Leisure-time physical activity and leukocyte telomere length among older women

BACKGROUND

Shortened leukocyte telomere length (LTL), a purported marker of cellular aging, is associated with morbidity and mortality. However, the association of physical activity, a modifiable lifestyle behavior, with LTL has not been adequately studied among older adults.

METHODS

In this cross-sectional study, we examined associations of various intensity levels of leisure-time physical activity with LTL among 1476 older white and African American women from the Women's Health Initiative Objective Physical Activity and Cardiovascular Health study. Self-reported physical activity was assessed by questionnaire, and LTL was measured by Southern blot. The association between physical activity and LTL was evaluated using multiple linear regression models adjusted for demographic characteristics, lifestyle behaviors, and health-related variables.

RESULTS

Women were on average aged 79.2 (standard deviation 6.7) years old. In the final model adjusted for age, race/ethnicity, education, marital status, smoking, alcohol, body mass index, a history of chronic diseases, and hormone therapy use, LTL was on average 110 (95% confidence interval, 20-190) base pairs longer among women in the highest (≥17.00MET-hours/week) compared with the lowest (<1.25MET-hours/week) level of total leisure-time physical activity (P for trend=0.02). Higher levels of moderate-to-vigorous physical activity (P for trend=0.04) and faster walking speed (P for trend=0.03) were also associated with longer LTL in the fully-adjusted models.

CONCLUSION

Older women participating in greater amounts of total leisure-time physical activity and moderate-to-vigorous physical activity had longer LTL.

Evaluating Walking Intensity with Hip-Worn Accelerometers in Elders

PURPOSE

Accelerometer activity counts are used to objectively categorize physical activity levels. We examined the association between accelerometer activity counts and metabolic effort in older adults.

METHODS

Forty-five older adults (76.3 ± 5.1 yr) completed a 400-m walk at both a usual and a rapid pace. A portable metabolic unit measured pulmonary gas exchange, whereas a hip-worn accelerometer measured activity counts. Participants were categorized as either a "slow walker" or a "fast walker" based on the threshold of 1.0 m·s during usual-pace walking.

RESULTS

Activity counts during rapid (r = 0.62, P < 0.01) but not usual-pace (r = 0.24, P = 0.11) walking were significantly associated with METs. Slow walkers attained only half the activity counts of fast walkers during each walk condition (P < 0.01), while at the same time achieving between 82% and 90% of their MET level.

CONCLUSION

Accelerometers may misclassify the activity level of functionally impaired older adults with slow walking speed.

Dose of physical activity, physical functioning and disability risk in mobility-limited older adults: Results from the LIFE study randomized trial

Understanding the minimal dose of physical activity required to achieve improvement in physical functioning and reductions in disability risk is necessary to inform public health recommendations. To examine the effect of physical activity dose on changes in physical functioning and the onset of major mobility disability in The Lifestyle Interventions and Independence for Elders (LIFE) Study. We conducted a multicenter single masked randomized controlled trial that enrolled participants in 2010 and 2011 and followed them for an average of 2.6 years. 1,635 sedentary men and women aged 70-89 years who had functional limitations were randomized to a structured moderate intensity walking, resistance, and flexibility physical activity program or a health education program. Physical activity dose was assessed by 7-day accelerometry and self-report at baseline and 24 months. Outcomes included the 400 m walk gait speed, the Short Physical Performance Battery (SPPB), assessed at baseline, 6, 12, and 24 months, and onset of major mobility disability (objectively defined by loss of ability to walk 400 m in 15 min). When the physical activity arm or the entire sample were stratified by change in physical activity from baseline to 24 months, there was a dose-dependent increase in the change in gait speed and SPPB from baseline at 6, 12, and 24 months. In addition, the magnitude of change in physical activity over 24 months was related to the reduction in the onset of major mobility disability (overall P < 0.001) (highest versus the lowest quartile of physical activity change HR 0.23 ((95% CI:0.10-0.52) P = 0.001) in the physical activity arm. We observed a dose-dependent effect of objectively monitored physical activity on physical functioning and onset of major mobility disability. Relatively small increases (> 48 minutes per week) in regular physical activity participation had significant and clinically meaningful effects on these outcomes.

TRIAL REGISTRATION

ClinicalsTrials.gov NCT00116194.

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

OBJECTIVES

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.

DESIGN

Prospective cohort of individuals aged 65 and older undergoing structured PA intervention or health education.

SETTING

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.

PARTICIPANTS

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.

MEASUREMENTS

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).

RESULTS

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.

CONCLUSION

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.

Association Between Structured Physical Activity and Sedentary Time in Older Adults

This post hoc exploratory analysis of Lifestyle Interventions and Independence for Elders (LIFE) trial data examines the association between the trial’s physical activity intervention and sedentary time in older adults.

Hospitalizations During a Physical Activity Intervention in Older Adults at Risk of Mobility Disability: Analyses from the Lifestyle Interventions and Independence for Elders Randomized Clinical Trial

OBJECTIVES

To determine whether moderate-intensity physical activity (PA) and health education (HE) are differentially associated with categories of hospitalizations or subgroups of participants.

DESIGN

Multicenter randomized controlled trial in which participants were randomized to a PA or HE program for an average of 2.6 years.

SETTING

Eight field centers.

PARTICIPANTS

Sedentary men and women aged 70-89 with lower extremity physical limitations but able to walk 400-m in 15 minutes or less (N = 1,635).

INTERVENTIONS

Structured, moderate-intensity PA (n =  818) at a center (2×/wk) and at home (3-4×/wk) that included aerobic, strength, balance, and flexibility training or HE (n =  817) of educational workshops and upper extremity stretching exercises.

MEASUREMENTS

All-cause inpatient hospitalizations ascertained at 6-month intervals.

RESULTS

There were 1,458 hospitalizations (49.1% of PA, 44.4% of HE; risk difference = 4.68%, 95% confidence interval (CI) = -0.18-9.54; hazard ratio (HR) = 1.16, 95% CI = 1.00-1.34). The intervention effect on incident hospitalization did not differ according to race, sex, Short Physical Performance Battery score, age, or history of cardiovascular disease or diabetes mellitus. PA was associated with higher rates of hospitalization in the middle baseline gait speed category, than HE (<0.8 m/s: HR = 0.93, 95% CI = 0.76-1.14; 0.8-1.0 m/s: HR = 1.54, 95% CI = 1.23-1.94; >1.0 m/s: HR = 1.05, 95% CI = 0.67-1.65; interaction P = .005).

CONCLUSION

A PA program in older adults at risk for mobility disability did not lead to a different risk of specific types of hospitalizations than a HE program overall. Baseline gait speed may be a marker for risk of hospitalization during a PA intervention, because individuals with moderate baseline gait speed in the PA group had slightly higher rates of hospitalization than those in the HE group.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01072500.

Prognostic Value of Braden Activity Subscale for Mobility Status in Hospitalized Older Adults

OBJECTIVE

To evaluate the predictive value of the Activity subscale of the Braden Scale for Predicting Pressure Sore Risk in assessing mobility impairment and recovery among hospitalized older adults.

DESIGN

Retrospective cohort study.

SETTING

UF Health Shands Hospital, University of Florida, Gainesville, Florida.

PATIENTS

19,769 older adults (≥65 years) hospitalized between January 2009 and April 2014.

MEASUREMENTS

Incident mobility impairment and recovery were assessed with the Braden Activity subscale (BAS) score that nurses use to grade patients at every shift change (~3 times/d). Posthospital mortality rate and discharge disposition were used to assess the prognostic value of the BAS.

RESULTS

Of the 10,717 study patients observed "walking frequently" at admission, 2218 (20.7%) developed incident mobility impairment. Of the other 9052 study patients, who were impaired at admission, 4734 (52.3%) recovered to a state of walking occasionally or frequently. Older adults who developed mobility impairment during hospitalization had an odds of death higher than that of those who remained mobile (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.08- 1.39). This effect predominately occurred within the first 6 follow-up months. Older adults who recovered from mobility impairment had an odds of death lower than that of those who did not recover mobility in the hospital (OR, 0.54; 95% CI, 0.49-0.59). This effect was slightly stronger within the first 6 months after hospitalization.

CONCLUSIONS

Nurses' BAS assessment of mobility status during hospitalization provides substantial prognostic value in hospitalized older adults. The BAS could be an efficient and valuable source of information about mobility status for targeting posthospital care of older adults. Journal of Hospital Medicine 2017;12:396-401.

Wearable technology to reduce sedentary behavior and CVD risk in older adults: design of a randomized controlled trial

Persons aged over 65 years account for over the vast majority of healthcare expenditures and deaths attributable to cardiovascular disease (CVD). Accordingly, reducing CVD risk among older adults is an important public health priority. Structured physical activity (i.e. exercise) is a well-documented method of decreasing CVD risk, but recent large-scale trials suggest that exercise alone is insufficient to reduce CVD events in high-risk populations of older adults. Thus adjuvant strategies appear necessary to reduce CVD risk. Accumulating evidence indicates that prolonged sedentary behavior (e.g. sitting) has detrimental health effects that are independent of engagement in recommended levels of moderate-intensity exercise. Yet clinical trials in this area are lacking. We hypothesize that exercise, when combined with a novel technology based intervention specifically designed to reduce sedentary behavior will reduce CVD risk among sedentary older adults. The purpose of this study is to evaluate the feasibility and efficacy of combining a traditional, structured exercise intervention with an innovative intervention designed to decrease sedentary behavior and increase non-exercise physical activity (NEPA). This study will provide us with critical data necessary to design and implement a full-scale trial to test our central hypothesis. Participants aged ≥60 years with moderate to high risk of coronary heart disease (CHD) events are randomly assigned to either the exercise and technology intervention (EX+NEPA) or exercise alone (EX) groups. Study dependent outcomes include changes in 1) daily activity patterns, 2) blood pressure, 3) exercise capacity, 4) waist circumference, and 5) circulating indices of cardiovascular function. This study will provide critical information for designing a fully-powered clinical trial, which could have health implications for the ever increasing population of older adults.

Transition Icons for Time-Series Visualization and Exploratory Analysis

The modern healthcare landscape has seen the rapid emergence of techniques and devices that temporally monitor and record physiological signals. The prevalence of time-series data within the healthcare field necessitates the development of methods that can analyze the data in order to draw meaningful conclusions. Time-series behavior is notoriously difficult to intuitively understand due to its intrinsic high-dimensionality, which is compounded in the case of analyzing groups of time series collected from different patients. Our framework, which we call transition icons, renders common patterns in a visual format useful for understanding the shared behavior within groups of time series. Transition icons are adept at detecting and displaying subtle differences and similarities, e.g., between measurements taken from patients receiving different treatment strategies or stratified by demographics. We introduce various methods that collectively allow for exploratory analysis of groups of time series, while being free of distribution assumptions and including simple heuristics for parameter determination. Our technique extracts discrete transition patterns from symbolic aggregate approXimation representations, and compiles transition frequencies into a bag of patterns constructed for each group. These transition frequencies are normalized and aligned in icon form to intuitively display the underlying patterns. We demonstrate the transition icon technique for two time-series datasets-postoperative pain scores, and hip-worn accelerometer activity counts. We believe transition icons can be an important tool for researchers approaching time-series data, as they give rich and intuitive information about collective time-series behaviors.

Effect of Physical Activity on Self-Reported Disability in Older Adults: Results from the LIFE Study

BACKGROUND/OBJECTIVES

To test the hypothesis that a long-term structured, moderate intensity physical activity (PA) program is more effective than a health education (HE) program in reducing the risk of s elf-reported dependency and disability in basic activities of daily living (BADLs), disability in instrumental ADLs (IADL), and mobility disability.

DESIGN

The Lifestyle Interventions and Independence for Elders (LIFE) study was a multicenter, single-blinded randomized trial.

SETTING

University-based research clinic.

PARTICIPANTS

Thousand six hundred and thirty five sedentary men and women aged 70-89 years, who had functional limitations, defined as a score ≤9 on the Short Physical Performance Battery.

INTERVENTION

Participants were randomized to a structured, moderate intensity PA program (n = 818) that included aerobic, resistance, and flexibility exercises or to a HE program (n = 817).

MEASUREMENTS

All outcomes were derived by self-report using periodic interviews that asked about the degree of difficulty and receipt of help during the past month. Dependency was defined as "receiving assistance" or "unable" to do ≥1 activities. Disability was defined as having "a lot of difficulty" or "unable" doing ≥1 activities. Severe disability was defined as reporting difficulty or being unable to perform ≥3 activities.

RESULTS

Over an average follow-up of 2.6 years, the cumulative incidence of BADL dependency was 15.2% among PA and 15.1% among HE participants (HR = 1.0, 95% CI = 0.78-0.1.3). Intervention groups had similar rates of incident BADL disability, IADL disability and reported mobility disability. Reporting severe mobility disability (HR = 0.78, 95% CI = 0.64-0.96) and ratings of difficulty on mobility tasks were reduced in the PA group.

CONCLUSION

A structured physical activity intervention reduces reported severe mobility disability and difficulty on mobility tasks, but not BADL and IADL disability in older adults with functional limitations.

The effect of intervening hospitalizations on the benefit of structured physical activity in promoting independent mobility among community-living older persons: secondary analysis of a randomized controlled trial

BACKGROUND

Among older persons, disability is often precipitated by intervening illnesses and injuries leading to hospitalization. In the Lifestyle Interventions and Independence for Elders (LIFE) Study, a structured moderate-intensity physical activity program, compared with a health education program, was shown to significantly reduce the amount of time spent with major mobility disability (MMD) over the course of 3.5 years. We aimed to determine whether the benefit of the physical activity program in promoting independent mobility was diminished in the setting of intervening hospitalizations.

METHODS

We analyzed data from a single-blinded, parallel group randomized trial (ClinicalTrials.gov: NCT01072500). In this trial, 1635 sedentary persons, aged 70-89 years, who had functional limitations but were able to walk 400 m, were randomized from eight US centers between February 2010 and December 2013: 818 to physical activity (800 received intervention) and 817 to health education (805 received intervention). Intervening hospitalizations and MMD, defined as the inability to walk 400 m, were assessed every 6 months for up to 3.5 years.

RESULTS

For both the physical activity and health education groups, intervening hospitalizations were strongly associated with the initial onset of MMD and inversely associated with recovery from MMD, defined as a transition from initial MMD onset to no MMD. The benefit of the physical activity intervention did not differ significantly based on hospital exposure. For onset of MMD, the hazard ratios (HR) were 0.79 (95% confidence interval [CI] 0.58-1.1) and 0.77 (0.62-0.95) in the presence and absence of intervening hospitalizations, respectively (P-interaction, 0.903). For recovery of MMD, the magnitude of effect was modestly greater among participants who were hospitalized (HR 1.5, 95% CI 0.71-3.0) than in those who were not hospitalized (HR 1.2, 95% CI 0.88-1.7), but this difference did not achieve statistical significance (P-interaction, 0.670).

CONCLUSIONS

Intervening hospitalizations had strong deleterious effects on the onset of MMD and recovery from MMD, but did not diminish the beneficial effect of the LIFE physical activity intervention in promoting independent mobility. To achieve sustained benefits over time, structured physical activity programs should be designed to accommodate acute illnesses and injuries leading to hospitalizations given their high frequency in older persons with functional limitations.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01072500 .

Effect of Physical Activity versus Health Education on Physical Function, Grip Strength and Mobility

BACKGROUND

Physical activity (PA) reduces the rate of mobility disability, compared with health education (HE), in at risk older adults. It is important to understand aspects of performance contributing to this benefit.

OBJECTIVE

To evaluate intervention effects on tertiary physical performance outcomes.

DESIGN

The Lifestyle Interventions and Independence for Elders (LIFE) was a multi-centered, single-blind randomized trial of older adults.

SETTING

Eight field centers throughout the United States.

PARTICIPANTS

1635 adults aged 78.9 ± 5.2 years, 67.2% women at risk for mobility disability (Short Physical Performance Battery [SPPB] <10).

INTERVENTIONS

Moderate PA including walking, resistance and balance training compared with HE consisting of topics relevant to older adults.

OUTCOMES

Grip strength, SPPB score and its components (balance, 4 m gait speed, and chair-stands), as well as 400 m walking speed.

RESULTS

Total SPPB score was higher in PA versus HE across all follow-up times (overall P = .04) as was the chair-stand component (overall P < .001). No intervention effects were observed for balance (overall P = .12), 4 m gait speed (overall P = .78), or grip strength (overall P = .62). However, 400 m walking speed was faster in PA versus HE group (overall P =<.001). In separate models, 29% of the rate reduction of major mobility disability in the PA versus HE group was explained by change in SPPB score, while 39% was explained by change in the chair stand component.

CONCLUSION

Lower extremity performance (SPPB) was significantly higher in the PA compared with HE group. Changes in chair-stand score explained a considerable portion of the effect of PA on the reduction of major mobility disability-consistent with the idea that preserving muscle strength/power may be important for the prevention of major mobility disability.

The Need for Standardized Assessment of Muscle Quality in Skeletal Muscle Function Deficit and Other Aging-Related Muscle Dysfunctions: A Symposium Report

A growing body of scientific literature suggests that not only changes in skeletal muscle mass, but also other factors underpinning muscle quality, play a role in the decline in skeletal muscle function and impaired mobility associated with aging. A symposium on muscle quality and the need for standardized assessment was held on April 28, 2016 at the International Conference on Frailty and Sarcopenia Research in Philadelphia, Pennsylvania. The purpose of this symposium was to provide a venue for basic science and clinical researchers and expert clinicians to discuss muscle quality in the context of skeletal muscle function deficit and other aging-related muscle dysfunctions. The present article provides an expanded introduction concerning the emerging definitions of muscle quality and a potential framework for scientific inquiry within the field. Changes in muscle tissue composition, based on excessive levels of inter- and intra-muscular adipose tissue and intramyocellular lipids, have been found to adversely impact metabolism and peak force generation. However, methods to easily and rapidly assess muscle tissue composition in multiple clinical settings and with minimal patient burden are needed. Diagnostic ultrasound and other assessment methods continue to be developed for characterizing muscle pathology, and enhanced sonography using sensors to provide user feedback and improve reliability is currently the subject of ongoing investigation and development. In addition, measures of relative muscle force such as specific force or grip strength adjusted for body size have been proposed as methods to assess changes in muscle quality. Furthermore, performance-based assessments of muscle power via timed tests of function and body size estimates, are associated with lower extremity muscle strength may be responsive to age-related changes in muscle quality. Future aims include reaching consensus on the definition and standardized assessments of muscle quality, and providing recommendations to address critical clinical and technology research gaps within the field.

Systemic inflammation, body composition, and physical performance in old community-dwellers

BACKGROUND

Chronic inflammation, changes in body composition, and declining physical function are hallmarks of the ageing process. The aim of the present study was to provide a preliminary characterisation of the relationship among these age-related phenomena via multivariate modelling.

METHODS

Thirty-five old adults (OAs) and 17 young adults (YAs) were enrolled. The volume of skeletal muscle, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) of the thigh was quantified by three-dimensional magnetic resonance imaging. Muscle strength was measured by knee extension strength testing. In OAs, physical performance was further assessed via the Short Physical Performance Battery (SPPB). Multi-block partial least squares-discriminant analysis (PLS-DA) was employed to explore the relationship among inflammatory profiles and functional and imaging parameters. Double cross-validation procedures were used to validate the predictive ability of the PLS-DA model.

RESULTS

The optimal complexity of the PLS-DA model was found to be two latent variables. The proportion of correct classification was 92.3% in calibration (94.1% in YAs and 91.4% in OAs), 84.6% in internal validation (95.3% in YAs and 78.5% in OAs), and 82.6% in external validation (94% in YAs and 76.9% in OAs). Relative to YAs, OAs were characterised by smaller muscle volume, greater IMAT volume, lower muscle strength, and higher levels of myeloperoxidase, P-selectin, soluble intercellular adhesion molecule 1, and vascular cell adhesion molecule 1. Compared with OAs with SPPB >8, those scoring ≤8 were characterised by smaller muscle volume, greater SAT volume, lower muscle strength, and higher levels of interleukin 1 beta, 6, 10, 12, 13, tumour necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor.

CONCLUSIONS

Multi-block PLS-DA identified distinct patterns of relationships among circulating cytokines and functional and imaging parameters in persons of different ages and varying levels of physical performance. The longitudinal implementation of such an innovative strategy could allow for the tracking of health status over time, the early detection of deviations in health trajectories, and the monitoring of response to treatments.

Associations of Accelerometer-Measured and Self-Reported Sedentary Time With Leukocyte Telomere Length in Older Women

Few studies have assessed the association of sedentary time with leukocyte telomere length (LTL). In a cross-sectional study conducted in 2012-2013, we examined associations of accelerometer-measured and self-reported sedentary time with LTL in a sample of 1,481 older white and African-American women from the Women's Health Initiative and determined whether associations varied by level of moderate- to vigorous-intensity physical activity (MVPA). The association between sedentary time and LTL was evaluated using multiple linear regression models. Women were aged 79.2 (standard deviation, 6.7) years, on average. Self-reported sedentary time was not associated with LTL. In a model adjusting for demographic characteristics, lifestyle behaviors, and health-related factors, among women at or below the median level of accelerometer-measured MVPA, those in the highest quartile of accelerometer-measured sedentary time had significantly shorter LTL than those in the lowest quartile, with an average difference of 170 base pairs (95% confidence interval: 4, 340). Accelerometer-measured sedentary time was not associated with LTL in women above the median level of MVPA. Findings suggest that, on the basis of accelerometer measurements, higher sedentary time may be associated with shorter LTL among less physically active women.

A New Adaptive Home-based Exercise Technology among Older Adults Living in Nursing Home: A Pilot Study on Feasibility, Acceptability and Physical Performance

OBJECTIVES

To explore the feasibility and acceptability of a new home-based exercise technology among older adults and to evaluate its efficacy on physical performance measures.

DESIGN

Longitudinal clinical trial.

SETTING

Oak Hammock at the University of Florida, a nursing home located in Gainesville, Florida.

PARTICIPANTS

Twelve pre-disabled older adults (≥75 years) living in a nursing home with a Short Physical Performance Battery (SPPB) score between 6 and 9 and no diagnosis of dementia.

INTERVENTION

Thirty minutes of light intensity exercise (aerobic, strength and balance) two times per week for four weeks using a home-based physical activity technology called Jintronix.

MEASUREMENTS

Feasibility and acceptability were assessed through a 9-item self-administered questionnaire and by exploring the percentage of quality of movements and time performing exercise which was calculated automatically by Jintronix technology. Physical performance measures were assessed through the SPPB score at baseline, after 4 weeks of intervention and after 3 months from the completion of the intervention.

RESULTS

Twelve older adults (80.5±4.2 years old) performed light intensity exercise with Jintronix for a total of 51.9±7.9 minutes per week. Participants reached 87% score of quality of movements in strength and balance exercises, a global appreciation score of 91.7% and a global difficulty score of 36%. Compared to baseline, there was a significant improvement in SPPB score at the end of the intervention and at 3 months following the completion of the exercise program (0.67±0.98 and 1.08±0.99 respectively, p-value <0.05).

CONCLUSION

Jintronix technology is feasible and acceptable among pre-disabled older adults without dementia living in nursing home and is beneficial in improving their physical performance.

Impact of chemotherapy on medium-term physical function and activity of older breast cancer survivors, and associated biomarkers

OBJECTIVE

Chemotherapy is less often prescribed in older individuals due to concerns about post-treatment morbidity and quality of life. We evaluated the physical performance of breast cancer survivors treated with and without adjuvant chemotherapy.

MATERIALS AND METHODS

We conducted a case-control study in 56 estrogen receptor positive breast cancer survivors (BCS) on adjuvant aromatase inhibitors 1-2years after definitive surgery. Cases had received adjuvant chemotherapy (n=27; age 70.5±3.6years) versus age-matched controls who had not (n=29; age 70.0±4.3years). Measures of grip strength, physical activity and performance, walking speed, fatigue, and self-reported physical function were collected. Biological correlates of inflammation, frailty and markers of DNA and RNA oxidation were compared.

RESULTS

Grip strength (controls: 21±7.4 vs.

CASES

29.7±5.0kg, p=0.20), physical activity (5403±3204 vs. 6801±9320steps/day, p=0.45), physical performance (short physical performance battery score: 10.1±1.8 vs. 10.4±1.1, p=0.52) and long-distance walking speed (1.2±0.21 vs. 1.3±0.41m/s, p=0.17) were similar between the two groups. Self-reported physical function was marginally lower in cases than controls (controls: 72±24 vs.

CASES

57±34AU, p=0.07). Fatigue disruptiveness was not different between groups (controls: 11.1±13.0 vs.

CASES

15.7±16.2AU, p=0.24). Similarly, the inflammation, oxidation, and frailty markers did not present a significant difference between groups, except for vitamin D levels (p=0.04).

CONCLUSION

Older women who received chemotherapy reported having slightly lower physical function, but a similar physical performance compared to women who did not. These data suggest that older BCS treated with chemotherapy recover to an extent similar to survivors who only received hormonal therapy.

Predictors of Change in Physical Function in Older Adults in Response to Long-Term, Structured Physical Activity: The LIFE Study

OBJECTIVES

To evaluate the extent of variability in functional responses in participants in the Lifestyle Interventions and Independence for Elders (LIFE) study and to identify the relative contributions of intervention adherence, physical activity, and demographic and health characteristics to this variability.

DESIGN

Secondary analysis.

SETTING

Multicenter institutions.

PARTICIPANTS

A volunteer sample (N=1635) of sedentary men and women aged 70 to 89 years who were able to walk 400m but had physical limitations, defined as a Short Physical Performance Battery (SPPB) score of ≤9.

INTERVENTIONS

Moderate-intensity physical activity (n=818) consisting of aerobic, resistance, and flexibility exercises performed both center-based (2times/wk) and home-based (3-4times/wk) sessions or health education program (n=817) consisting of weekly to monthly workshops covering relevant health information.

MAIN OUTCOME MEASURES

Physical function (gait speed over 400m) and lower extremity function (SPPB score) assessed at baseline and 6, 12, and 24 months.

RESULTS

Greater baseline physical function (gait speed, SPPB score) was negatively associated with change in gait speed (regression coefficient β=-.185; P<.001) and change in SPPB score (β=-.365; P<.001), whereas higher number of steps per day measured by accelerometry was positively associated with change in gait speed (β=.035; P<.001) and change in SPPB score (β=.525; P<.001). Other baseline factors associated with positive change in gait speed and/or SPPB score include younger age (P<.001), lower body mass index (P<.001), and higher self-reported physical activity (P=.002).

CONCLUSIONS

Several demographic and physical activity-related factors were associated with the extent of change in functional outcomes in participants in the LIFE study. These factors should be considered when designing interventions for improving physical function in older adults with limited mobility.

Using symbolic aggregate approximation (SAX) to visualize activity transitions among older adults

The objective of this analysis was to apply symbolic aggregate approximation (SAX) time-series analysis to accelerometer data for activity pattern visualization stratified by self-reported mobility difficulty. A total of 2393 (71.6  ±  7.9 years old) participants wore an accelerometer on the hip (4  +  d; 10  +  h) during the national health and nutrition examination survey (NHANES), a biannual series of health assessments of the US population. One minute epoch data was used to perform SAX, which converted accelerometry time series data into four activity levels. Intelligent icons of normalized activity transition prevalence, a visual representation of time-series data, were examined among those who self-reported mobility difficulty. Mobility difficulty questions assessed various levels difficulty performing activities such as walking a quarter mile, walking up ten steps, stooping/crouching/kneeling, and walking between rooms on the same floor. Daily activity counts were estimated across difficulty level using weighted-linear regression after adjusted for demographics, lifestyle factors, medical conditions, and accelerometer wear time. Those reporting higher mobility difficulty tended to be older, female, less educated, not married, and smokers. Additionally, those with higher mobility difficulty self-reported lower education, lower income, lower moderate-to-vigorous physical activity, and higher history of adverse medical conditions. Using SAX-derived intelligent icons, those with no difficulty showed high variations of transitions across all activity levels. With higher difficulty, the variations in transitions were lower and constricted around low activity level transitions. Among those who reported unable/don't do mobility-related activities, there were only transitions in the lower tiered activity levels with high prevalence of prolonged low level activity. Adjusted estimates of daily activity were lower as higher difficulty reported occurred but only significant for those reporting unable/don't do mobility-related activity (p  <  0.01). In summary, this analysis showed apparent differences in stratified activity patterns even when traditional regression analyses on volumetric accelerometer data yielded null results.

Effects of blood-flow restriction on biomarkers of myogenesis in response to resistance exercise

We investigated the acute myogenic response to resistance exercise with and without blood-flow restriction (BFR). Six men and women (age, 22 ± 1 years) performed unilateral knee extensions at 40% of 1-repetition maximum with or without (CNTRL) BFR applied via pressure cuff inflated to 220 mm Hg. Muscle biopsies were collected at 4 h and 24 h postexercise. Addition of BFR increased myoD and c-Met messenger RNA expression relative to CNTRL. Expression of hepatocyte growth factor protein was significantly higher following CNTRL.

Actigraphy features for predicting mobility disability in older adults

Actigraphy has attracted much attention for assessing physical activity in the past decade. Many algorithms have been developed to automate the analysis process, but none has targeted a general model to discover related features for detecting or predicting mobility function, or more specifically, mobility impairment and major mobility disability (MMD). Men (N  =  357) and women (N  =  778) aged 70-89 years wore a tri-axial accelerometer (Actigraph GT3X) on the right hip during free-living conditions for 8.4  ±  3.0 d. One-second epoch data were summarized into 67 features. Several machine learning techniques were used to select features from the free-living condition to predict mobility impairment, defined as 400 m walking speed  <0.80 m s^-1. Selected features were also included in a model to predict the first occurrence of MMD-defined as the loss in the ability to walk 400 m. Each method yielded a similar estimate of 400 m walking speed with a root mean square error of ~0.07 m s^-1 and an R-squared values ranging from 0.37-0.41. Sensitivity and specificity of identifying slow walkers was approximately 70% and 80% for all methods, respectively. The top five features, which were related to movement pace and amount (activity counts and steps), length in activity engagement (bout length), accumulation patterns of activity, and movement variability significantly improved the prediction of MMD beyond that found with common covariates (age, diseases, anthropometry, etc). This study identified a subset of actigraphy features collected in free-living conditions that are moderately accurate in identifying persons with clinically-assessed mobility impaired and significantly improve the prediction of MMD. These findings suggest that the combination of features as opposed to a specific feature is important to consider when choosing features and/or combinations of features for prediction of mobility phenotypes in older adults.

Idiopathic chronic fatigue in older adults is linked to impaired mitochondrial content and biogenesis signaling in skeletal muscle

Fatigue is a symptom of many diseases, but it can also manifest as a unique medical condition, such as idiopathic chronic fatigue (ICF). While the prevalence of ICF increases with age, mitochondrial content and function decline with age, which may contribute to ICF. The purpose of this study was to determine whether skeletal muscle mitochondrial dysregulation and oxidative stress is linked to ICF in older adults. Sedentary, old adults (n = 48, age 72.4 ± 5.3 years) were categorized into ICF and non-fatigued (NF) groups based on the FACIT-Fatigue questionnaire. ICF individuals had a FACIT score one standard deviation below the mean for non-anemic adults > 65 years and were excluded according to CDC diagnostic criteria for ICF. Vastus lateralis muscle biopsies were analyzed, showing reductions in mitochondrial content and suppression of mitochondrial regulatory proteins Sirt3, PGC-1α, NRF-1, and cytochrome c in ICF compared to NF. Additionally, mitochondrial morphology proteins, antioxidant enzymes, and lipid peroxidation were unchanged in ICF individuals. Our data suggests older adults with ICF have reduced skeletal muscle mitochondrial content and biogenesis signaling that cannot be accounted for by increased oxidative damage.

Long-Term Cigarette Smoking Trajectories Among HIV-Seropositive and Seronegative MSM in the Multicenter AIDS Cohort Study

To examine the association between demographic characteristics and long-term smoking trajectory group membership among HIV-seropositive and HIV-seronegative men who have sex with men (MSM). A cohort of 6552 MSM from the Multicenter AIDS Cohort Study were asked detailed information about their smoking history since their last follow-up. Group-based trajectory modeling was used to examine smoking behavior and identify trajectory group membership. Because participants enrolled after 2001 were more likely to be younger, HIV-seronegative, non-Hispanic black, and have a high school diploma or less, we also assessed time of enrollment in our analysis. Participants were grouped into 4 distinct smoking trajectory groups: persistent nonsmoker (n = 3737 [55.9 %]), persistent light smoker (n = 663 [11.0 %]), heavy smoker to nonsmoker (n = 531 [10.0 %]), and persistent heavy smoker (n = 1604 [23.1 %]). Compared with persistent nonsmokers, persistent heavy smokers were associated with being enrolled in 2001 and later (adjusted odds ratio [aOR] 2.35; 95 % CI 2.12-2.58), having a high school diploma or less (aOR 3.22; 95 % CI 3.05-3.39), and being HIV-seropositive (aOR 1.17; 95 % CI 1.01-1.34). These associations were statistically significant across all trajectory groups for time of enrollment and education but not for HIV serostatus. The overall decrease of smoking as shown by our trajectory groups is consistent with the national trend. Characteristics associated with smoking group trajectory membership should be considered in the development of targeted smoking cessation interventions among MSM and people living with HIV.