normal weight or overweight, those with moderate or severe obesity were less likely to report their mobility as very good or excellent (52%, 55%, 39%, and 6%, respectively); however, there was no difference in self-report of balance among weight groups. Participants with severe obesity (n=17) had the lowest levels of mobility on the performance-based measures, followed by those who were moderately obese (n=31), overweight (n=42), and of normal weight (n=29). There were no differences on performance-based balance measures among weight groups. After controlling for age, sex, minority status, physical activity level, education level, and comorbid conditions, BMI still significantly contributed to mobility (ß=-.02, adjusted R(2)=.41). CONCLUSIONS: Although older adults with severe obesity were most impaired, those with less severe obesity also demonstrated significant decrements in mobility.

The Influence of Body Mass Index on Self-report and Performance-based Measures of Physical Function in Adult Women.

PURPOSE: Little is known about limitations in physical function across BMI categories in middle aged women using both self-report and performance-based measures. Furthermore, the impact of BMI on the measurement of function has not been explored. The purpose of this study was to assess physical function in adult women across BMI categories using self-report and performance-based measures and determine the influence of BMI on the relationship between the measures. METHODS: Fifty sedentary females (10 in each BMI category: normal weight, overweight, obese class I, II, and III) aged 51.2 ± 5.4 years participated. Assessments included demographics, past medical history, physical activity level, BMI, and self-report (Late Life Function and Disability Instrument) and performance-based measures of physical function (6-Minute Walk Test, timed chair rise, gait speed). Physical function was compared between BMI categories using analysis of variance. The influence of BMI on the relationship of self-report and performance-based measures was analyzed using linear regression. RESULTS: Compared to those that were normal weight or overweight, individuals with obesity scored lower on the self-report measure of physical function (LLFDI) for capability in participating in life tasks and ability to perform discrete functional activities. On the performance-based measures, the individuals with obesity had slower gait speed compared to the normal and overweight weight groups. For the 6-Minute Walk Test and timed chair stands, individuals with obesity had poorer performance compared to those who were normal weight. Linear regression analyses revealed that BMI attenuated the relationship between the self-report and performance-based measures by approximately 50%. CONCLUSIONS: While those with severe obesity were most impaired, adult women with less severe obesity also demonstrated significant decrements in physical function.