Depressive Symptoms and Physical Performance in the Lifestyle Interventions and Independence for Elders Pilot ( LIFE-P ) Study

OBJECTIVES—To determine whether the presence of high depressive symptoms diminished physical performance benefits after a comprehensive physical activity intervention in older adults. STUDY DESIGN—A post-hoc analysis of data from the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study which was a single blind randomized controlled trial comparing a moderate intensity physical activity intervention (PA) with a successful aging control (SA). SETTING—Multi-center U.S. sites participating in the LIFE-P trial. PARTICIPANTS—LIFE-P trial participants included 424 sedentary, non-institutionalized adults (70–89 years). MEASUREMENTS—Depressive symptoms were assessed by the Centers for Epidemiological Studies Depression Scale (CES-D). Physical performance tests included the Short Physical Performance Battery (SPPB) and 400 meter walk time (400 mw) at baseline, 6 and 12 months. RESULTS—Of the participants, 15.8% had high depressive symptom scores (CES-D ≥ 14). For participants with low depressive symptoms, SPPB scores improved in the PA versus the SA group over 12 months (adjusted score difference: +0.70; p = <0.001 at 6 months and +0.58; p=0.004 at 12 months) while the 400 mw times improved in the PA group at 6 months (adjusted score difference −0.41 min.; p=0.021). For those with high depressive symptoms, a trend toward statistical improvement in the SPPB was observed in the PA versus SA group (adjusted score difference +0.76 (p=0.176) at 6 months and +0.94 (p=0.116) at 12 months). Corresponding Author: Dr. Margaret Matthews, 3010 Farrow Road, Suite #300A, Columbia, SC 29203; voice: 803-434-1214; fax: 803-434-4431; Margaret.Matthews@palmettohealth.org. Conflicts of Interest: All authors have disclosed no evidence of financial or other conflicts of interest other than Dr. Blair who has disclosed receiving guest lecture honoraria, author related royalties from a previous textbook, and participates in grant activities that have been corporate and government funded. Author Contributions: Drs. Matthews, Barry, and Patel were involved in study concept and design, data interpretation, manuscript preparation and critical revision. Dr. Hsu and Mike Walkup served a role in acquisition of data, statistical analysis, manuscript preparation and critical revision. Dr. Steven Blair’s role was PI of one of the clinical centers and participated in original study concept and design of the project, supervised conduct of the LIFE-P trial, and assisted in this manuscript preparation and critical revision. NIH Public Access Author Manuscript J Am Geriatr Soc. Author manuscript; available in PMC 2012 March 1. Published in final edited form as: J Am Geriatr Soc. 2011 March ; 59(3): 495–500. doi:10.1111/j.1532-5415.2011. 03319.x. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript CONCLUSION—The presence of high depressive symptoms did not substantially diminish physical performance benefits realized after a PA intervention in sedentary older adults. INTRODUCTION Depressive symptoms are associated with decline in physical performance in older adults in both cross-sectional and longitudinal epidemiological studies (1–3). A diagnosis of depression has been associated with low physical activity levels in older adults (4, 5) and is considered a risk factor for mobility disability (6). The presence of elevated or high depressive symptoms in the absence of a clinical diagnosis of depression may be associated with the same negative effects on functional ability and health outcomes found in those with a diagnosis of major depression (7). Sedentary older adults, especially those with symptoms of depression, would appear logical target groups for exercise interventions that improve physical performance (8, 9). However, poor adherence rates and self-efficacy in older adults with depression have been reported as potential barriers to the success of exercise interventions (6,10). Whether the presence of high depressive symptoms, independent of such barriers, modifies physical performance benefits resulting from structured exercise interventions is unclear. A relationship between increasing levels of physical activity and decreasing depressive symptoms has been demonstrated independent of physical and psychological health (11, 12). Multiple clinical trials have demonstrated that physical activity may be an effective strategy to reduce depressive symptoms in older adults (13–16). The potential anti-depressive benefits of physical activity further complicate the ability to understand how depressive symptoms influence physical performance outcomes after an exercise intervention. Reduction in depression scores, concomitant with improvements in performance, has largely been demonstrated in exercise trials that have targeted clinically depressed individuals (13, 14, 17). It is less clear whether exercise improves mood in non-depressed individuals (15). In addition, the mechanistic relationship between physical activity and depression is not well understood but may vary by exercise mode, intensity, duration, and baseline depression level (17). Recent findings from the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study found significant improvements in lower extremity physical performance for participants in a physical activity (PA) intervention compared to a successful aging (SA) control (18). Understanding whether the presence of co-morbid factors such as high depressive symptoms influence outcomes from an exercise intervention is relevant to identifying appropriate target groups. Using data from the LIFE-P study (18), the present study examined whether benefits in physical performance outcomes are modified by the presence of high depressive symptoms after implementation of a PA intervention. It was hypothesized that the positive effect of the PA intervention on physical performance would be diminished in those with high depressive symptoms scores. A secondary hypothesis that depression scores would improve in those with high depressive symptoms after a PA intervention is also explored. METHODS Study Design This study is a secondary analysis of data from the LIFE-P trial previously described by investigators (19). Briefly, LIFE-P was a single-blind, multi-center, randomized controlled study contrasting a PA intervention with a SA education control in sedentary older adults, with physical performance outcome measures including the SPPB and 400 mw time proximal to the primary outcome measure of major mobility disability. Here data were Matthews et al. Page 2 J Am Geriatr Soc. Author manuscript; available in PMC 2012 March 1. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript analyzed to examine whether the baseline depressive symptom scores modify physical performance outcomes. Participants Inclusion and exclusion criteria and recruitment are described elsewhere (18, 19). Participants were 424 older adults at risk for lower extremity disability due to low physical activity levels. Eligibility criteria were: (a) age 70–89 years, (b) sedentary lifestyle (<20 min per week spent in structured PA during the past month), (c) ability to walk 400 meters within 15 minutes without sitting or use of an assistive device, and (d) having an SPPB score < 10 (18, 19). Interventions The PA intervention utilized a combination of aerobic, strength, flexibility and balance exercises along three phases. The adoption phase (weeks 1–8) involved an introductory individualized session followed by three 40–60 minute center-based group sessions per week. In the transition phase (weeks 9–24) two center-based exercise sessions per week were combined with home-based endurance/strength/flexibility exercises at least three times per week. The maintenance phase (weeks 25 to end of trial) utilized a home-based intervention along with group-based behavioral counseling sessions (1 time per week for the first 10 weeks), walking (goal of a minimum of 150 minutes per week) and optional one or two group sessions per week. The SA control participants met in small groups weekly for the first 26 weeks, monthly thereafter, and were given a series of sessions on health topics relevant to older adults. At the end of each session, 5 to 10 minutes of upper extremity stretching exercises were provided. Measurements Demographic and clinical variables—Baseline interviews included anthropometric measures, a physical exam, electrocardiogram, a physician evaluation, and a Mini-Mental Status Examination (MMSE) (20). Clinical conditions and medications were assessed using self-reported, physician-diagnosed disease information. PA was self-reported using the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire (21). Depression—Depressive symptoms were assessed using the 20 item Center for Epidemiological Studies Depression (CES-D) scale which measures depressive feelings and behaviors experienced in the past week (22). On this scale (0 to 60), a score of 16 or greater indicates depression. To improve power in this analysis, participants were separated into groups of “low” and “high” depressive symptoms utilizing one standard deviation above the mean scoring. This resulted in a score of 14 or greater representing those with “high” depressive symptoms versus a score of less than 14 denoting “low” depressive symptoms. Physical performance measures—The Short Physical Performance Battery (SPPB) includes a 4 meter self-paced walking speed, balance tests, and chair stand tests. A categorical score in each of the three areas (0–4), and a summary score is determined (0–12) with a higher score indicating better performance (23). A 400 meter walk time (400 mw) involved participants walking 10 laps of a 40-meter course at a comfortable, self-directed pace (19). Time to complete the course was recorded in minutes and seconds. Statistical Analysis—Statistical analyses were performed using SAS software, (SAS Version 9.1, SA