Effect of Baseline BMI and IL-6 Subgroup Membership on Gait Speed Response to Caloric Restriction in Older Adults with Obesity.

BACKGROUND: Prior work shows caloric restriction (CR) can improve physical function among older adults living with obesity. However, the contribution of starting weight and inflammatory burden to CR-associated functional improvements is unclear. The primary purpose of this study was to determine if CR-associated gait speed change varied by body mass index (BMI) and plasma interleukin 6 (IL-6) at baseline and secondarily to determine the contribution of BMI change and IL-6 change to gait speed change. DESIGN, SETTING, PARTICIPANTS: Data from eight randomized control trials were pooled, with 1184 participants randomized to CR (n=661) and No CR (n=523) conditions. All studies assessed outcomes before and five or six months after assignment to CR or No CR. MEASUREMENTS: BMI and IL-6 were assessed at baseline using standard procedures. Gait speed was assessed with the six-minute walk test or 400m walk test. Baseline BMI/IL-6 subgroups were constructed using BMI≥35 kg/m2 and IL-6>2.5 pg/mL thresholds. Participants with BMI≥35 kg/m2 were grouped into class 2+ obesity and BMI<35 kg/m2 into class 1- obesity; IL-6>2.5 pg/mL were grouped into high IL-6, and <2.5 pg/mL as low IL-6 (class 2+ obesity/high IL-6: n=288, class 2+ obesity/low IL-6: n=143, class 1- obesity/high IL-6: n=354, or class 1- obesity/low IL-6: n=399). All analyses used adjusted general linear models. RESULTS: Gait speed significantly improved with CR versus non-CR [mean difference: +0.02 m/s (95% CI: 0.01, 0.04)]. CR assignment significantly interacted with BMI/IL-6 subgroup membership (p=0.03). Greatest gait speed improvement was observed in the class 2+ obesity/high IL-6 subgroup [+0.07 m/s (0.03, 0.10)]. No other subgroups observed significant gait speed change. For each unit decrease in BMI, gait speed change increased by +0.02 m/s (p<0.001; R2=0.26), while log IL-6 change did not significantly affect gait speed change [+0.01 m/s (p=0.20)]. CONCLUSIONS: Only the class 2+ obesity/high IL-6 subgroup significantly improved gait speed in response to CR. Improvement in gait speed in this subgroup was driven by a larger decrease in BMI, but not IL-6, in response to CR. Individuals with class 2+ obesity and high IL-6 are most likely to show improved gait speed in response to CR, with improvement predominantly driven by reductions in BMI.

The Effects of a Pain Management-Focused Mobile Health Behavior Intervention on Older Adults' Self-efficacy, Satisfaction with Functioning, and Quality of Life: a Randomized Pilot Trial.

BACKGROUND: This report investigates the impact of a remote physical activity intervention on self-efficacy, satisfaction with functioning, and health-related quality of life (HRQOL) as assessed by the SF-36 in obese older adults with chronic pain. The intervention was group-mediated in nature and based in social cognitive theory and mindfulness-based relapse prevention. METHODS: Participants (N = 28; 70.21 ± 5.22 years) were randomly assigned to receive either the active intervention, which focused on reducing caloric intake and increasing steps across the day or to a waitlist control condition. RESULTS: Over 12 weeks, intervention participants reported a moderate, positive improvement in self-efficacy for walking relative to control. They also reported large magnitude improvements in satisfaction for physical functioning as well as improvements on pain and the physical functioning subscales of the SF-36. CONCLUSIONS: These findings expand on previous research showing similar effects in response to structured exercise, this time via a protocol that is likely to be scalable and sustainable for many older adults. Additional work on larger and more diverse samples is warranted.

Relationships between respiratory sinus arrhythmia and stress in college students.

The purpose of this study was to examine the relationships between university students' respiratory sinus arrhythmia (RSA) profiles and both retrospective and momentary ratings of stress. Participants were undergraduate students enrolled in an introductory health science course (N = 64). Participants provided RSA data at rest (tonic) and following an orthostatic challenge (phasic), completed the 10-item Perceived Stress Scale (PSS), and completed 6 daily ecological momentary assessments (EMA) of stress for 1 week. Higher tonic RSA was associated with lower perceived stress assessed via PSS and average EMA responses. Those with higher tonic RSA did not differ in their experience of stress across the week, whereas those with lower tonic RSA experienced increased stress across the week, and these trajectories varied as a function of phasic responses. These findings suggest a need for greater emphasis on behavioral strategies for maintaining and enhancing autonomic nervous system health among college students.

Empowered with Movement to Prevent Obesity & Weight Regain (EMPOWER): Design and methods.

Promoting lasting weight loss among older adults is an important public health challenge. Participation in physical activity aids in weight loss and is important for the maintenance of physical function and quality of life. However, traditional intensive lifestyle interventions place a focus on discrete bouts of structured activity, leaving much of the remainder of the day for sedentary behavior. Structured exercise and weight loss programs often produce short-term weight loss that is typically followed by weight regain, and older adults are more likely to regain weight as fat mass rather than lean mass. Preliminary evidence suggests a focus on day-long movement intended to minimize time spent sitting produces better short-term weight loss and weight maintenance. Herein we describe the design and methods for a three-arm randomized controlled trial comparing mHealth-supported weight loss (WL) + structured exercise (EX); WL + a novel daily movement intervention (SitLess); and WL + EX + SitLess. Older adults (N = 180) will be randomly assigned to one of the three interventions, each comprised of a 6-month intensive phase; a 3-month transition phase; and a 9-month maintenance phase. The primary aim of the study is to determine whether the addition of SitLess to a traditional intensive lifestyle intervention comprised of dietary weight loss and structured exercise produces a larger 18-month reduction in body weight relative to WL + EX and WL + SitLess.

Development of Subject-Specific Proximal Femur Finite Element Models Of Older Adults with Obesity to Evaluate the Effects of Weight Loss on Bone Strength.

STUDY BACKGROUND: Recommendation of intentional weight loss in older adults remains controversial, due in part to the loss of bone mineral density (BMD) known to accompany weight loss. While finite element (FE) models have been used to assess bone strength, these methods have not been used to study the effects of weight loss. The purpose of this study is to develop subject-specific FE models of the proximal femur and study the effect of intentional weight loss on bone strength. METHODS: Computed tomography (CT) scans of the proximal femur of 25 overweight and obese (mean BMI=29.7 ± 4.0 kg/m2), older adults (mean age=65.6 ± 4.1 years) undergoing an 18-month intentional weight loss intervention were obtained at baseline and post-intervention. Measures of volumetric BMD (vBMD) and variable cortical thickness were derived from each subject CT scan and directly mapped to baseline and post-intervention models. Subject-specific FE models were developed using morphing techniques. Bone strength was estimated through simulation of a single-limb stance and sideways fall configuration. RESULTS: After weight loss intervention, there were significant decreases from baseline to 18 months in vBMD (total hip: -0.024 ± 0.013 g/cm3; femoral neck: -0.012 ± 0.014 g/cm3), cortical thickness (total hip: -0.044 ± 0.032 mm; femoral neck: -0.026 ± 0.039 mm), and estimated strength (stance: -0.15 ± 0.12 kN; fall: -0.04 ± 0.06 kN). Adjusting for baseline bone measures, body mass, and gender, correlations were found between weight change and change in total hip and femoral neck cortical thickness (all p<0.05). For every 1 kilogram of body mass lost cortical thickness in the total hip and femoral neck decreased by 0.003 mm and 0.004 mm, respectively. No significant correlations were present for the vBMD or strength data. CONCLUSION: The developed subject-specific FE models could be used to better understand the effects of intentional weight loss on bone health.

Obesity, intentional weight loss and physical disability in older adults.

We examine obesity, intentional weight loss and physical disability in older adults. Based on prospective epidemiological studies, body mass index exhibits a curvilinear relationship with physical disability; there appears to be some protective effect associated with older adults being overweight. Whereas the greatest risk for physical disability occurs in older adults who are ≥class II obesity, the effects of obesity on physical disability appears to be moderated by both sex and race. Obesity at age 30 years constitutes a greater risk for disability later in life than when obesity develops at age 50 years or later; however, physical activity may buffer the adverse effects obesity has on late life physical disability. Data from a limited number of randomized clinical trials reinforce the important role that physical activity plays in weight loss programmes for older adults. Furthermore, short-term studies have found that resistance training may be particularly beneficial in these programmes as this mode of exercise attenuates the loss of fat-free mass during caloric restriction. Multi-year randomized clinical trials are needed to examine whether weight loss can alter the course of physical disablement in aging and to determine the long-term feasibility and effects of combining resistance exercise with weight loss in older adults.

Treatment of minor depression in older adults: a pilot study comparing sertraline and exercise.

The purpose of this study was to conduct a pilot clinical trial to test the feasibility and efficacy of an exercise program and anti-depressant treatment compared with usual care in improving the emotional and physical functioning of older adults with minor depression. Participants were 37 older adults with minor depression who were randomized to exercise, sertraline, or usual care; 32 participants completed the 16-week study. Outcomes included measures of both emotional (clinician and self-report) and physical (observed and self-report) functioning. There were trends for the superiority of the exercise and sertraline conditions over usual care in improving SF-36 mental health scores and clinician-rated depression scores. Individuals in the exercise condition showed greater improvements in physical functioning than individuals in the usual care condition. Both sertraline and exercise show promise as treatments for late-life minor depression. However, exercise has the added benefit of improving physical functioning as well.

Physical activity and quality of life in older adults.

Although there has been increased research and clinical attention given to the effects that physical activity has on quality of life among older adults, there is a lack of consistency surrounding the use of this term. As a result, attempts to examine what causes change in quality of life have been limited. This article critically reviews the literature on physical activity and quality of life in older adults. In so doing, attention is given to both quality of life as a psychological construct represented by life satisfaction as well as a clinical and geriatric outcome represented by the core dimensions of health status or health-related quality of life. The literature is also examined to identify potential mediators and moderators in the physical activity and quality-of-life relationship. Discussion of possible mediating variables reinforces the important role of perception when considering the beneficial effects that physical activity has on quality of life. From a public health perspective, understanding what may cause change in quality of life has significant implications for the design, implementation, and promotion of physical activity programs for older adults.

Physical exercise and the prevention of disability in activities of daily living in older persons with osteoarthritis.

BACKGROUND: The prevention of disability in activities of daily living (ADL) may prolong older persons' autonomy (older persons are defined in this study as those aged > or =60 years). However, proved preventive strategies for ADL disability are lacking. A sedentary lifestyle is an important cause of disability. This study examines whether an exercise program can prevent ADL disability. METHODS: A 2-center, randomized, single-blind, controlled trial was conducted in which participants were assigned to an aerobic exercise program, a resistance exercise program, or an attention control group. Of the 439 community-dwelling persons aged 60 years or older with knee osteoarthritis originally recruited, the 250 participants initially free of ADL disability were used for this study. Incident ADL disability, defined as developing difficulty in transferring from a bed to a chair, eating, dressing, using the toilet, or bathing, was assessed quarterly during 18 months of follow-up. RESULTS: The cumulative incidence of ADL disability was lower in the exercise groups (37.1%) than in the attention control group (52.5%) (P =.02). After adjustment for demographics and baseline physical function, the relative risk of incident ADL disability for assignment to exercise was 0.57 (95% confidence interval, 0.38-0.85; P =.006). Both exercise programs prevented ADL disability; the relative risks were 0.60 (95% confidence interval, 0.38-0.97; P =.04) for resistance exercise and 0.53 (95% confidence interval, 0.33-0.85; P =.009) for aerobic exercise. The lowest ADL disability risks were found for participants with the highest compliance to exercise. CONCLUSIONS: Aerobic and resistance exercise may reduce the incidence of ADL disability in older persons with knee osteoarthritis. Exercise may be an effective strategy for preventing ADL disability and, consequently, may prolong older persons' autonomy.

Modifiers of change in physical functioning in older adults with knee pain: the Observational Arthritis Study in Seniors (OASIS).

OBJECTIVE: To ascertain predictors of decline in physical functioning among older adults reporting knee pain. METHODS: The Observational Arthritis Study in Seniors was a longitudinal study of 480 adults over 65 years of age. Measurements of strength, sociodemographic characteristics, disease burden (including radiographic knee osteoarthritis [OA]), self-reported disability, and functional limitations were obtained on participants at baseline and at 15 and 30 months. RESULTS: Radiographic evidence of OA at baseline was moderately associated with an increased decline in both transfer (P = 0.06) and ambulatory-based performance tasks (P = 0.04) but not in self-reported disability. This effect disappeared after accounting for baseline levels of knee pain intensity and knee strength. CONCLUSION: Knee pain intensity and knee strength may mediate the relationship between radiographic evidence of knee OA and change in performance. Although it is not clear whether joint disease precedes or follows a decline in muscular strength, these results may help to identify subpopulations of older persons with knee OA who may benefit from interventions aimed at slowing the progression of disability related to transfer and ambulatory-based tasks.

Self-efficacy and the progression of functional limitations and self-reported disability in older adults with knee pain.

OBJECTIVES: The prospective relationships between self-efficacy beliefs, in conjunction with measures of knee pain and knee strength, and subsequent decline in both physical performance and self-reported disability among older adults with knee pain were examined. METHODS: In this prospective epidemiological trial, 480 men and women aged 65 years and older who had knee pain on most days of the week and difficulty with daily activity were followed for 30 months. RESULTS: There was a significant interaction of baseline self-efficacy with baseline knee strength in predicting both self-reported disability and stair climb performance. Participants who had low self-efficacy and low strength at baseline had the largest 30-month decline in these outcomes. DISCUSSION: These data underscore the important role that self-efficacy beliefs play in understanding functional decline with chronic disease and aging. Self-efficacy beliefs appear to be most important to functional decline in older adults when they are challenged by muscular weakness in the lower extremities.

Gender moderates the effects of exercise therapy on health-related quality of life among COPD patients.

STUDY OBJECTIVES: To determine whether long-term treatment with exercise therapy results in more favorable, disease-specific, health-related quality of life (HRQL) compared with short-term treatment with exercise therapy; and to determine whether there are gender differences in disease-specific HRQL among individuals randomized into the two treatment groups. DESIGN: Randomized clinical trial. SETTING: Center-based exercise therapy unit at a university. PARTICIPANTS: One hundred forty patients with COPD; 118 completed trial. INTERVENTIONS: Short-term exercise therapy (3 months); long-term exercise therapy (18 months). MEASUREMENTS: Chronic Disease Respiratory Questionnaire (CRQ). RESULTS: After 3 months of treatment, there were significant improvements in all CRQ scores for men and women (p < 0.01), and for the total sample (p < 0.01). At 18 months, individuals randomized into the long-term group had significantly more favorable scores than the short-term group for dyspnea (p = 0.03), fatigue (p < 0.01), emotional function (p = 0.04), and mastery (p = 0.04). However, these effects were moderated by gender. That is, men in the long-term group reported significantly more favorable scores than men in the short-term group for dyspnea (0.04), fatigue (p < 0.001), emotional function (p = 0.02), and mastery (p = 0.02). At the 18-month assessment, there were no differences between long-term and short-term exercise therapy for women on any of the subscales of the CRQ. CONCLUSIONS: Taken collectively, the CRQ data demonstrate that long-term exercise therapy has little added benefit for women over short-term exercise therapy; however, men derive significant benefits from extended training.

Mediators of Increased Physical Activity and Change in Subjective Well-being: Results from the Activity Counseling Trial (ACT).

The purpose of this study was to examine whether change in satisfaction with physical function (SF), satisfaction with physical appearance (SA), and self-efficacy (SE) mediate the effects that increased physical activity has on change in subjective well-being (SWB). Participants in this investigation consisted of 854 men (n = 471) and women (n = 383) who took part in the Activity Counseling Trial (ACT). ACT was a 24-month multicenter, randomized controlled trial to evaluate the effectiveness of interventions to promote physical activity in the primary care setting. Participants were assigned to one of three treatments: standard care control, staff-assisted intervention, or staff-counseling intervention. Results revealed that, irrespective of treatment arm, change in physical activity was related to change in SBW and to change in all mediators of interest. A statistical test of mediation revealed that the influence of change in physical activity on SWB was due to change in all three mediators with change in SF making the greatest contribution to the model.

An examination of theory and behavior change in randomized clinical trials.

This paper underscores the important role played by theory-based mediating variables in randomized clinical trials. Indeed, it is essential that we know what mediating variables are relevant for particular outcomes in randomized clinical trials and that we design interventions to optimize change in the mediators of interest. Yet, knowledge of the pivotal mediating variables in behavior change does not imply that we know how to intervene effectively. This gap may be due to the fact that existing research typically has been designed to garner support for theory, as opposed to testing support for behavior change strategies that are based on theory. In addition, we argue that there are important mediating variables in behavior change that have not been given systematic attention in theory development. For example, behavior change must be viewed as a collaborative process, and participants' perceptions concerning the feasibility of change is important to motivational processes in randomized clinical trials. Control Clin Trials 2000;21:164S-170S

Predictors of adherence to behavior change interventions in the elderly.

Considering factors at the individual, interpersonal, and environmental level may enhance adherence to interventions in the elderly. A collaborative practitioner-participant relationship is also essential. Control Clin Trials 2000;21:200S-205S

Physical activity, functional limitations, and disability in older adults.

OBJECTIVES: To explore initially how low levels of physical activity influence lower body functional limitations in participants of the Longitudinal Study of Aging. Changes in functional limitations are used subsequently to predict transitions in the activities of daily living/instrumental activities of daily living (ADL/IADL) disability, thus investigating a potential pathway for how physical activity may delay the onset of ADL/IADL disability and, thus, prolong independent living. DESIGN: Analysis of a complex sample survey of US civilian, noninstitutionalized population aged 70 years and older in 1984, with repeated interviews in 1986, 1988, and 1990. SETTING AND PARTICIPANTS: Analyses concentrated on 5151 men and women targeted for interview at all four LSOA interviews. MEASUREMENTS: Characteristics used in analyses: gender, age, level of physical activity, comorbid conditions including the presence of hypertension, diabetes, arthritis, and atherosclerotic heart disease, levels of functional limitations, and ADL/IADL disability. RESULTS: Transitional models provide evidence that older adults who have varying levels of disability and who report at least a minimal level of physical activity experience a slower progression in functional limitations (OR = .45, P < .001 for severe vs less severe limitations). This low level of physical activity, through its influence on changes in functional limitations, is shown to slow the progression of ADL/IADL disability. CONCLUSIONS: Results from analyses provide supporting evidence that functional limitations can mediate the effect that physical activity has on ADL/IADL disability. These results contribute further to the increasing data that seem to suggest that physical activity can reduce the progression of disability in older adults.

Effects of leadership style and group dynamics on enjoyment of physical activity.

PURPOSE: The primary purpose of this study was to examine the independent and combined effects of leadership style and group dynamics on the enjoyment of physical activity. DESIGN: A completely randomized 2 x 2 factorial design was used in which the manipulation of "leadership style" (socially enriched vs. bland) was crossed with a manipulation of "group dynamics" (socially enriched vs. bland). SETTING: The study was conducted in an aerobics studio on a university campus. SUBJECTS: The sample included 48 male and 42 female undergraduate students who were moderately active. INTERVENTION: Each participant was involved in a single session of step aerobics. A female graduate student provided either an enriched or bland series of interactions to manipulate leadership style, and a trained group of planted undergraduates was used to promote either an enriched or bland group environment. MEASURES: The outcome measures of interest were enjoyment and the probability of engaging in a similar activity in the future. RESULTS: Participants in the enriched leadership style plus enriched group dynamics condition reported higher enjoyment than did participants in the other three conditions. On average, the level of enjoyment was 22.07% higher in this condition than in the other three conditions (p < .001). The probability of future involvement was 13.93% higher for participants in the enriched group environment, irrespective of leadership style (p < .03). CONCLUSIONS: Enjoyment during physical activity is optimized when a positive and supportive leadership style is coupled with an enriched and supportive group environment. Future research is required to extend these findings to other activities and populations.

Exercise and weight loss in obese older adults with knee osteoarthritis: a preliminary study.

OBJECTIVE: The purposes of this pilot study were to determine if a combined dietary and exercise intervention would result in significant weight loss in older obese adults with knee osteoarthritis, and to compare the effects of exercise plus dietary therapy with exercise alone on gait, strength, knee pain, biomarkers of cartilage degradation, and physical function. DESIGN: Single-blind, two-arm, randomized clinical trial conducted for 24 weeks. SETTING: A university health and exercise science center. PARTICIPANTS: Twenty-four community-dwelling obese older adults aged > or = 60 years, body mass index > or = 28, knee pain, radiographic evidence of knee osteoarthritis, and self-reported physical disability. INTERVENTION: Randomization into two groups: exercise and diet (E&D) and exercise alone (E). Exercise consisted of a combined weight training and walking program for 1 hour three times per week. The dietary intervention included weekly sessions with a nutritionist utilizing cognitive-behavior modification to change dietary habits to reach a group goal of an average weight loss of 15 lb (6.8 kg) over 6 months. MEASUREMENTS: All measurements were conducted at baseline and 3 and 6 months, except for synovial fluid analysis, which was obtained only at baseline and 6 months. In addition, weight was measured weekly in the E&D group. Physical disability and knee pain were measured by self-report and physical performance was measured using the 6-minute walk and stair climb tasks. Biomechanical testing included kinetic and kinematic analysis of gait and isokinetic strength testing. Synovial fluid was analyzed for levels of total proteoglycan, keratan sulfate, and interleukin-1 beta. RESULTS: Twenty-one of the 24 participants completed the study, with one dropout in the E&D group and two in the E group. The E&D group lost a mean of 18.8 lb (8.5 kg) at 6 months compared with 4.0 lb (1.8 kg) in the E group (P = .01). Significant improvements were noted in both groups in self-reported disability and knee pain intensity and frequency as well as in physical performance measures. However, no statistical differences were found between the two groups at 6 months in knee pain scores or self-reported performance measures of physical function. There was no difference in knee strength between the groups, with both groups showing modest improvements from baseline to 6 months. At 6 months, the E&D group had a significantly greater loading rate (P = .03) and maximum braking force (P = .01) during gait. There were no significant between-group differences in the other biomechanical measures. Synovial fluid samples were obtainable at both baseline and 6 months in eight participants (four per group). The level of keratan sulfate decreased similarly in both groups from an average baseline of 96.8 +/- 37.1 to 71.5 +/- 23 ng/microg total proteoglycan. The level of IL-1 decreased from 25.3 +/- 9.8 at baseline to 8.3 +/- 6.1 pg/mL. The decrease in IL-1 correlated with the change in pain frequency (r = -0.77, P = .043). CONCLUSIONS: Weight loss can be achieved and sustained over a 6-month period in a cohort of older obese persons with osteoarthritis of the knee through a dietary and exercise intervention. Both exercise and combined weight loss and exercise regimens lead to improvements in pain, disability, and performance. Moreover, the trends in the biomechanical data suggest that exercise combined with diet may have an additional benefit in improved gait compared with exercise alone. A larger study is indicated to determine if weight loss provides additional benefits to exercise alone in this patient population.

Contributions of acute bouts of vigorous physical activity to explaining diurnal variations in feeling states in active, middle-aged women.

This study describes diurnal variations in feeling states in 84 women as a function of involvement in physical activity. Women completed feeling state checklists before and after bouts of vigorous physical activity that lasted a minimum of 20 min and on a stratified random-sampling protocol in response to a stimulus from an electronic pager. Participants self-reported the date, the time of day, the stimulus for responding, their current feeling states, and their ongoing activity. A total of 7,295 complete mood and activity reports were recorded in response to pager calls that were further coded into experience samplings that occurred on a nonexercise day, prior to exercise on an exercise day, and following exercise on an exercise day. Multilevel modeling analyses showed that in samplings recorded following exercise on exercise days, positive engagement, revitalization, and tranquility were elevated in comparison with predicted diurnal patterns.