Incident Major Mobility Disability Research Articles

Older adults with clinically relevant depressive symptoms have equal mobility benefit from a chronic physical activity intervention

Approximately 18% of older adults experience mild-to-severe depressive symptoms in the U.S., which in turn can negatively affect their physical and cognitive health. It is widely acknowledged that physical activity has a positive impact on mood and depression and is highly recommended for symptom management across all ages. Little is known, however, about whether elevated depressive symptoms interfere with the potential benefits of chronic exercise on physical outcomes such as mobility improvements in older adults. In this secondary data analysis of the Lifestyle Interventions and Independence for Elders (LIFE) study, we analyzed data from 1545 older adults (mean age = 78.8, 66.7% female) randomized to either a physical activity or health education intervention with an average of 2.2 years of follow-up. We evaluated whether the presence of clinically relevant depressive symptoms (defined as a rescaled score of ≥16 on the Center for Epidemiological Studies-Depression [CES-D]-11 scale) moderated the effect of a chronic physical activity intervention on incident major mobility disability (MMD), objectively measured as the ability to walk 400 m and assessed every 6 months. There were significant main effects of both the physical activity intervention (p = 0.018) and clinically relevant depression (p < 0.001) on incident MMD, but we found no evidence of moderation by depression status (interaction p-value = 0.989). Our findings suggest older adults with clinically relevant depressive symptoms derive similar benefits from participating in a comprehensive physical activity intervention in terms of reduced risk of mobility disability. These results support the inclusion of older adults with depressive symptoms in behavior-based clinical trials.

TESTING THE MODERATING EFFECTS OF DEPRESSIVE SYMPTOMS ON A PHYSICAL ACTIVITY INTERVENTION

Abstract Depressive symptoms affect the physical and cognitive health of approximately 20% of older adults. These symptoms have strong, bidirectional ties with physical activity levels and mobility disability. Physical activity has a positive impact on mood and depression and is highly recommended for symptom management across all ages. However, it’s unclear whether elevated depressive symptoms interfere with potential benefits that physical activity has on other health outcomes like mobility loss. The Lifestyle Interventions and Independence for Elders (LIFE) Study randomized over 1,500 older adults (aged 70+) to either a physical activity (intervention) or successful aging (control) program with an average of 2.2 years of follow-up. Our analysis used Cox proportional hazards models to evaluate whether elevated depressive symptoms (measured using the Center for Epidemiological Studies-Depression (CESD)-11 scale with a cutoff score of 16/22 points) moderated the relationship between intervention status and the primary outcome (incident major mobility disability, objectively measured as the ability to walk 400 meters). In a secondary analysis of 1,534 older adults (Mage = 78.8, 66.7% female), we confirmed significant main effects of both the physical activity intervention and elevated depressive symptoms on incident major mobility disability but found no evidence of moderation (interaction p-value=0.989). Results indicate that the benefits of the intervention were comparable between those with and without significant depressive symptoms at baseline, supporting the inclusion of individuals with depression in clinical trials. In addition to potential symptom relief, promoting physical activity in older adults with depression is important for protecting against mobility loss.

The Impact of ApoE e4 Allele in the Effects of Physical Activity Interventions on Major Mobility Disability Incidence

The apolipoprotein E (ApoE) e4 polymorphism is traditionally linked to increased rates of cognitive impairments and Alzheimer’s Disease. Recently, however, studies have connected ApoE e4 to self-reported mobility disability in those without cognitive impairment. We aimed to estimate the extent to which ApoE status is associated with incident major mobility disability (MMD) and whether it modifies the known beneficial effects of physical activity on incident MMD. Data were from 1,372 participants 70+ years old at risk for mobility impairments, enrolled in The LIFE Study. Participants were randomized to a structured physical activity (PA) or a health education program. The primary outcome was MMD, defined as the inability to walk 400 meters and measured every 6 months for an average follow-up period of 2.6 years. We used proportional hazards regression to examine the main effect of ApoE allele status and interaction with intervention group on MMD incidence. Cumulative MMD incident rates were similar in ApoE-e2 (31.46%), ApoE e3 (33.41%), and ApoE-e4 (33.33%) carriers. Compared to the common ApoE-e3, MMD risk was similar in ApoE-e2 (hazard ratio [HR], 0.945 [95%CI, 0.70-1.27], P=0.71) and ApoE-e4 carriers ([HR], 1.187 [95%CI, 0.95-1.48], P=0.41). Additionally, ApoE carrier status did not modify the positive effect that a PA intervention had on MMD risk (interaction p-value > 0.20). These results suggest that ApoE carrier status is not associated with incident mobility disability. ApoE carrier status does not impact the effect a structured PA program has on reducing the risk of MMD in older adults.

Impact of Baseline Fatigue on a Physical Activity Intervention to Prevent Mobility Disability.

Our aim was to examine the impacts of baseline fatigue on the effectiveness of a physical activity (PA) intervention to prevent major mobility disability (MMD) and persistent major mobility disability (PMMD) in participants from the Lifestyle Interventions and Independence for Elders (LIFE) study. Prospective cohort of individuals aged 65 years or older undergoing structured PA intervention or health education (HE) for a mean of 2.6 years. LIFE was a multicenter eight-site randomized trial that compared the efficacy of a structured PA intervention with an HE program in reducing the incidence of MMD. Study participants (N = 1591) at baseline were 78.9 ± 5.2 years of age, with low PA and at risk for mobility impairment. Self-reported fatigue was assessed using the modified trait version of the Exercise-Induced Feelings Inventory, a six-question scale rating energy levels in the past week. Responses ranged from 0 (none of the time) to 5 (all of the time). Total score was calculated by averaging across questions; baseline fatigue was based on the median split: 2 or higher = more fatigue (N = 856) and lower than 2 = less fatigue (N = 735). Participants performed a usual-paced 400-m walk every 6 months. We defined incident MMD as the inability to walk 400-m at follow-up visits; PMMD was defined as two consecutive walk failures. Cox proportional hazard models quantified the risk of MMD and PMMD in PA vs HE stratified by baseline fatigue adjusted for covariates. Among those with higher baseline fatigue, PA participants had a 29% and 40% lower risk of MMD and PMMD, respectively, over the trial compared with HE (hazard ratio [HR] for MMD = .71; 95% confidence interval [CI] = .57-.90; P = .004) and PMMD (HR = .60; 95% CI = .44-.82; P = .001). For those with lower baseline fatigue, no group differences in MMD (P = .36) or PMMD (P = .82) were found. Results of baseline fatigue by intervention interaction was MMD (P = .18) and PMMD (P = .05). A long-term moderate intensity PA intervention was particularly effective at preserving mobility in older adults with higher levels of baseline fatigue. J Am Geriatr Soc 68:619-624, 2020.

RATINGS OF PERCEIVED EXERTION: PREDICTING MOBILITY DISABILITY AND RESPONSE TO PHYSICAL ACTIVITY IN OLDER ADULTS

Ratings of perceived exertion (RPE) during exercise are linked to several physiological indices and are often elevated in older adults. This study evaluated the association between RPE of walking and incident major mobility disability (MMD) as well as response to a physical activity (PA) program. Older adults (n=1633) at-risk for mobility impairment were randomized to a structured PA or health education (HE) program. During a 400m walk, participants rated exertion as “none”, “light”, “somewhat hard” or “hard”. An MMD event was defined as the inability to complete the 400m walk. Transitions between RPE states and an MMD event—when RPE was not collected— were assessed over the follow-up (every 6 months for an average of 2.6 years). Participants rating their exertion as “hard” at baseline 400m walk had nearly 3-fold higher risk of MMD compared with those rating as “light” (HR: 2.61, 95%CI: 2.19-3.11). During follow-up, the PA group was 25% more likely to transition from “light” to “hard” RPE (1.25, 1.05-1.49), but was 27% (0.73, 0.55 – 0.97) less likely to transition from a “hard” RPE to MMD than the HE group. Additionally, the PA group was more likely to transition from an MMD event to a “hard” RPE (2.09, 1.38-3.17) than the HE group (i.e. recovery). Older adults rating “hard” effort during a standardized walk test were at increased risk of MMD. A structured PA program increased transition from light to hard effort, which may reflect greater capacity to perform the test and increased recovery from an MMD event.

Association of Fish Oil and Physical Activity on Mobility Disability in Older Adults.

This study aimed to examine whether long-term fish oil (FO) supplementation is associated with a lower risk of mobility disability and enhances benefits of physical activity (PA). A total of 1635 sedentary adults age 70 to 89 yr from the Lifestyle Interventions and Independence for Elders single-blinded randomized, multicenter clinical trial, which compared a structured PA program to a health education program. Primary outcome was incident major mobility disability (MMD), defined by loss of ability to walk 400 m, measured every 6 months for an average of 2.6 yr. Secondary outcomes included persistent mobility disability, Short Physical Performance Battery, 400-m walk speed, and grip strength. A third of participants reported using FO at baseline (456 (28%); mean age, 78.5 yr; 70.5% women). MMD was experienced by 131 participants (28.7%) in the FO group and 405 (34.4%) participants in the nonuser group. After adjusting for confounders, FO supplementation was associated with a lower risk (HR, 0.78; 95% confidence interval (CI), 0.64-0.96) of incident MMD. However, there was no interaction (P = 0.19) between FO supplementation and PA intervention for MMD. For the secondary outcome of persistent mobility disability, the intervention association differed by supplementation (P = 0.002) with PA intervention associations of (HR, 1.36; 95% CI, 0.83-2.23) for users and (HR, 0.61; 95% CI, 0.46-0.81) for nonusers. Changes in physical performance outcomes were not modified by baseline FO supplementation or combination with PA. FO supplementation was associated with a lower risk of MMD in low to moderate functioning older adults. However, supplementation did not enhance the benefit of PA on risk of mobility disability. These results are hypothesis generating and need to be confirmed in randomized trials.

A Case for Promoting Movement Medicine: Preventing Disability in the LIFE Randomized Controlled Trial.

The movement profile of older adults with compromised function is unknown, as is the relationship between these profiles and the development of major mobility disability (MMD)-a critical clinical outcome. We first describe the dimensions of movement in older adults with compromised function and then examine whether these dimensions predict the onset of MMD. Older adults at risk for MMD (N = 1,022, mean age = 78.7 years) were randomized to receive a structured physical activity intervention or health education control. We assessed MMD in 6-month intervals (average follow-up of 2.2 years until incident MMD), with activity assessed at baseline, 6-, 12- and 24-month follow-up via accelerometry. A principal components analysis of 11 accelerometer-derived metrics yielded three components representing lifestyle movement (LM), extended bouts of moderate-to-vigorous physical activity (MVPA), and stationary body posture. LM accounted for the greatest proportion of variance in movement (53%). Within health education, both baseline LM (HR = 0.74; 95% CI 0.62 to 0.88) and moderate-to-vigorous physical activity (HR = 0.69; 95% CI 0.54 to 0.87) were associated with MMD, whereas only LM was associated with MMD within physical activity (HR = 0.74; 95% CI 0.61 to 0.89). There were similar nonlinear relationships present for LM in both physical activity and health education (p < .04), whereby risk for MMD was lower among individuals with higher levels of LM. Both LM and moderate-to-vigorous physical activity should be central in treatment regimens for older adults at risk for MMD. clinicaltrials.gov Identifier NCT01072500.

Effect of Physical Activity on Frailty: Secondary Analysis of a Randomized Controlled Trial.

Limited evidence suggests that physical activity may prevent frailty and associated negative outcomes in older adults. Definitive data from large long-term randomized trials are lacking. To determine whether a long-term, structured, moderate-intensity physical activity program is associated with a lower risk for frailty and whether frailty status alters the effect of physical activity on the reduction in major mobility disability (MMD) risk. Multicenter, single-blind, randomized trial. 8 centers in the United States. 1635 community-dwelling adults, aged 70 to 89 years, with functional limitations. A structured, moderate-intensity physical activity program incorporating aerobic, resistance, and flexibility activities or a health education program consisting of workshops and stretching exercises. Frailty, as defined by the SOF (Study of Osteoporotic Fractures) index, at baseline and 6, 12, and 24 months, and MMD, defined as the inability to walk 400 m, for up to 3.5 years. Over 24 months of follow-up, the risk for frailty (n= 1623) was not statistically significantly different in the physical activity versus the health education group (adjusted prevalence difference, -0.021 [95% CI, -0.049 to 0.007]). Among the 3 criteria of the SOF index, the physical activity intervention was associated with improvement in the inability to rise from a chair (adjusted prevalence difference, -0.050 [CI, -0.081 to -0.020]). Baseline frailty status did not modify the effect of physical activity on reducing incident MMD (P for interaction= 0.91). Frailty status was neither an entry criterion nor a randomization stratum. A structured, moderate-intensity physical activity program was not associated with a reduced risk for frailty over 2 years among sedentary, community-dwelling older adults. The beneficial effect of physical activity on the incidence of MMD did not differ between frail and nonfrail participants. National Institute on Aging, National Institutes of Health.

Device-Measured Physical Activity As a Predictor of Disability in Mobility-Limited Older Adults.

To examine associations between objectively measured physical activity (PA) and incidence of major mobility disability (MMD) and persistent MMD (PMMD) in older adults in the Lifestyle Interventions and Independence for Elders (LIFE) Study. Prospective cohort of individuals aged 65 and older undergoing structured PA intervention or health education. The LIFE Study was a multicenter (eight sites) randomized controlled trial designed to compare the efficacy of a long-term structured PA intervention with that of a health education (HE) program in reducing the incidence of MMD in mobility-limited older adults. LIFE Study participants (n = 1,590) had a mean age±standard deviation of 78.9 ± 5.2, low levels of PA, and measured mobility-relevant functional impairment at baseline. Activity data were collected using hip-worn 7-day accelerometers at baseline and 6, 12, and 24 months after randomization to test for associations with incident MMD and PMMD (≥2 consecutive instances of MMD). At baseline, every 30 minutes spent being sedentary (<100 accelerometry counts per minute) was associated with higher rate of subsequent MMD (10%) and PMMD (11%) events. Every 500 steps taken was associated with lower rate of MMD (15%) and PMMD (18%). Similar associations were observed when fitting accelerometry-based PA as a time-dependent variable. Accelerometry-based PA levels were strongly associated with MMD and PMMD events in older adults with limited mobility. These results support the importance of daily PA and lower amounts of sedentary time levels in this population and suggest that accelerometry may be a useful tool for assessing risk of mobility disability.

The MAT-sf: identifying risk for major mobility disability.

The assessment of mobility is essential to both aging research and clinical geriatric practice. A newly developed self-report measure of mobility, the mobility assessment tool-short form (MAT-sf), uses video animations as an innovative method to improve measurement accuracy/precision. The primary aim of the current study was to evaluate whether MAT-sf scores can be used to identify risk for major mobility disability (MMD). This article is based on data collected from the Lifestyle Interventions and Independence for Elders study and involved 1,574 older adults between the ages of 70-89. The MAT-sf was administered at baseline; MMD, operationalized as failure to complete the 400-m walk ≤ 15 minutes, was evaluated at 6-month intervals across a period of 42 months. The outcome of interest was the first occurrence of MMD or incident MMD. After controlling for age, sex, clinic site, and treatment arm, baseline MAT-sf scores were found to be effective in identifying risk for MMD (p < .0001). Partitioning the MAT-sf into four groups revealed that persons with scores <40, 40-49, 50-59, and 60+ had failure rates across 42 months of follow-up of 66%, 52%, 35%, and 22%, respectively. The MAT-sf is a quick and efficient way of identifying older adults at risk for MMD. It could be used to clinically identify older adults that are in need of intervention for MMD and provides a simple means for monitoring the status of patients' mobility, an important dimension of functional health.

Effect of structured physical activity on prevention of major mobility disability in older adults: the LIFE study randomized clinical trial.

In older adults reduced mobility is common and is an independent risk factor for morbidity, hospitalization, disability, and mortality. Limited evidence suggests that physical activity may help prevent mobility disability; however, there are no definitive clinical trials examining whether physical activity prevents or delays mobility disability. To test the hypothesis that a long-term structured physical activity program is more effective than a health education program (also referred to as a successful aging program) in reducing the risk of major mobility disability. The Lifestyle Interventions and Independence for Elders (LIFE) study was a multicenter, randomized trial that enrolled participants between February 2010 and December 2011, who participated for an average of 2.6 years. Follow-up ended in December 2013. Outcome assessors were blinded to the intervention assignment. Participants were recruited from urban, suburban, and rural communities at 8 centers throughout the United States. We randomized a volunteer sample of 1635 sedentary men and women aged 70 to 89 years who had physical limitations, defined as a score on the Short Physical Performance Battery of 9 or below, but were able to walk 400 m. Participants were randomized to a structured, moderate-intensity physical activity program (n = 818) conducted in a center (twice/wk) and at home (3-4 times/wk) that included aerobic, resistance, and flexibility training activities or to a health education program (n = 817) consisting of workshops on topics relevant to older adults and upper extremity stretching exercises. The primary outcome was major mobility disability objectively defined by loss of ability to walk 400 m. Incident major mobility disability occurred in 30.1% (246 participants) of the physical activity group and 35.5% (290 participants) of the health education group (hazard ratio [HR], 0.82 [95% CI, 0.69-0.98], P = .03).Persistent mobility disability was experienced by 120 participants (14.7%) in the physical activity group and 162 participants (19.8%) in the health education group (HR, 0.72 [95% CI, 0.57-0.91]; P = .006). Serious adverse events were reported by 404 participants (49.4%) in the physical activity group and 373 participants (45.7%) in the health education group (risk ratio, 1.08 [95% CI, 0.98-1.20]). A structured, moderate-intensity physical activity program compared with a health education program reduced major mobility disability over 2.6 years among older adults at risk for disability. These findings suggest mobility benefit from such a program in vulnerable older adults. clinicaltrials.gov Identifier: NCT01072500.

The lifestyle interventions and independence for elders (LIFE) pilot study: Design and methods

The LIFE study is a multicenter pilot for a proposed full scale, two-arm randomized controlled trial that will contrast the effect of a physical activity intervention with a successful aging education program on the occurrence of incident major mobility disability (the inability to complete a 400 m walk) or death in at-risk sedentary older adults. Four hundred older adults from 4 clinical sites will be recruited for this purpose. All participants will be followed for at least 1-year; however, we will continue to follow all participants until the final randomized individual has reached the 1-year mark. This will enable us to acquire additional information about maintenance. Additional outcomes will include lower extremity physical performance as well as gait speed over 4 m and 400 m. These latter measures will provide data on the efficacy of the intervention on intermediate endpoints linked to the primary outcome of interest. The goals of the pilot study are to (a) estimate the sample size needed for a full scale trial, (b) examine the consistency of the effects of the physical activity intervention on several continuous measures of physical function, (c) assess the feasibility of recruitment, (d) evaluate study adherence and retention, (d) evaluate the efficacy of a stepped care approach for managing intercurrent illness in this at-risk population, and (e) develop a comprehensive system for monitoring and ensuring participant safety. Other goals of this pilot phase include assessments of health-related quality of life and cost-effectiveness.