ABSTRACT
Dysregulated rest-activity rhythm (RAR) patterns have been associated with several health conditions in older adults. This study showed that later acrophase was associated with a modestly greater risk of falls but not fractures in elderly men. Associations between dysregulated RAR patterns and osteoporosis risk warrant further investigation. PURPOSE: The purpose of this study was to investigate the relationship between rest-activity rhythm (RAR) patterns and risk of falls/fractures in older men. We hypothesized that dysregulated RAR would be associated with incident falls/fractures. METHODS: We used wrist-worn actigraphy to measure RAR over 4.8 ± 0.8 24-h periods in men (≥67 years) enrolled in the multicenter Outcomes of Sleep Disorders in Men (MrOS Sleep) Study (n = 3001). Men were contacted every 4 months to report occurrence of falls/fractures. RAR parameters included amplitude (difference between peak and nadir activity in counts/minute), mesor (activity counts/minute), acrophase (time of day of peak activity), and pseudo-F statistic (rhythm robustness) and were evaluated as continuous variables with associations reported per SD increase/decrease in models adjusted for confounders. Logistic regression was used to estimate the likelihood (odds ratio, OR) of recurrent falls in the year after the visit. Proportional hazards models were used to estimate the risk (hazard ratio, HR) of fractures. RESULTS: One year after the visit, 417 men (14%) had recurrent (≥2) falls. Later acrophase (OR 1.18, 95% CI 1.06-1.32) was associated with a modestly greater likelihood of falls. In 8.6 years (SD 2.6 years) of >97% complete follow-up, 256 men (8.53%) had a major osteoporotic fracture, 85 (2.8%) had a clinical spine fracture, and 110 (3.7%) had a hip fracture. No consistent, significant associations were observed between RAR patterns and fractures. CONCLUSIONS: Later acrophase was associated with a modestly greater risk of falls; this association did not translate into a higher fracture risk in this cohort of elderly men.
Subject(s)
Accidental Falls , Exercise/physiology , Osteoporotic Fractures/physiopathology , Rest/physiology , Actigraphy , Aged , Aged, 80 and over , Aging/physiology , Bone Density/physiology , Circadian Clocks/physiology , Femur Neck/physiopathology , Follow-Up Studies , Humans , Male , Prospective Studies , Recurrence , Risk FactorsABSTRACT
OBJECTIVE: Sleep disturbances are common in older adults. Little is known about the sleep of cognitively intact older adults and its relationship to subsequent cognitive impairment. The objective of this study was to examine the association between objective sleep-wake measures and risk of incident cognitive impairment. METHODS: In this prospective cohort study encompassing four U.S. sites, 1,245 women (mean age: 82.6 years) without dementia participated in the Study of Osteoporotic Fractures and completed actigraphy at the baseline visit and comprehensive cognitive assessment at follow-up. The association between sleep-wake patterns measured by actigraphy and risk of incident mild cognitive impairment (MCI) and dementia was examined. RESULTS: A total of 473 women (38%) developed cognitive impairment during an average (SD) follow-up of 4.9 (0.6) years; 290 (23.3%) developed MCI and 183 (14.7%) developed dementia. After controlling for multiple potential confounders, women in the lowest quartile of average sleep efficiency (<74%) had a 1.5-fold higher odds of developing MCI or dementia compared with women in the highest quartile of sleep efficiency (>86%) (odds ratio: Q1 versus Q4 1.53; 95% CI: 1.07, 2.19; Wald χ(2) [1, N = 1,223] = 5.34 for p for trend = 0.03). Longer average sleep latency, but not total sleep time, was also associated with higher odds of developing cognitive impairment. Greater variability in both sleep efficiency and total sleep time was associated with an increased odds of developing MCI or dementia. CONCLUSION: Lower average sleep efficiency, longer average sleep latency, and greater variability in sleep efficiency and total sleep time are associated with increased odds of developing cognitive impairment. Further research is needed to explore the mechanisms underlying these associations.
Subject(s)
Aging/psychology , Cognitive Dysfunction/complications , Cognitive Dysfunction/psychology , Dementia/complications , Dementia/psychology , Sleep Initiation and Maintenance Disorders/complications , Sleep Initiation and Maintenance Disorders/psychology , Actigraphy , Aged, 80 and over , Female , Humans , Neuropsychological Tests , Predictive Value of Tests , Prospective Studies , Risk FactorsABSTRACT
BACKGROUND: Frailty can occur in older adults without disability or multimorbidity. Current methods focus on the most frail, but poorly discriminate among those "not frail." METHODS: The Study of Muscle, Mobility, and Aging (SOMMA) included 879 adults aged 70 years and older without mobility disability. We operationalized frailty domains using: peak oxygen consumption (endurance), digit symbol substitution test (speed), leg power (strength), perceived fatigability, D3 creatine dilution (sarcopenia), and accelerometry (sedentary behavior) to construct a frailty score of 0-12 summing tertiles (0-2) of each component. We used linear or logistic regression with and without adjustment for confounders to examine associations with age, reported, and performance function. RESULTS: The SOMMA frailty score distribution was broad and strongly associated with age (râ =â 0.33, pâ <â .0001). Each point was associated with a 30%-50% higher odds of having reported difficulty with activities of daily living or mobility. After grouping the total score (0-3, 4-7, and 8-12) those in the highest group were 9-31 times more likely to have functional limitation, and at least 8 times more likely to have poorer function after full adjustment. Higher scores identified those less likely to report ease of walking or higher physical activity. Peak oxygen consumption, leg power, fatigability, and digit symbol score contributed most to these associations. CONCLUSIONS: The SOMMA frailty score characterizes frailty as a continuum from frail to vigorous with assessments that are amenable to change. Associations with age and function suggest utility for distinguishing a wide range of vigor and vulnerability in relatively well-functioning older adults.
Subject(s)
Frailty , Aged , Humans , Aged, 80 and over , Frailty/diagnosis , Activities of Daily Living , Geriatric Assessment , Aging , MusclesABSTRACT
BACKGROUND: The effects of aging on circadian patterns of behavior are insufficiently described. To address this, we characterized age-specific features of rest-activity rhythms (RAR) in community-dwelling older adults both overall, and in relation, to sociodemographic characteristics. METHODS: We examined cross-sectional associations between RAR and age, sex, race, education, multimorbidity burden, financial, work, martial, health, and smoking status using assessments of older adults with wrist-worn free-living actigraphy data (Nâ =â 820, ageâ =â 76.4 years, 58.2% women) participating in the Study of Muscle, Mobility, and Aging (SOMMA). RAR parameters were determined by mapping an extension to the traditional cosine curve to activity data. Functional principal component analysis determined variables accounting for variance. RESULTS: Age was associated with several metrics of dampened RAR; women had stronger and more robust RAR versus men (all pâ <â .05). Total activity (56%) and time of activity (20%) accounted for most of the RAR variance. Compared to the latest decile of acrophase, those in the earliest decile had higher average amplitude (pâ <â .001). Compared to the latest decile of acrophase, those in the earliest and midrange categories had more total activity (pâ =â .02). Being in a married-like relationship and a more stable financial situation were associated with stronger rhythms; higher education was associated with less rhythm strength (all pâ <â .05). CONCLUSIONS: Older age was associated with dampened circadian behavior; behaviors were sexually dimorphic. Some sociodemographic characteristics were associated with circadian behavior. We identified a behavioral phenotype characterized by early time of day of peak activity, high rhythmic amplitude, and more total activity.
Subject(s)
Circadian Rhythm , Rest , Male , Humans , Female , Aged , Cross-Sectional Studies , Rest/physiology , Circadian Rhythm/physiology , Aging/physiology , Actigraphy , Muscles , Sleep/physiologyABSTRACT
BACKGROUND: How magnetic resonance (MR) derived thigh muscle volume and deuterated creatine dilution derived muscle mass (D3Cr muscle mass) differentially relate to strength, fitness, and other functions in older adults-and whether associations vary by sex-is not known. METHODS: Men (Nâ =â 345) and women (Nâ =â 482) aged ≥70 years from the Study of Muscle, Mobility, and Aging completed leg extension strength (1-repetition max) and cardiopulmonary exercise testing to assess fitness (VO2peak). Correlations and adjusted regression models stratified by sex were used to assess the association between muscle size measures, study outcomes, and sex interactions. RESULTS: D3Cr muscle mass and MR thigh muscle volume were correlated (men: râ =â 0.62, women: râ =â 0.51, pâ <â .001). Each standard deviation (SD) decrement in D3Cr muscle mass was associated with lower 1-repetition max strength (-14 kg men, -4 kg women, pâ <â .001 for both; p-interactionâ =â .003) and lower VO2peak (-79 mL/min men, -30 mL/min women, pâ <â .001 for both, p-interaction: .016). Each SD decrement in MR thigh muscle volume was also associated with lower strength (-32 kg men, -20 kg women, pâ <â .001 for both; p-interactionâ =â .139) and lower VO2peak (-217 mL/min men, -111 mL/min women, pâ <â .001 for both, p-interactionâ =â .010). There were associations, though less consistent, between muscle size or mass with physical performance and function; associations varied by sex. CONCLUSIONS: Less muscle-measured by either D3Cr muscle mass or MR thigh muscle volume-was associated with lower strength and fitness. Varied associations by sex and assessment method suggest consideration be given to which measurement to use in future studies.
Subject(s)
Muscle, Skeletal , Thigh , Male , Humans , Female , Aged , Muscle, Skeletal/physiology , Aging/physiology , Physical Functional Performance , Magnetic Resonance Spectroscopy , Muscle Strength/physiologyABSTRACT
PURPOSE: Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (VÌO 2peak ) declines with aging and correlates with mortality and morbidity. Cardiopulmonary exercise testing (CPET) is the criterion method to assess CRF, but its feasibility, validity, and reliability in older adults are unclear. Our objective was to design and implement a dependable, safe, and reliable CPET protocol in older adults. METHODS: VÌO 2peak was measured by CPET, performed using treadmill exercise in 875 adults ≥70 yr in the Study of Muscle, Mobility and Aging (SOMMA). The protocol included a symptom-limited peak (maximal) exercise and two submaximal walking speeds. An adjudication process was in place to review tests for validity if they met any prespecified criteria (VÌO 2peak <12.0 mL·kg -1 ·min -1 ; maximum heart rate <100 bpm; respiratory exchange ratio <1.05 and a rating of perceived exertion <15). A subset ( N = 30) performed a repeat test to assess reproducibility. RESULTS: CPET was safe and well tolerated, with 95.8% of participants able to complete the VÌO 2peak phase of the protocol. Only 56 (6.4%) participants had a risk alert and only two adverse events occurred: a fall and atrial fibrillation. Mean ± SD VÌO 2peak was 20.2 ± 4.8 mL·kg -1 ·min -1 , peak heart rate 142 ± 18 bpm, and peak respiratory exchange ratio 1.14 ± 0.09. Adjudication was indicated in 47 tests; 20 were evaluated as valid and 27 as invalid (18 data collection errors, 9 did not reach VÌO 2peak ). Reproducibility of VÌO 2peak was high (intraclass correlation coefficient = 0.97). CONCLUSIONS: CPET was feasible, effective, and safe for older adults, including many with multimorbidity or frailty. These data support a broader implementation of CPET to provide insight into the role of CRF and its underlying determinants of aging and age-related conditions.
Subject(s)
Cardiorespiratory Fitness , Exercise Test , Oxygen Consumption , Humans , Aged , Exercise Test/methods , Cardiorespiratory Fitness/physiology , Oxygen Consumption/physiology , Male , Female , Prospective Studies , Reproducibility of Results , Heart Rate/physiology , Feasibility Studies , Aged, 80 and overABSTRACT
BACKGROUND: Slower gait speed may be driven by greater energy deficits and fatigability among older adults. We examined associations of walking energetics and perceived physical fatigability with gait speed among slower and faster walkers. Additionally, we used statistical mediation to examine the role of fatigability in the associations of walking energetics and gait speed using the Study of Muscle, Mobility and Aging (SOMMA). METHODS: Perceived physical fatigability was assessed using the Pittsburgh Fatigability Scale (PFS) Physical score (range 0-50, higherâ =â greater). A 3-phase cardiopulmonary exercise treadmill test collected peak oxygen consumption (VO2peak, mL/kg/min), energetic cost of walking (ECW, mL/kg/m), and cost-capacity ratio (VO2/VO2peak*100, %). Slower (<1.01 m/s) versus faster (≥1.01 m/s) walkers were classified using median 4-m gait speed. Linear regressions and statistical mediation analyses were conducted. RESULTS: Slower walkers had lower VO2peak, higher ECW at preferred walking speed (PWS), and greater PFS Physical score compared to faster walkers (all pâ <â .05; Nâ =â 849). One standard deviation (1-SD) higher VO2peak was associated with 0.1 m/s faster gait speed, while 1-SD higher ECW PWS, cost-capacity ratio at PWS and slow walking speed (SWS), and PFS Physical score were associated with 0.02-0.23 m/s slower gait speed. PFS Physical score was a significant statistical mediator in the associations between VO2peak (15.2%), SWS cost-capacity ratio (15.9%), and ECW PWS (10.7%) with gait speed and was stronger among slower walkers. CONCLUSIONS: Slower walkers may be more influenced by perceptions of fatigue in addition to walking energetics. Our work highlights the importance of targeting both energetics and perceived fatigability to prevent mobility decline.
Subject(s)
Energy Metabolism , Fatigue , Oxygen Consumption , Walking Speed , Walking , Humans , Male , Walking Speed/physiology , Female , Aged , Energy Metabolism/physiology , Oxygen Consumption/physiology , Fatigue/physiopathology , Walking/physiology , Exercise Test/methods , Aging/physiology , Middle Aged , Aged, 80 and overABSTRACT
BACKGROUND: Phenotypic frailty syndrome identifies older adults at greater risk for adverse health outcomes. Despite the critical role of mitochondria in maintaining cellular function, including energy production, the associations between muscle mitochondrial energetics and frailty have not been widely explored in a large, well-phenotyped, older population. METHODS: The Study of Muscle, Mobility and Aging (SOMMA) assessed muscle energetics in older adults (N = 879, mean age = 76.3 years, 59.2% women). 31Phosporous magnetic resonance spectroscopy measured maximal production of adenosine triphosphate (ATPmax) in vivo, while ex vivo high-resolution respirometry of permeabilized muscle fibers from the vastus lateralis measured maximal oxygen consumption supported by fatty acids and complex I- and II-linked carbohydrates (e.g., Max OXPHOSCI+CII). Five frailty criteria, shrinking, weakness, exhaustion, slowness, and low activity, were used to classify participants as robust (0, N = 397), intermediate (1-2, N = 410), or frail (≥ 3, N = 66). We estimated the proportional odds ratio (POR) for greater frailty, adjusted for multiple potential confounders. RESULTS: One-SD decrements of most respirometry measures (e.g., Max OXPHOSCI+CII, adjusted POR = 1.5, 95%CI [1.2,1.8], p = 0.0001) were significantly associated with greater frailty classification. The associations of ATPmax with frailty were weaker than those between Max OXPHOSCI+CII and frailty. Muscle energetics was most strongly associated with slowness and low physical activity components. CONCLUSIONS: Our data suggest that deficits in muscle mitochondrial energetics may be a biological driver of frailty in older adults. On the other hand, we did observe differential relationships between measures of muscle mitochondrial energetics and the individual components of frailty.
Subject(s)
Frailty , Male , Aged , Humans , Female , Frail Elderly , Muscles , Aging , Mitochondria , Adenosine TriphosphateABSTRACT
BACKGROUND: Skeletal muscle energetics decline with age, and physical activity (PA) has been shown to offset these declines in older adults. Yet, many studies reporting these effects were based on self-reported PA or structured exercise interventions. Therefore, we examined the associations of accelerometry-measured and self-reported PA and sedentary behavior (SB) with skeletal muscle energetics and explored the extent to which PA and sedentary behavior would attenuate the associations of age with muscle energetics. METHODS: As part of the Study of Muscle, Mobility and Aging, enrolled older adults (nâ¯=â¯879), 810 (ageâ¯=â¯76.4 ± 5.0 years old, mean ± SD; 58% women) had maximal muscle oxidative capacity measured ex vivo via high-resolution respirometry of permeabilized myofibers (maximal oxidative phosphorylation (maxOXPHOS)) and in vivo by 31phosphorus magnetic resonance spectroscopy (maximal adenosine triphosphate (ATPmax)). Accelerometry-measured sedentary behavior, light activity, and moderate-to-vigorous PA (MVPA) were assessed using a wrist-worn ActiGraph GT9X over 7 days. Self-reported sedentary behavior, MVPA, and all PA were assessed with the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire. Linear regression models with progressive covariate adjustments evaluated the associations of sedentary behavior and PA with muscle energetics, as well as the attenuation of the age/muscle energetics association by MVPA and sedentary behavior. As a sensitivity analysis, we also examined activPAL-measured daily step count and time spent in sedentary behavior and their associations with muscle energetics. RESULTS: Every 30 min/day more of ActiGraph-measured MVPA was associated with 0.65 pmol/(s × mg) higher maxOXPHOS and 0.012 mM/s higher ATPmax after adjusting for age, site/technician, and sex (p < 0.05). Light activity was not associated with maxOXPHOS or ATPmax. Meanwhile, every 30 min/day spent in ActiGraph-measured sedentary behavior was associated with 0.39 pmol/sâ¯×â¯mg lower maxOXPHOS and 0.006 mM/s lower ATPmax (p < 0.05). Only associations with ATPmax held after further adjusting for socioeconomic status, body mass index, lifestyle factors, and multimorbidity. CHAMPS MVPA and all PA yielded similar associations with maxOXPHOS and ATPmax (p < 0.05), but sedentary behavior did not. Higher activPAL step count was associated with higher maxOXHPOS and ATPmax (p < 0.05), but time spent in sedentary behavior was not. Additionally, age was significantly associated with muscle energetics for men only (p < 0.05); adjusting for time spent in ActiGraph-measured MVPA attenuated the age association with ATPmax by 58% in men. CONCLUSION: More time spent in accelerometry-measured or self-reported daily PA, especially MVPA, was associated with higher skeletal muscle energetics. Interventions aimed specifically at increasing higher intensity activity might offer potential therapeutic interventions to slow age-related decline in muscle energetics. Our work also emphasizes the importance of taking PA into consideration when evaluating associations related to skeletal muscle energetics.
Subject(s)
Accelerometry , Energy Metabolism , Exercise , Muscle, Skeletal , Sedentary Behavior , Self Report , Humans , Aged , Female , Male , Exercise/physiology , Muscle, Skeletal/metabolism , Muscle, Skeletal/physiology , Energy Metabolism/physiology , Aged, 80 and over , Aging/physiology , Aging/metabolism , Oxidative Phosphorylation , Adenosine Triphosphate/metabolismABSTRACT
BACKGROUND: The geroscience hypothesis posits that aging biological processes contribute to many age-related deficits, including the accumulation of multiple chronic diseases. Though only one facet of mitochondrial function, declines in muscle mitochondrial bioenergetic capacities may contribute to this increased susceptibility to multimorbidity. METHODS: The Study of Muscle, Mobility and Aging (SOMMA) assessed ex vivo muscle mitochondrial energetics in 764 older adults (mean ageâ =â 76.4, 56.5% women, and 85.9% non-Hispanic White) by high-resolution respirometry of permeabilized muscle fibers. We estimated the proportional odds ratio (POR [95% CI]) for the likelihood of greater multimorbidity (4 levels: 0 conditions, Nâ =â 332; 1 condition, Nâ =â 299; 2 conditions, Nâ =â 98; or 3+ conditions, Nâ =â 35) from an index of 11 conditions, per SD decrement in muscle mitochondrial energetic parameters. Distribution of conditions allowed for testing the associations of maximal muscle energetics with some individual conditions. RESULTS: Lower oxidative phosphorylation supported by fatty acids and/or complex I- and II-linked carbohydrates (eg, Max OXPHOSCI+CII) was associated with a greater multimorbidity index score (PORâ =â 1.32 [1.13, 1.54]) and separately with diabetes mellitus (ORâ =â 1.62 [1.26, 2.09]), depressive symptoms (ORâ =â 1.45 [1.04, 2.00]) and possibly chronic kidney disease (ORâ =â 1.57 [0.98, 2.52]) but not significantly with other conditions (eg, cardiac arrhythmia, chronic obstructive pulmonary disease). CONCLUSIONS: Lower muscle mitochondrial bioenergetic capacities were associated with a worse composite multimorbidity index score. Our results suggest that decrements in muscle mitochondrial energetics may contribute to a greater global burden of disease and are more strongly related to some conditions than others.
Subject(s)
Aging , Energy Metabolism , Mitochondria, Muscle , Multimorbidity , Humans , Female , Aged , Male , Energy Metabolism/physiology , Mitochondria, Muscle/metabolism , Aging/metabolism , Aging/physiology , Aged, 80 and over , Muscle, Skeletal/metabolismABSTRACT
BACKGROUND: Older men with the worse alignment of activity and light may have lower levels of cognition and increased rates of cognitive decline. METHODS: This cohort consisted of 1 036 older men (81.1 ± 4.6 years) from the MrOS Sleep Study (2009-2012). Light and activity levels were gathered by wrist actigraphy. Phasor analysis was used to quantify the alignment of light-dark and rest-activity patterns (magnitude) and their temporal relationship (angle). Global cognitive function (Modified Mini-Mental State examination [3MS]) and executive function (Trails B test) were measured, then repeated 4.2 ± 0.8 years later. Linear regression models examined the associations of phasor magnitude and angle with cognition and cognitive decline. Models were adjusted for age, clinic, race, education, and season. RESULTS: Smaller phasor magnitude (worse aligned light and activity patterns) was associated with lower initial level and increased decline in executive function. Compared to those with higher phasor magnitude, those with lower magnitude took an average of 11.1 seconds longer to complete the Trails B test (quartile 1 vs quartile 4, p = .02). After follow-up, Trails B completion time increased an average of 5.5 seconds per standard deviation decrease in phasor magnitude (95% confidence interval [CI] 0.7-10.4, p = .03). There were no associations with phasor angle, and none with magnitude and global cognition (3MS). CONCLUSION: Among older men, worse alignment of light and activity patterns was associated with worse initial performance and increased decline in executive function, but not related to global cognition. Interventions that improve the alignment of light and activity may slow cognitive decline in older adults.
Subject(s)
Cognition Disorders , Cognitive Dysfunction , Male , Humans , Aged , Cognitive Dysfunction/etiology , Polysomnography , Cognition , SleepABSTRACT
BACKGROUND: Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (VO2peak) declines with aging and correlates with mortality and morbidity. Cardiopulmonary Exercise Testing (CPET) has long been the criterion method to assess CRF, but its feasibility, efficacy and reliability in older adults is unclear. The large, multicenter Study of Muscle, Mobility and Aging (SOMMA) employed CPET to evaluate the mechanisms underlying declines in mobility with aging among community-dwelling older adults. Our primary objective was to design and implement a CPET protocol in older adults that was dependable, safe, scientifically valuable, and methodologically reliable. METHODS: CPET was performed using treadmill exercise in 875 adults ≥70 years. A composite protocol included a symptom-limited peak exercise phase and two submaximal phases to assess cardiopulmonary ventilatory indices during 1) participants' preferred walking speed and 2) at slow walking speed of 1.5 mph (0.67 m/s). An adjudication process was in place to review tests for validity if they met any prespecified criteria (VO2peak <12.0 ml/kg/min; maximum heart rate (HR) <100 bpm; respiratory exchange ratio (RER) <1.05 and a rating of perceived exertion <15). A repeat test was performed in a subset (N=30) to assess reproducibility. RESULTS: CPET was safe and well tolerated, with 95.8% of participants able to complete the VO2peak phase of the protocol. Only 56 (6.4%) participants had a risk alert during any phase of testing and only two adverse events occurred during the peak phase: a fall and atrial fibrillation. The average ± standard deviation for VO2peak was 20.2 ± 4.8 mL/kg/min, peak HR 142 ± 18 bpm, and peak RER 1.14 ± 0.09. VO2peak and RER were slightly higher in men than women. Adjudication was indicated in 47 participants; 20 were evaluated as valid, 27 as invalid (18 had a data collection error, 9 did not reach VO2peak). Reproducibility of VO2peak was high (intraclass correlation coefficient=0.97). CONCLUSIONS: CPET was feasible, effective and safe for community-dwelling older adults, many of whom had multimorbidity and frailty. These data support a broader implementation of CPET to provide important insight into the role of CRF and its underlying determinants in aging and age-related conditions and diseases. Clinical Perspective: What Is New?: Performing cardiopulmonary exercise testing in a community dwelling older adult with multimorbidities or frailty is feasible and exceptionally safe under highly trained exercise physiologists and physician supervision.Reproducibility of VO2peak among community-dwelling older adults with significant clinical complexity was high (intraclass correlation coefficient=0.97).The VO2peak observed was comparable to established normative data for older adults, and adds merit to the limited data collected on VO2peak norms in older adults.What Are the Clinical Implications?: Ventilatory gas collection during clinical cardiac stress testing may be valuable to plan of care in routine management of older adults due to the important role of aerobic fitness on morbidity and mortality.Cardiopulmonary exercise testing can provide insight into the role of cardiorespiratory fitness and its underlying determinants in aging and age-related conditions and diseases.
ABSTRACT
Background: Aging is associated with declines in circadian functions. The effects of aging on circadian patterns of behavior are insufficiently described. We characterized age-specific features of rest-activity rhythms (RAR) in community dwelling older adults, both overall, and in relation, to sociodemographic characteristics. Methods: We analyzed baseline assessments of older adults with wrist-worn free-living wrist-worn actigraphy data (N=820, Age=76.4 yrs, 58.2% women) participating in the Study of Muscle, Mobility and Aging (SOMMA). We applied an extension to the traditional cosine curve to map RAR to activity data, calculating the parameters: rhythmic strength (amplitude); robustness (pseudo-F statistic); and timing of peak activity (acrophase). We also used function principal component analysis to determine 4 components describing underlying patterns of activity accounting for RAR variance. Linear models were used to examine associations between RAR and sociodemographic variables. Results: Age was associated with several metrics of dampened RAR; women had stronger and more robust RAR metrics vs. men (all P < 0.05). Total activity (56%) and time of activity (20%) accounted for most the RAR variance. Compared to the latest decile of acrophase, those in the earliest decile had higher average amplitude (P <0.001). Compared to the latest decile of acrophase, those is the earliest and midrange categories had more total activity (P=0.02). RAR was associated with some sociodemographic variables. Conclusions: Older age was associated with dampened circadian behavior; and behaviors were sexually dimorphic. We identified a behavioral phenotype characterized by early time-of-day of peak activity, high rhythmic amplitude, and more total activity.
ABSTRACT
Background: Skeletal muscle energetics decline with age, and physical activity (PA) has been shown to counteract these declines in older adults. Yet, many studies were based on self-reported PA or structured exercise interventions. We examined the associations of objective daily PA and sedentary behavior (SB) with skeletal muscle energetics and also compared with self-reported PA and SB. We also explored the extent to which PA would attenuate the associations of age with muscle energetics. Methods: Among the Study of Muscle, Mobility and Aging (SOMMA) enrolled older adults, 810 (mean age=76±5, 58% women) had maximal muscle oxidative capacity measured ex vivo via high-resolution respirometry of permeabilized myofibers (maxOXPHOS) and in vivo by 31 Phosphorus magnetic resonance spectroscopy (ATP max ). Objective PA was measured using the wrist-worn ActiGraph GT9X over 7-days to capture sedentary behavior (SB), light, and moderate-to-vigorous PA (MVPA). Self-reported SB, MVPA, and all exercise-related PA were assessed with The Community Healthy Activities Model Program for Seniors questionnaire. Linear regression models with progressive covariate adjustments evaluated the associations between SB, PA and muscle energetics, and the attenuation of the age / muscle energetic association by PA. Results: Every 30 minutes more objective MVPA was associated with 0.65 pmol/s*mg higher maxOXPHOS and 0.012 mM/sec higher ATP max , after adjustment for age, site/technician and sex. More time spent in objective light+MVPA was significantly associated with higher ATP max , but not maxOXPHOS. In contrast, every 30 minutes spent in objective SB was associated with 0.43 pmol/s*mg lower maxOXPHOS and 0.004 mM/sec lower ATP max . Only associations with ATP max held after further adjusting for socioeconomic status, body mass index, lifestyle factors and multimorbidities. Self-reported MVPA and all exercise-related activities, but not SB, yielded similar associations with maxOXPHOS and ATP max . Lastly, age was only significantly associated with muscle energetics in men. Adjusting for objective time spent in MVPA attenuated the age association with ATP max by nearly 60% in men. Conclusion: More time spent in daily PA, especially MVPA, were associated with higher muscle energetics. Interventions that increase higher intensity activity might offer potential therapeutic interventions to slow the age-related decline in muscle energetics. Our work also emphasizes the importance of taking PA into consideration when evaluating associations related to skeletal muscle energetics.
ABSTRACT
Background: Different measures to assess muscle size - magnetic resonance (MR) derived thigh muscle volume and d3-creatine dilution derived muscle mass (D3Cr muscle mass) - may have similar associations with strength, power, physical performance, fitness, and functional limitations in older adults. Methods: Men (N=345) and women (N=482) aged ≥70 years from the Study of Muscle, Mobility and Aging completed exams including leg extension strength (1-repetition max) and cardiopulmonary exercise testing to assess fitness (VO2peak). Correlations and adjusted regression models stratified by sex were used to assess the association between muscle size measures and study outcomes; we tested for sex interactions. Results: D3Cr muscle mass and MR thigh muscle volume were correlated (men: r=0.62, women: r=0.51, p<.001). Lower D3Cr muscle mass and lower MR thigh muscle volume were associated with lower strength and lower VO2peak in both men and women; D3Cr muscle mass was more strongly associated with strength in men than in women (p-int<0.05). There were correlations, though less consistent, between muscle size or mass with physical performance and function. Associations between the muscle size measures and the study outcomes occasionally varied by sex, and associations of MR thigh muscle volume were, at times, slightly more strongly associated with the study outcomes than was D3Cr muscle mass. Conclusions: Less muscle -measured by either D3Cr muscle mass or MR thigh muscle volume - was associated with lower strength and worse performance. Varied associations by sex and assessment method suggest consideration be given to which measurement to use in future studies.
ABSTRACT
Use of antidepressant medications has been associated with increased risk of fracture, but prior studies have been limited by incomplete control of confounders or a limited number of fractures. Use of antidepressant medications by 8,217 community-dwelling women aged 69 and older from a population-based prospective cohort study at four US clinical centers was assessed by interview at four examinations over a 10-year period, beginning in 1992-1994. Use was coded as a time-dependent variable. Incident fractures occurring after the initial medication assessment until July 2007 were confirmed by radiographic reports. Potential confounders were included in multivariable models and updated at each follow-up visit. Compared to nonusers of antidepressant medications, women using SSRIs experienced a higher risk of nonspine fracture in age-adjusted models (HR = 1.36, 95% CI 1.11-1.67) and in multivariable models controlling for potential confounders (HR = 1.30, 95% CI 1.04-1.62). SSRI use was not associated with an increased risk of first hip fracture (HR = 1.01, 95% CI 0.71-1.44) but was associated with an increased risk of wrist fracture (HR = 1.54, 95% CI 1.01-2.36). TCA use was associated with an increased risk of nonspine fracture in age-adjusted models, but in multivariable models this risk was attenuated. SSRI use was associated with a higher risk of any nonspine fracture, but not hip fracture, in this cohort of older women. TCA use was associated with a higher risk of nonspine fracture, but this association was in part explained by confounding factors.
Subject(s)
Antidepressive Agents/adverse effects , Antidepressive Agents/therapeutic use , Fractures, Bone/etiology , Age Factors , Aged , Aged, 80 and over , Aging/drug effects , Aging/physiology , Antidepressive Agents, Tricyclic/adverse effects , Antidepressive Agents, Tricyclic/therapeutic use , Bone Density/drug effects , Cohort Studies , Female , Fractures, Bone/chemically induced , Fractures, Bone/epidemiology , Humans , Interviews as Topic , Risk Factors , Selective Serotonin Reuptake Inhibitors/adverse effects , Selective Serotonin Reuptake Inhibitors/therapeutic useABSTRACT
BACKGROUND: Evaluating asymmetries in muscle function could provide important insights for fall risk assessments. We sought to determine the associations of (i) handgrip strength (HGS) asymmetry and (ii) leg extension power (LEP) asymmetry on risk of incident recurrent falls and fractures in older men. METHOD: There were 5 730 men with HGS asymmetry data and 5 347 men with LEP asymmetry data from the Osteoporotic Fractures in Men (MrOS) study. A handgrip dynamometer measured HGS and a Nottingham Power Rig ascertained LEP. Percent difference in maximal HGS between hands was calculated, and asymmetric HGS was defined as men in the highest quartile of dissimilarity for HGS between hands. The same approach was used to determine asymmetric LEP. Participants self-reported falls every 4 months after the baseline exam, and persons with ≥2 falls in the first year were considered recurrent fallers. Fractures and their dates of occurrence were self-reported and confirmed with radiographic reports. RESULTS: Older men in the highest HGS asymmetry quartile had a 1.20 (95% confidence interval [CI]: 1.01-1.43) relative risk for incident recurrent falls. Likewise, men in the highest HGS asymmetry quartile had a higher risk for incident fractures: 1.41 (CI: 1.02-1.96) for hip, 1.28 (CI: 1.04-1.58) for major osteoporotic, and 1.24 (CI: 1.06-1.45) for nonspine. There were no significant associations between LEP asymmetry and recurrent falls or fractures. CONCLUSIONS: Asymmetric HGS could be a novel risk factor for falls and fractures that is more feasible to measure than LEP. Fall risk assessments should consider evaluating muscle function, including HGS asymmetry.
Subject(s)
Hand Strength , Leg , Aged , Humans , Male , Risk Factors , Self ReportABSTRACT
STUDY OBJECTIVES: To estimate the association of self-reported poor sleep in multiple dimensions with health care costs in older men. METHODS: Participants were 1,413 men (mean [SD] age 76.5 [5.7] years) enrolled in both the Outcomes of Sleep Disorders in Older Men (MrOS Sleep) study and Medicare Fee-for-Service. Poor sleep was characterized at the baseline MrOS Sleep visit on five dimensions (satisfaction, daytime sleepiness, timing, latency, and duration). Health care costs and utilization were ascertained over 3 years of follow-up using Medicare Claims. RESULTS: Median (interquartile range [IQR]) annualized total health care costs (2018 US dollars) rose from $3,616 (IQR 1,523-7,875) for those with no impaired sleep dimensions to $4,416 (IQR 1,854-11,343) for men with two impaired sleep dimensions and $5,819 (IQR 1,936-15,569) for those with at least three impaired sleep dimensions. After multivariable adjustment, the ratio of total health care costs (CR) was significantly higher for men with two (1.24, 95% confidence interval [CI] 1.03- to 1.48) and men with at least three impaired sleep dimensions (1.78, 95% CI 1.42 to 2.23) vs. those with no impaired sleep dimensions. After excluding 101 men who died during the 3-year follow-up period, these associations were attenuated and not significant (CR 1.22, 95% CI 0.98 to 1.53 for men ≥3 impaired sleep dimensions vs. none). CONCLUSIONS: Self-reported poor sleep on multiple dimensions is associated with higher subsequent total health care costs in older men, but this may be due to higher mortality and increased health care costs toward the end of life among those with poor sleep health.
Subject(s)
Health Care Costs , Medicare , Aged , Humans , Male , Polysomnography , Self Report , Sleep , United States/epidemiologyABSTRACT
STUDY OBJECTIVES: Determine the association of poor multidimensional sleep health with health-care costs and utilization. METHODS: We linked 1,459 community-dwelling women (mean age 83.6 years) participating in the Study of Osteoporotic Fractures Year 16 visit (2002-2004) with their Medicare claims. Five dimensions of sleep health (satisfaction, daytime sleepiness, timing, latency, and duration) were assessed by self-report. The number of impaired dimensions was expressed as a score (range 0-5). Total direct health-care costs and utilization were ascertained during the subsequent 36 months. RESULTS: Mean (SD) total health-care costs/year (2017 dollars) increased in a graded manner across the sleep health score ranging from $10,745 ($15,795) among women with no impairment to up to $15,332 ($22,810) in women with impairment in three to five dimensions (p = 0.01). After adjustment for age, race, and enrollment site, women with impairment in three to five dimensions vs. no impairment had greater mean total costs (cost ratio [CR] 1.34 [95% CI = 1.13 to 1.60]) and appeared to be at higher risk of hospitalization (odds ratio (OR) 1.31 [95% CI = 0.96 to 1.81]). After further accounting for number of medical conditions, functional limitations, and depressive symptoms, impairment in three to five sleep health dimensions was not associated with total costs (CR 1.02 [95% CI = 0.86 to 1.22]) or hospitalization (OR 0.91 [95% CI = 0.65 to 1.28]). Poor multidimensional sleep health was not related to outpatient costs or risk of skilled nursing facility stay. CONCLUSIONS: Older women with poor sleep health have higher subsequent total health-care costs largely attributable to their greater burden of medical conditions, functional limitations, and depressive symptoms.
Subject(s)
Medicare , Sleep Wake Disorders , Aged , Aged, 80 and over , Female , Health Care Costs , Hospitalization , Humans , Independent Living , Sleep , Sleep Wake Disorders/epidemiology , United States/epidemiologyABSTRACT
BACKGROUND: Serotonin transporters have recently been described in bone, raising the possibility that medications that block serotonin reuptake could affect bone metabolism. METHODS: We assessed current use of selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) and obtained serial bone mineral density (BMD) measurements in a cohort of 2722 older women (mean age, 78.5 years) participating in the Study of Osteoporotic Fractures, a prospective cohort study of community-dwelling women. Hip BMD was measured at the sixth examination and an average of 4.9 years later at the eighth examination. We categorized women as nonusers (used no SSRIs or TCAs at either examination; n=2406), SSRI users (used SSRIs but no TCAs at either examination; n=198), or TCA users (used TCAs but no SSRIs at either examination; n=118). Depressive symptoms were identified using a cutoff score of at least 6 on the Geriatric Depression Scale. RESULTS: After adjustment for potential confounders, including the Geriatric Depression Scale score, mean total hip BMD decreased 0.47% per year in nonusers compared with 0.82% in SSRI users (P<.001) and 0.47% in TCA users (P=.99). Higher rates of bone loss were also observed at the 2 hip subregions for SSRI users. Results were not substantially altered when women who scored at least 6 on the Geriatric Depression Scale were excluded from the analysis. CONCLUSION: Use of SSRIs but not TCAs is associated with an increased rate of bone loss at the hip in this cohort of older women.