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Background: Osteoporosis is generally thought of as a "woman's disease" because the prevalence of osteoporosis and the rate of fractures are much higher in postmenopausal women than in older men. However, the absolute number of men affected by osteoporosis and fractures is large, as at least 2.8 million men in the United States are thought to have osteoporosis.Questions/purposes: The purposes of this review are to (1) highlight gender differences in osteoporosis and fracture risk, (2) describe disparities in treatment and outcomes after fractures between men and women, and (3) propose solutions to reducing disparities in treatment and prevention.Methods: A literature survey was conducted using MEDLINE with a variety of search terms and using references from the author's personal collection of articles. A formal search strategy and exclusion criteria were not employed and the review is therefore selective. WHERE ARE WE NOW?: Postmenopausal women have a higher prevalence of osteoporosis and greater incidence of fracture than older men. Despite the higher fracture risk in postmenopausal women, older men tend to have worse outcomes after fracture and poorer treatment rates, although less is known about the disease course in men. Multifaceted interventions to improve the screening and treatment for osteoporosis were recently developed. WHERE DO WE NEED TO GO?: Improvement in treatment rates of those at risk, regardless of gender, is an important goal in osteoporosis management. HOW DO WE GET THERE?: Further development and evaluation of cost-effective, multifaceted interventions for screening and treatment of osteoporosis and fractures are needed; such interventions will likely improve the primary prevention of fractures. [ABSTRACT FROM AUTHOR]

This study examined the consistency of the Nottingham power rig in assessing leg extension power in older men, assessed between different examiners with adjustment for the order of measurement (time) and clinic. Fifty-five men (mean, 73 yrs) enrolled in the Osteoporotic Fractures in Men Study had maximum leg extension power of each leg measured at baseline and remeasured 1 wk later. There was a significant effect of time (P < 0.01). The second visit had an average increase in leg extension power (right leg, 14.2 W; left leg, 16.5 W). After accounting for the effect of time, a low coefficient of variation was observed between examiners (right leg 3.49%; left leg 3.46%). Data from the two time points corresponded reasonably well. The effect of time and fatigue should be considered when performing this measurement. The Nottingham power rig provided a reproducible measure of leg extension power in this multisite study of older men. [ABSTRACT FROM AUTHOR]

Background: A standard phenotype of frailty was associated with an increased risk of adverse outcomes including mortality in a recent study of older adults. However, the predictive validity of this phenotype for fracture outcomes and across risk subgroups is uncertain.Methods: To determine whether a standard frailty phenotype was independently associated with risk of adverse health outcomes in older women and to evaluate the consistency of associations across risk subgroups defined by age and body mass index (BMI), we ascertained frailty status in a cohort of 6724 women>or=69 years and followed them prospectively for incident falls, fractures, and mortality. Frailty was defined by the presence of three or more of the following criteria: unintentional weight loss, weakness, self-reported poor energy, slow walking speed, and low physical activity. Incident recurrent falls were defined as at least two falls during the subsequent year. Incident fractures (confirmed with x-ray reports), including hip fractures, and deaths were ascertained during an average of 9 years of follow-up.Results: After controlling for multiple confounders such as age, health status, medical conditions, functional status, depressive symptoms, cognitive function, and bone mineral density, frail women were subsequently at increased risk of recurrent falls (multivariate odds ratio=1.38, 95% confidence interval [CI], 1.02-1.88), hip fracture (multivariate hazards ratio [MHR]=1.40, 95% CI, 1.03-1.90), any nonspine fracture (MHR=1.25, 95% CI, 1.05-1.49), and death (MHR=1.82, 95% CI, 1.56-2.13). The associations between frailty and these outcomes persisted among women>or=80 years. In addition, associations between frailty and an increased risk of falls, fracture, and mortality were consistently observed across categories of BMI, including BMI>or=30 kg/m2.Conclusion: Frailty is an independent predictor of adverse health outcomes in older women, including very elderly women and older obese women. [ABSTRACT FROM AUTHOR]

Background: Prediction of long-term survival in healthy adults requires recognition of features that serve as early indicators of successful aging. The aims of this study were to identify predictors of long-term survival in older women and to develop a multivariable model based upon longitudinal data from the Study of Osteoporotic Fractures (SOF).Methods: We considered only the youngest subjects (n = 4,097) enrolled in the SOF cohort (65 to 69 years of age) and excluded older SOF subjects more likely to exhibit a "frail" phenotype. A total of 377 phenotypic measures were screened to determine which were of most value for prediction of long-term (19-year) survival. Prognostic capacity of individual predictors, and combinations of predictors, was evaluated using a cross-validation criterion with prediction accuracy assessed according to time-specific AUC statistics.Results: Visual contrast sensitivity score was among the top 5 individual predictors relative to all 377 variables evaluated (mean AUC = 0.570). A 13-variable model with strong predictive performance was generated using a forward search strategy (mean AUC = 0.673). Variables within this model included a measure of physical function, smoking and diabetes status, self-reported health, contrast sensitivity, and functional status indices reflecting cumulative number of daily living impairments (HR >or= 0.879 or RH Conclusions: The multivariate model we developed characterizes a "healthy aging" phenotype based upon an integration of measures that together reflect multiple dimensions of an aging adult (65-69 years of age). Age-sensitive components of this model may be of value as biomarkers in human studies that evaluate anti-aging interventions. Our methodology could be applied to data from other longitudinal cohorts to generalize these findings, identify additional predictors of long-term survival, and to further develop the "healthy aging" concept. [ABSTRACT FROM AUTHOR]

Background: This study quantifies incremental healthcare expenditures of functional impairments and phenotypic frailty in specific healthcare sectors., Methods: Pooled 2023 analysis of 4 prospective cohort studies linked with Medicare claims including 4 318 women and 3 847 men attending an index examination (2002-2011). Annualized inpatient, skilled nursing facility (SNF), home healthcare (HHC), and outpatient costs (2023 dollars) ascertained for 36 months following index examination. Functional impairments (difficulty performing 4 activities of daily living) and frailty phenotype (operationalized using 5 components) derived from cohort data. Weighted multimorbidity index including demographics derived from claims., Results: Mean age at index examination was 79.2 years. After accounting for multimorbidity and each other, average annualized incremental costs of 3-4 functional impairments versus no impairment in women (men) were $2 838 ($5 516) in inpatient, $1 572 ($1 446) in SNF, and $1 349 ($1 060) in HHC sectors; average incremental costs of phenotypic frailty versus robust in women (men) was $4 100 (not significant for men) in inpatient, $1 579 ($1 254) in SNF, and $645 ($526) in HHC sectors. Incremental inpatient costs were primarily due to a higher hospitalization risk, while incremental SNF and HHC costs were related to both increased risks of utilization and higher costs among individuals with utilization. Neither geriatric domain was associated with outpatient costs., Conclusions: In this study of community-dwelling beneficiaries, functional impairments were independently associated with higher subsequent expenditures in inpatient, SNF, and HHC sectors among both sexes. Phenotypic frailty was independently associated with higher subsequent inpatient costs in women, and higher SNF and HHC costs in both sexes., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Muscle strength, as measured by handgrip strength (HGS), is associated with physical function and mortality. Yet the environmental context that influences muscle strength is poorly understood. We evaluated built and social neighborhood characteristics and their association with muscle strength over time., Methods: Using data from the Health and Retirement Study (2006-2018), linear mixed models assessed how 11 built and social neighborhood variables were associated with baseline levels and changes in HGS over time., Results: Among the 20 045 respondents (mean age = 63 years, standard deviation = 9.7) with up to 4 HGS measures, 8 455 were men and 11 590 were women. Among men, residing in a neighborhood with a 10% increment higher score on neighborhood disadvantage was associated with a ~1 kg lower HGS at baseline (B = -0.96 kg, 95% confidence interval [CI] = -1.39 to -0.53). Similarly, each 1-point increment on the physical disorder scale was associated with a -0.39 kg lower (95% CI = -0.65 to -0.12) baseline HGS value. Among women, each 10% increment in neighborhood disadvantage was associated with a 0.29 kg lower HGS at baseline (B = -0.29 kg for each 10% increment, 95% CI = -0.46, -0.13). Each 1-unit increment in the number of neighborhood gyms at baseline was associated with a 0.50 kg lower HGS (B = -0.50, 95% CI = -0.76 to -0.23). Each 1-point increment in physical disorder was associated with a -0.12 kg lower (95% CI = -0.24 to -0.00) baseline HGS value. None of the neighborhood features were associated with the HGS rate of change., Conclusions: Findings suggest that residing in neighborhoods with greater disadvantages and physical disorders may pose challenges for HGS among middle-aged adults as they enter into older adulthood., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America.)

Background: Very little is known about specific trajectories or patterns of falls over time. Using the well-characterized cohort of the Osteoporotic Fractures in Men Study (MrOS), we classified individuals by fall trajectories across age and identified predictors of group assignment based on characteristics at baseline., Methods: Using an analysis sample of 5 976 MrOS participants and 15 years of follow-up data on incident falls, we used group-based trajectory models (PROC TRAJ in SAS) to identify trajectories of change. We assessed the association of baseline characteristics with group assignment using 1-way analysis of variance and chi-square tests. Multivariable logistic regression was used to analyze the outcome of the high-risk fall trajectory groups compared to the low-risk groups., Results: Changes in rates of falls were relatively constant or increasing with 5 distinct groups identified. Mean posterior probabilities for all 5 trajectories were similar and consistently above 0.8 indicating a reasonable model fit. Among the 5 fall trajectory groups, 2 were deemed high risk, those with steeply increasing fall risk and persistently high fall risk. Factors associated with fall risk included body mass index, use of central nervous agents, prior history of diabetes and Parkinson's disease, back pain, grip strength, and physical and mental health scores., Conclusions: Two distinct groups of high fall risk individuals were identified among 5 trajectory groups, those with steeply increasing fall risk and persistently high fall risk. Statistically significant characteristics for group assignment suggest that future fall risk of older men may be predictable at baseline., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Low neighborhood socioeconomic status is associated with adverse health outcomes, but its association with health care costs in older adults is uncertain., Objectives: To estimate the association of neighborhood Area Deprivation Index (ADI) with total, inpatient, outpatient, skilled nursing facility (SNF), and home health care (HHC) costs among older community-dwelling Medicare beneficiaries, and determine whether these associations are explained by multimorbidity, phenotypic frailty, or functional impairments., Design: Four prospective cohort studies linked with each other and with Medicare claims., Participants: In total, 8165 community-dwelling fee-for-service beneficiaries (mean age 79.2 years, 52.9% female)., Main Measures: ADI of participant residence census tract, Hierarchical Conditions Category multimorbidity score, self-reported functional impairments (difficulty performing four activities of daily living), and frailty phenotype. Total, inpatient, outpatient, post-acute SNF, and HHC costs (US 2020 dollars) for 36 months after the index examination., Key Results: Mean incremental annualized total health care costs adjusted for age, race/ethnicity, and sex increased with ADI ($3317 [95% CI 1274 to 5360] for the most deprived vs least deprived ADI quintile, and overall p-value for ADI variable 0.009). The incremental cost for the most deprived vs least deprived ADI quintile was increasingly attenuated after separate adjustment for multimorbidity ($2407 [95% CI 416 to 4398], overall ADI p-value 0.066), frailty phenotype ($1962 [95% CI 11 to 3913], overall ADI p-value 0.22), or functional impairments ($1246 [95% CI -706 to 3198], overall ADI p-value 0.29)., Conclusions: Total health care costs are higher for older community-dwelling Medicare beneficiaries residing in the most socioeconomically deprived areas compared to the least deprived areas. This association was not significant after accounting for the higher prevalence of phenotypic frailty and functional impairments among residents of socioeconomically deprived neighborhoods., Competing Interests: Declarations Conflict of Interest The authors declare that they do not have a conflict of interest., (© 2024. The Author(s), under exclusive licence to Society of General Internal Medicine.)

Objective: Sociodemographic, lifestyle, and medical variables influence total testosterone (T) and sex hormone-binding globulin (SHBG) concentrations. The relationship between these factors and "free" T remains unclear. We examined 21 sociodemographic, lifestyle, and medical predictors influencing calculated free T (cFT) in community-dwelling men across ages., Design: This is a cross-sectional analysis in 20 631 participants in the Androgens in Men Study., Methods: Individual participant data (IPD) were provided by 9 cohorts. Total T was determined using mass spectrometry, SHBG using immunoassays, and cFT using the Vermeulen formula. Associations were analyzed using 2-stage random effects IPD meta-analyses., Results: Cohort median ages ranged from 40 to 76 years and median cFT concentrations from 174.3 to 422.8 pmol/L. In men aged 17-99 years, there was a linear inverse association of cFT with age (-57.2 pmol/L [95% confidence interval, -69.4, -44.9] per 1 SD increase in age). Calculated free T increased with increasing baseline body mass index (BMI) among men with BMI < 23.6 kg/m2, but decreased among men with BMI > 23.6 kg/m2 (-24.7 pmol/L [-29.1, -20.3] per 1 SD increase in the 25.4-29.6 kg/m2 BMI range). Calculated free T was lower in younger men, who were married or in a de facto relationship (-18.4 pmol/L [-27.6, -9.3]) and in men who formerly smoked (-5.7 pmol/L [-8.9, -2.6]), were in poor general health (-14.0 pmol/L [-20.1, -7.8]), and had diabetes (-19.6 pmol/L [-23.0, -16.3]), cardiovascular disease (-5.8 pmol/L [-8.3, -3.2]), or cancer (-19.2 pmol/L [-24.4, -14.1])., Conclusions: Calculated free T was most prominently associated with age and BMI. The linear, inverse association with age, nonlinear association with BMI, and presence of diabetes, cancer, and sociodemographic factors should be considered when interpreting cFT values., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Greater perceived physical fatigability and lower skeletal muscle energetics are both predictors of mobility decline. Characterizing associations between muscle energetics and perceived fatigability may provide insight into potential targets to prevent mobility decline. We examined associations of in vivo (maximal ATP production, ATPmax) and ex vivo (maximal carbohydrate supported oxidative phosphorylation [max OXPHOS] and maximal fatty acid supported OXPHOS [max FAO OXPHOS]) measures of mitochondrial energetics with two measures of perceived physical fatigability, Pittsburgh Fatigability Scale (PFS, 0-50, higher = greater) and Rating of Perceived Exertion (RPE Fatigability, 6-20, higher = greater) after a slow treadmill walk. Participants from the Study of Muscle, Mobility and Aging (N = 873) were 76.3 ± 5.0 years old, 59.2% women, and 85.3% White. Higher muscle energetics (both in vivo and ex vivo) were associated with lower perceived physical fatigability, all p < 0.03. When stratified by sex, higher ATPmax was associated with lower PFS Physical for men only; higher max OXPHOS and max FAO OXPHOS were associated with lower RPE Fatigability for both sexes. Higher skeletal muscle energetics were associated with 40-55% lower odds of being in the most (PFS ≥ 25, RPE Fatigability ≥ 12) vs least (PFS 0-4, RPE Fatigability 6-7) severe fatigability strata, all p < 0.03. Being a woman was associated with 2-3 times higher odds of being in the most severe fatigability strata when controlling for ATPmax but not the ex vivo measures (p < 0.05). Better mitochondrial energetics were linked to lower fatigability and less severe fatigability in older adults. Findings imply that improving skeletal muscle energetics may mitigate perceived physical fatigability and prolong healthy aging., (© 2024. The Author(s), under exclusive licence to American Aging Association.)

Background: A higher difference in estimated glomerular filtration rate by cystatin C versus creatinine (eGFRDiff = eGFRCys - eGFRCreat) is associated with decreased frailty risk. Since eGFRCreat is influenced by muscle more than eGFRCys, muscle mass may explain this association. Previous work could not account for this when considering regional muscle measures by imaging. Deuterated creatine (D 3 Cr) dilution measures whole body muscle mass (kilograms). We aimed to determine whether eGFRDiff is associated with D 3 Cr muscle mass and whether muscle mass explains the association between eGFRDiff and frailty., Methods: Cross-sectional analysis within the multicenter MrOS Study at Year 14 (visit 4). 490 men of the original cohort of 5994 MrOS participants (aged ≥65 at enrollment) were included. Exposure was eGFRDiff (= eGFRCys - eGFRCreat), calculated using CKD-EPI equations 2012/2021. Primary outcome was D 3 Cr muscle mass. Secondary outcome was phenotypic pre-frailty (one or two criteria) and frailty (≥three criteria) including the following: weight loss, weakness, slow gait, physical activity, poor energy. The association of eGFRDiff with D 3 Cr muscle mass was examined by linear regression, that with prefrailty / frailty by multinomial logistic regression., Results: Mean ± SD age was 84 ± 4 years, eGFRCreat 68 ± 16, eGFRCys 52 ± 16, eGFRDiff -15 ± 12 mL/min/1.73 m 2 and D 3 Cr muscle mass 24 ± 4 kg. For each SD increment in eGFRDiff, D3Cr muscle mass was 1.4 kg higher on average, p < 0.0001 (fully adjusted). Higher eGFRDiff was associated with lower odds of frailty (OR = 0.63 95% CI [0.45;0.89]), but this was partially attenuated and insignificant after additionally adjusting for D 3 Cr muscle mass (OR = 0.85 95% CI [0.58; 1.24])., Conclusions: Higher eGFRDiff is associated with lower odds of frailty among late-life men. D 3 Cr muscle mass accounts for some of this association. This suggests that non-GFR determinants of creatinine and cystatin C, such as muscle mass, play a role in explaining the association of eGFRDiff with frailty. Future studies are needed to confirm., (© 2024 The Author(s). Journal of the American Geriatrics Society published by Wiley Periodicals LLC on behalf of The American Geriatrics Society.)

Physical activity (PA), sedentary behavior (SB), and sleep are each individually associated with falls and fractures, but often are not examined simultaneously. Compositional data analysis examined the combined prospective associations between the proportion of time in PA, SB, and sleep relative to the remaining behaviors with recurrent falls (2+ falls in any year), any fractures, and major osteoporotic fracture (MOF) from tri-annual questionnaires, with adjudication for fractures, in 2918 older men aged 78.9 ± 5.1 years in the Osteoporotic Fractures in Men (MrOS) Study. Accelerometers were worn on the right tricep for seven consecutive 24-hour periods and measured PA (>1.5 METs), SB (≤1.5 METs), and sleep. Generalized Estimating Equations evaluated associations with recurrent falls. Cox proportional hazards regression estimated any incident fracture and MOF risk separately. Over four years of follow-up 1025 (35.2%) experienced recurrent falls; over 10 ± 4 years of follow-up, 669 (22.9%) experienced incident fractures and 370 (12.7%) experienced a MOF. Higher proportions of PA relative to SB and sleep were associated with a lower odds of recurrent falls [Odds Ratio (OR): 0.87, 95% CI: 0.76-0.99]. Higher proportions of SB relative to PA and sleep were associated with a higher odds of recurrent falls (OR: 1.38, 95% CI: 1.06-1.81) and higher risk of any fracture [Hazard Ratio (HR): 1.42, 95% CI: 1.05-1.92]. Higher proportions of sleep relative to PA and SB were associated with a lower risk of fracture (HR: 0.74, 95% CI: 0.54-0.99). No associations of activity composition with MOF were observed. When accounting for the co-dependence of daily activities, higher proportions of SB relative to the proportion of PA and sleep were associated with higher odds of recurrent falls and fracture risk. Results suggest reducing SB (and increasing PA) may lower fall and fracture risk in older men, which could inform future interventions., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research.)

Sarcopenia is the accelerated loss of skeletal muscle mass and function commonly, but not exclusively, associated with advancing age. It is observed across many species including humans in whom it can lead to decline in physical function and mobility as well as to increased risk of adverse outcomes including falls, fractures and premature mortality. Although prevalence estimates vary because sarcopenia has been defined in different ways, even using a conservative approach, the prevalence is between 5% and 10% in the general population. A life course framework has been proposed for understanding not only the occurrence of sarcopenia in later life but also influences operating at earlier life stages with potentially important implications for preventive strategies. Harnessing progress in understanding the hallmarks of ageing has been key to understanding sarcopenia pathophysiology. Considerable convergence in approaches to diagnosis of sarcopenia has occurred over the last 10 years, with a growing emphasis on the central importance of muscle strength. Resistance exercise is currently the mainstay of treatment; however, it is not suitable for all. Hence, adjunctive and alternative treatments to improve quality of life are needed. An internationally agreed approach to definition and diagnosis will enable a step change in the field and is likely to be available in the near future through the Global Leadership Initiative in Sarcopenia., (© 2024. Springer Nature Limited.)

Objectives: This study examined whether changes in late-life physical performance are associated with contemporaneous changes in blood pressure (BP) in older men., Design: prospective cohort study over 7 years., Setting and Participants: Physical performance (gait speed, grip strength, chair stand performance) and clinic-measured BP at baseline and at least one follow-up (year 7 or 9) were assessed in 3,135 men aged ≥65 y enrolled in the Osteoporotic Fractures in Men Study (MrOS)., Methods: Generalized estimating equation analysis of multivariable models with standardized point estimates (β [95% CI]) described longitudinal associations between physical performance and BP changes in participants overall, and stratified by baseline cardiovascular disease (CVD), antihypertensive medication use (none, ≥1), and enrollment age (<75 years; ≥75 years)., Results: Overall, positive associations (z-score units) were found between each increment increase in gait speed and systolic (SBP) (0.74 [0.22, 1.26]) and grip strength (0.35 [0.04, 0.65]) or gait speed (0.55 [0.24, 0.85]) with diastolic (DBP). Better grip strength and chair stand performance over time were associated with 1.83 [0.74, 2.91] and 3.47 [0.20, 6.74] mmHg higher SBP, respectively in men with CVD at baseline (both interaction P < .05). Gait speed increases were associated with higher SBP in men without CVD (0.76 [0.21, 1.32]), antihypertensive medication non-users (0.96 [0.30, 1.62]), aged <75 years (0.73 [0.05, 1.41]) and ≥75 years (0.76 [0.06, 1.47]). Similar positive, but modest associations for DBP were observed with grip strength in men with CVD, antihypertensive medication non-users, and aged <75 years, and with gait speed in men without CVD, aged <75 years, and irrespective of antihypertensive medication use., Conclusion: In older men, better physical performance is longitudinally associated with higher BP. Mechanisms and implications of these seemingly paradoxical findings, which appears to be modified by CVD status, antihypertensive medication use, and age, requires further investigation., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

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 (n = 879), 810 (age = 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 31 phosphorus magnetic resonance spectroscopy (maximal adenosine triphosphate (ATP max )). 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 ATP max after adjusting for age, site/technician, and sex (p < 0.05). Light activity was not associated with maxOXPHOS or ATP max . Meanwhile, every 30 min/day spent in ActiGraph-measured sedentary behavior was associated with 0.39 pmol/s × mg lower maxOXPHOS and 0.006 mM/s lower ATP max (p < 0.05). Only associations with ATP max 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 ATP max (p < 0.05), but sedentary behavior did not. Higher activPAL step count was associated with higher maxOXHPOS and ATP max (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 ATP max 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., (Copyright © 2024. Production and hosting by Elsevier B.V.)

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, higher = 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 p < .05; N = 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., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Although low back pain (LBP) may persist or recur over time, few studies have evaluated the individual course of LBP over a long-term period, particularly among older adults. Based on data from the longitudinal Osteoporotic Fractures in Men (MrOS) Study, we aimed to identify and describe different LBP trajectories in older men and characterize members in each trajectory group. A total of 5 976 community-dwelling men (mean age = 74.2) enrolled at 6 U.S. sites were analyzed. Participants self-reported LBP (yes/no) every 4 months for a maximum of 10 years. Latent class growth modeling was performed to identify unique LBP trajectory groups that explained variation in the LBP data. The association of baseline characteristics with trajectory group membership was assessed using univariable and multivariable multinominal logistic regression. A 5-class solution was chosen; no/rare LBP (n = 2 442/40.9%), low frequency-stable LBP (n = 1 040/17.4%), low frequency-increasing LBP (n = 719/12%), moderate frequency-decreasing LBP (n = 745/12.5%), and high frequency-stable LBP (n = 1 030/17.2%). History of falls (OR = 1.52), history of LBP (OR = 6.37), higher physical impairment (OR = 1.51-2.85), and worse psychological function (OR = 1.41-1.62) at baseline were all associated with worse LBP trajectory groups in this sample of older men. These findings present an opportunity for targeted interventions and/or management to older men with worse or increasing LBP trajectories and associated modifiable risk factors to reduce the impact of LBP and improve quality of life., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America.)

Purpose: Cardiorespiratory fitness (CRF) measured by peak oxygen consumption (V̇O 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: V̇O 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 (V̇O 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 V̇O 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 V̇O 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 V̇O 2peak ). Reproducibility of V̇O 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., (Copyright © 2024 by the American College of Sports Medicine.)

Diabetes mellitus (DM) is associated with increased fracture risk in White adults. However, the impact of DM on fractures in Black adults is unknown. This systematic review and meta-analysis investigated the association between DM and fractures in adults of African ancestry. MEDLINE, Scopus, CINAHL and Embase databases were searched from their inception up to November 2023 for all studies in the English language investigating the epidemiology of fractures (prevalence, incidence, or risk) in Black men and women (age ≥ 18 years) with type 1 or type 2 DM. Effect sizes for prevalence of previous fractures (%) and incident fracture risk (hazard ratio [HR]) were calculated using a random-effects model on Stata (version 18.0). There were 13 eligible studies, of which 12 were conducted in Black adults from the United States, while one was conducted in adults of West African ancestry from Trinidad and Tobago. We found no fracture data in Black adults with DM living in Africa. Five studies were included in a meta-analysis of incident fracture risk, reporting data from 2926 Black and 6531 White adults with DM. There was increased risk of fractures in Black adults with DM compared to non-DM (HR = 1.65; 95 % confidence interval [CI]: 1.14, 2.39). The risk of fractures was also higher in White adults with DM compared to non-DM (HR = 1.31; 95 % CI: 1.06, 1.61) among these studies. Five studies were included in a meta-analysis of fracture prevalence, of which three also reported fracture prevalence in White adults. There were 175 previous fractures among 993 Black adults with DM and 384 previous fractures among 1467 White adults with DM, with a pooled prevalence of 17.5 % (95 % CI: 15.4, 19.6) and 25.8 % (95 % CI: 4.8, 46.8), respectively. Our results indicate a high burden of fractures in Black adults with DM., Competing Interests: Declaration of competing interest The authors declare that they have no conflict/s of interest. There was no internal and/or external source of funding for the present study., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: We evaluated whether more severe back pain phenotypes-persistent, frequent, or disabling back pain-are associated with higher mortality rate among older men., Methods: In this secondary analysis of a prospective cohort, the Osteoporotic Fractures in Men (MrOS) study, we evaluated mortality rates by back pain phenotype among 5215 older community-dwelling men (mean age, 73 years, SD = 5.6) from 6 sites in the United States. The primary back pain measure used baseline and Year 5 back pain questionnaire data to characterize participants as having no back pain, nonpersistent back pain, infrequent persistent back pain, or frequent persistent back pain. Secondary measures of back pain from the Year 5 questionnaire included disabling back pain phenotypes. The main outcomes measured were all-cause and cause-specific death., Results: After the Year 5 exam, during up to 18 years of follow-up (mean follow-up = 10.3 years), there were 3513 deaths (1218 cardiovascular, 764 cancer, 1531 other). A higher proportion of men with frequent persistent back pain versus no back pain died (78% versus 69%; sociodemographic-adjusted HR = 1.27, 95% CI = 1.11-1.45). No association was evident after further adjustment for health-related factors, such as self-reported general health and comorbid chronic health conditions (fully adjusted HR = 1.00; 95% CI = 0.86-1.15). Results were similar for cardiovascular deaths and other deaths, but we observed no association of back pain with cancer deaths. Secondary back pain measures, including back-related disability, were associated with increased mortality risk that remained statistically significant in fully adjusted models., Conclusion: Although frequent persistent back pain was not independently associated with risk of death in older men, additional secondary disabling back pain phenotypes were independently associated with increased mortality rate. Future investigations should evaluate whether improvements in disabling back pain affect general health and well-being or risk of death., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Our objective was to investigate the overall and sex-specific relationships between the presence and severity of knee osteoarthritis (KOA) and muscle composition, power, and energetics in older adults., Methods: Male and female patients (n = 655, mean ± SD age 76.1 ± 4.9 years; 57% female) enrolled in the Study of Muscle, Mobility, and Aging completed standing knee radiographs and knee pain assessments. Participants were divided into three groups using Kellgren-Lawrence grade (KLG) of KOA severity (0-1, 2, or 3-4). Outcome measures included whole-body muscle mass, thigh fat-free muscle (FFM) volume and muscle fat infiltration (MFI), leg power, specific power (power normalized to muscle volume), and muscle mitochondrial energetics., Results: Overall, the presence and severity of KOA is associated with greater MFI, lower leg power and specific power, and reduced oxidative phosphorylation (P trend < 0.036). Sex-specific analysis revealed reduced energetics only in female patients with KOA (P trend < 0.007) compared to female patients without KOA. In models adjusted for age, sex, race, nonsteroidal anti-inflammatory drug administration, site or technician, physical activity, height, and participants with abdominal adiposity with KLG 3 to 4 had greater MFI (mean 0.008%, 95% confidence interval [CI] 0.004%-0.011%) and lower leg power (mean -51.56 W, 95% CI -74.03 to -29.10 W) and specific power (mean -5.38 W/L, 95% CI -7.31 to -3.45 W/L) than those with KLG 0 to 1. No interactions were found between pain and KLG status. Among those with KOA, MFI and oxidative phosphorylation were associated with thigh FFM volume, leg power, and specific power., Conclusion: Muscle health is associated with the presence and severity of KOA and differs by sex. Although muscle composition and power are lower in both male and female patients with KOA, regardless of pain status, mitochondrial energetics is reduced only in female patients., (© 2024 The Author(s). Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

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 age = 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, N = 332; 1 condition, N = 299; 2 conditions, N = 98; or 3+ conditions, N = 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 (POR = 1.32 [1.13, 1.54]) and separately with diabetes mellitus (OR = 1.62 [1.26, 2.09]), depressive symptoms (OR = 1.45 [1.04, 2.00]) and possibly chronic kidney disease (OR = 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., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Tryptophan (TRP) metabolites along the kynurenine (KYN) pathway (KP) have been found to influence muscle. Proinflammatory cytokines are known to stimulate the degradation of TRP down the KP. Given that both inflammation and KP metabolites have been connected with loss of muscle, we assessed the potential mediating role of KP metabolites on inflammation and muscle mass in older men. Five hundred and five men (85.0 ± 4.2 years) from the Osteoporotic Fractures in Men cohort study with measured D3-creatine dilution (D3Cr) muscle mass, KP metabolites, and inflammation markers (C-reactive protein [CRP], alpha-1-acid glycoprotein [AGP] and a subsample [n = 305] with interleukin [IL-6, IL-1β, IL-17A] and tumor necrosis factor-α [TNF-α]) were included in the analysis. KP metabolites and inflammatory markers were measured using liquid chromatography-tandem mass spectrometry and immunoassays, respectively. 23%-92% of the inverse relationship between inflammatory markers and D3Cr muscle mass was mediated by KP metabolites (indirect effect p < .05). 3-hydroxyanthranilic acid (3-HAA), quinolinic acid (QA), TRP, xanthurenic acid (XA), KYN/TRP, 3-hydroxykynurenine (3-HK)/3-HAA, QA/3-HAA, and nicotinamide (NAM)/QA mediated the AGP relationship. 3-HAA, QA, KYN/TRP, 3-HK/XA, HKr ratio, 3-HK/3-HAA, QA/3-HAA, and NAM/QA mediated the CRP. KYN/TRP, 3-HK/XA, and NAM/QA explained the relationship for IL-6 and 3-HK/XA and QA/3-HAA for TNF-α. No mediation effect was observed for the other cytokines (indirect effect p > .05). KP metabolites, particularly higher ratios of KYN/TRP, 3-HK/XA, 3-HK/3-HAA, QA/3-HAA, and a lower ratio of NAM/QA, mediated the relationship between inflammation and low muscle mass. Our preliminary cross-sectional data suggest that interventions to alter D3Cr muscle mass may focus on KP metabolites rather than inflammation per se., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Cardiorespiratory fitness and mitochondrial oxidative capacity are associated with reduced walking speed in older adults, but their impact on walking speed in older adults with diabetes has not been clearly defined. We examined differences in cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity between older adults with and without diabetes, as well as determined their relative contribution to slower walking speed in older adults with diabetes. Participants with diabetes (n = 159) had lower cardiorespiratory fitness and mitochondrial respiration in permeabilized fiber bundles compared with those without diabetes (n = 717), following adjustments for covariates including BMI, chronic comorbid health conditions, and physical activity. Four-meter and 400-m walking speeds were slower in those with diabetes. Mitochondrial oxidative capacity alone or combined with cardiorespiratory fitness mediated ∼20-70% of the difference in walking speed between older adults with and without diabetes. Additional adjustments for BMI and comorbidities further explained the group differences in walking speed. Cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity contribute to slower walking speeds in older adults with diabetes., (© 2024 by the American Diabetes Association.)

Importance: While adults aged 80 years and older account for 70% of hip fractures in the US, performance of fracture risk assessment tools in this population is uncertain., Objective: To compare performance of the Fracture Risk Assessment Tool (FRAX), Garvan Fracture Risk Calculator, and femoral neck bone mineral density (FNBMD) alone in 5-year hip fracture prediction., Design, Setting and Participants: Prognostic analysis of 3 prospective cohort studies including participants attending an index examination (1997 to 2016) at age 80 years or older. Data were analyzed from March 2023 to April 2024., Main Outcomes and Measures: Participants contacted every 4 or 6 months after index examination to ascertain incident hip fractures and vital status. Predicted 5-year hip fracture probabilities calculated using FRAX and Garvan models incorporating FNBMD and FNBMD alone. Model discrimination assessed by area under receiver operating characteristic curve (AUC). Model calibration assessed by comparing observed vs predicted hip fracture probabilities within predicted risk quintiles., Results: A total of 8890 participants were included, with a mean (SD) age at index examination of 82.6 (2.7) years; 4906 participants (55.2%) were women, 866 (9.7%) were Black, 7836 (88.1%) were White, and 188 (2.1%) were other races and ethnicities. During 5-year follow-up, 321 women (6.5%) and 123 men (3.1%) experienced a hip fracture; 818 women (16.7%) and 921 men (23.1%) died before hip fracture. Among women, AUC was 0.69 (95% CI, 0.67-0.72) for FRAX, 0.69 (95% CI, 0.66-0.72) for Garvan, and 0.72 (95% CI, 0.69-0.75) for FNBMD alone (FNBMD superior to FRAX, P = .01; and Garvan, P = .01). Among men, AUC was 0.71 (95% CI, 0.66-0.75) for FRAX, 0.76 (95% CI, 0.72-0.81) for Garvan, and 0.77 (95% CI, 0.72-0.81) for FNBMD alone (P < .001 Garvan and FNBMD alone superior to FRAX). Among both sexes, Garvan greatly overestimated hip fracture risk among individuals in upper quintiles of predicted risk, while FRAX modestly underestimated risk among those in intermediate quintiles of predicted risk., Conclusions and Relevance: In this prognostic study of adults aged 80 years and older, FRAX and Garvan tools incorporating FNBMD compared with FNBMD alone did not improve 5-year hip fracture discrimination. FRAX modestly underpredicted observed hip fracture probability in intermediate-risk individuals. Garvan markedly overpredicted observed hip fracture probability in high-risk individuals. Until better prediction tools are available, clinicians should prioritize consideration of hip BMD, life expectancy, and patient preferences in decision-making regarding drug treatment initiation for hip fracture prevention in late-life adults.

Autophagy is essential for proteostasis, energetic balance, and cell defense and is a key pathway in aging. Identifying associations between autophagy gene expression patterns in skeletal muscle and physical performance outcomes would further our knowledge of mechanisms related with proteostasis and healthy aging. Muscle biopsies were obtained from participants in the Study of Muscle, Mobility, and Aging (SOMMA). For 575 participants, RNA was sequenced and expression of 281 genes related to autophagy regulation, mitophagy, and mTOR/upstream pathways was determined. Associations between gene expression and outcomes including mitochondrial respiration in muscle fiber bundles (MAX OXPHOS), physical performance (VO 2 peak, 400 m walking speed, and leg power), and thigh muscle volume, were determined using negative binomial regression models. For autophagy, key transcriptional regulators including TFE3 and NFKB-related genes (RELA, RELB, and NFKB1) were negatively associated with outcomes. On the contrary, regulators of oxidative metabolism that also promote overall autophagy, mitophagy, and pexophagy (PPARGC1A, PPARA, and EPAS1) were positively associated with multiple outcomes. In line with this, several mitophagy, fusion, and fission-related genes (NIPSNAP2, DNM1L, and OPA1) were also positively associated with outcomes. For mTOR pathway and related genes, expression of WDR59 and WDR24, both subunits of GATOR2 complex (an indirect inhibitor of mTORC1), and PRKAG3, which is a regulatory subunit of AMPK, were negatively correlated with multiple outcomes. Our study identifies autophagy and selective autophagy such as mitophagy gene expression patterns in human skeletal muscle related to physical performance, muscle volume, and mitochondrial function in older persons which may lead to target identification to preserve mobility and independence., (© 2024 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Background: Whether circulating sex hormones modulate mortality and cardiovascular disease (CVD) risk in aging men is controversial., Purpose: To clarify associations of sex hormones with these outcomes., Data Sources: Systematic literature review to July 2019, with bridge searches to March 2024., Study Selection: Prospective cohort studies of community-dwelling men with sex steroids measured using mass spectrometry and at least 5 years of follow-up., Data Extraction: Independent variables were testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone (DHT), and estradiol concentrations. Primary outcomes were all-cause mortality, CVD death, and incident CVD events. Covariates included age, body mass index, marital status, alcohol consumption, smoking, physical activity, hypertension, diabetes, creatinine concentration, ratio of total to high-density lipoprotein cholesterol, and lipid medication use., Data Synthesis: Nine studies provided individual participant data (IPD) (255 830 participant-years). Eleven studies provided summary estimates ( n = 24 109). Two-stage random-effects IPD meta-analyses found that men with baseline testosterone concentrations below 7.4 nmol/L (<213 ng/dL), LH concentrations above 10 IU/L, or estradiol concentrations below 5.1 pmol/L had higher all-cause mortality, and those with testosterone concentrations below 5.3 nmol/L (<153 ng/dL) had higher CVD mortality risk. Lower SHBG concentration was associated with lower all-cause mortality (median for quintile 1 [Q1] vs. Q5, 20.6 vs. 68.3 nmol/L; adjusted hazard ratio [HR], 0.85 [95% CI, 0.77 to 0.95]) and lower CVD mortality (adjusted HR, 0.81 [CI, 0.65 to 1.00]). Men with lower baseline DHT concentrations had higher risk for all-cause mortality (median for Q1 vs. Q5, 0.69 vs. 2.45 nmol/L; adjusted HR, 1.19 [CI, 1.08 to 1.30]) and CVD mortality (adjusted HR, 1.29 [CI, 1.03 to 1.61]), and risk also increased with DHT concentrations above 2.45 nmol/L. Men with DHT concentrations below 0.59 nmol/L had increased risk for incident CVD events., Limitations: Observational study design, heterogeneity among studies, and imputation of missing data., Conclusion: Men with low testosterone, high LH, or very low estradiol concentrations had increased all-cause mortality. SHBG concentration was positively associated and DHT concentration was nonlinearly associated with all-cause and CVD mortality., Primary Funding Source: Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668)., Competing Interests: Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M23-2781.

Emerging studies highlight chrononutrition's impact on body composition through circadian clock entrainment, but its effect on older adults' muscle health remains largely overlooked. To determine the associations between chrononutrition behaviors and muscle health in older adults. Dietary data from 828 older adults (76 ± 5 years) recorded food/beverage amounts and their clock time over the past 24 h. Studied chrononutrition behaviors included: (1) The clock time of the first and last food/beverage intake; (2) Eating window (the time elapsed between the first and last intake); and (3) Eating frequency (Number of self-identified eating events logged with changed meal occasion and clock time). Muscle mass (D 3 -creatine), leg muscle volume (MRI), grip strength (hand-held dynamometer), and leg power (Keiser) were used as outcomes. We used linear regression to assess the relationships between chrononutrition and muscle health, adjusting for age, sex, race, marital status, education, study site, self-reported health, energy, protein, fiber intake, weight, height, and moderate-to-vigorous physical activity. Average eating window was 11 ± 2 h/day; first and last intake times were at 8:22 and 19:22, respectively. After multivariable adjustment, a longer eating window and a later last intake time were associated with greater muscle mass (β ± SE: 0.18 ± 0.09; 0.27 ± 0.11, respectively, p < 0.05). The longer eating window was also marginally associated with higher leg power (p = 0.058). An earlier intake time was associated with higher grip strength (-0.38 ± 0.15; p = 0.012). Chrononutrition behaviors, including longer eating window, later last intake time, and earlier first intake time were associated with better muscle mass and function in older adults., (© 2023 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Performance fatigability is typically experienced as insufficient energy to complete daily physical tasks, particularly with advancing age, often progressing toward dependency. Thus, understanding the etiology of performance fatigability, especially cellular-level biological mechanisms, may help to delay the onset of mobility disability. We hypothesized that skeletal muscle energetics may be important contributors to performance fatigability. Participants in the Study of Muscle, Mobility and Aging completed a usual-paced 400-m walk wearing a wrist-worn ActiGraph GT9X to derive the Pittsburgh Performance Fatigability Index (PPFI, higher scores = more severe fatigability) that quantifies percent decline in individual cadence-versus-time trajectory from their maximal cadence. Complex I&II-supported maximal oxidative phosphorylation (max OXPHOS) and complex I&II-supported electron transfer system (max ETS) were quantified ex vivo using high-resolution respirometry in permeabilized fiber bundles from vastus lateralis muscle biopsies. Maximal adenosine triphosphate production (ATP max ) was assessed in vivo by 31 P magnetic resonance spectroscopy. We conducted tobit regressions to examine associations of max OXPHOS, max ETS, and ATP max with PPFI, adjusting for technician/site, demographic characteristics, and total activity count over 7-day free-living among older adults (N = 795, 70-94 years, 58% women) with complete PPFI scores and ≥1 energetics measure. Median PPFI score was 1.4% [25th-75th percentile: 0%-2.9%]. After full adjustment, each 1 standard deviation lower max OXPHOS, max ETS, and ATP max were associated with 0.55 (95% CI: 0.26-0.84), 0.39 (95% CI: 0.09-0.70), and 0.54 (95% CI: 0.27-0.81) higher PPFI score, respectively. Our findings suggested that therapeutics targeting muscle energetics may potentially mitigate fatigability and lessen susceptibility to disability among older adults., (© 2023 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

With aging skeletal muscle fibers undergo repeating cycles of denervation and reinnervation. In approximately the 8th decade of life reinnervation no longer keeps pace, resulting in the accumulation of persistently denervated muscle fibers that in turn cause an acceleration of muscle dysfunction. The significance of denervation in important clinical outcomes with aging is poorly studied. The Study of Muscle, Mobility, and Aging (SOMMA) is a large cohort study with the primary objective to assess how aging muscle biology impacts clinically important traits. Using transcriptomics data from vastus lateralis muscle biopsies in 575 participants we have selected 49 denervation-responsive genes to provide insights to the burden of denervation in SOMMA, to test the hypothesis that greater expression of denervation-responsive genes negatively associates with SOMMA participant traits that included time to walk 400 meters, fitness (VO 2peak ), maximal mitochondrial respiration, muscle mass and volume, and leg muscle strength and power. Consistent with our hypothesis, increased transcript levels of: a calciumdependent intercellular adhesion glycoprotein (CDH15), acetylcholine receptor subunits (CHRNA1, CHRND, CHRNE), a glycoprotein promoting reinnervation (NCAM1), a transcription factor regulating aspects of muscle organization (RUNX1), and a sodium channel (SCN5A) were each negatively associated with at least 3 of these traits. VO 2peak and maximal respiration had the strongest negative associations with 15 and 19 denervation-responsive genes, respectively. In conclusion, the abundance of denervationresponsive gene transcripts is a significant determinant of muscle and mobility outcomes in aging humans, supporting the imperative to identify new treatment strategies to restore innervation in advanced age., (© 2024 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Background: Lower urinary tract symptoms (LUTS) in older men are associated with an increased risk of mobility limitations. Lower extremity muscle quality may represent a novel shared mechanism of both LUTS and mobility limitations., Methods: We evaluated associations of thigh skeletal muscle measures (strength, area, and specific force) with total LUTS severity (American Urologic Association Symptom Index; AUASI) and voiding and storage subscores among 352 men aged ≥60 years enrolled in the Baltimore Longitudinal Study of Aging. Thigh muscle strength (Nm) was defined as maximum concentric 30°/s knee extensor torque, area (cm2), and specific force (Nm/cm2) defined as strength/area. Associations with AUASI score were estimated using multivariable linear regression and linear mixed models., Results: Mean thigh muscle strength at baseline was 139.7Nm. In cross-sectional multivariable models, each 39Nm increment in thigh muscle strength and 0.28Nm/cm2 increment in specific force was associated with -1.17 point (95% CI: -1.93 to -.41) and -0.95 point (95% CI: -1.63 to -0.27) lower AUASI score, respectively. Similar associations were observed for voiding and storage subscores, although somewhat attenuated. In longitudinal analyses, baseline muscle measures were not associated with annual change in AUASI, and current changes in muscle measures and AUASI were unrelated., Conclusions: Cross-sectionally, higher thigh muscle strength and specific force were associated with decreased LUTS severity in older men. However, we did not observe concurrent worsening LUTS severity with declining thigh muscle strength, area, or specific force in longitudinal analyses., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objective: The aim of this study was to examine associations of ectopic adipose tissue (AT) with skeletal muscle (SM) mitochondrial bioenergetics in older adults., Methods: Cross-sectional data from 829 adults ≥70 years of age were used. Abdominal, subcutaneous, and visceral AT and thigh muscle fat infiltration (MFI) were quantified by magnetic resonance imaging. SM mitochondrial energetics were characterized in vivo ( 31 P-magnetic resonance spectroscopy; ATP max ) and ex vivo (high-resolution respirometry maximal oxidative phosphorylation [OXPHOS]). ActivPal was used to measure physical activity ([PA]; step count). Linear regression adjusted for covariates was applied, with sequential adjustment for BMI and PA., Results: Independent of BMI, total abdominal AT (standardized [Std.] β = -0.21; R 2  = 0.09) and visceral AT (Std. β = -0.16; R 2  = 0.09) were associated with ATP max (p < 0.01; n = 770) but not following adjustment for PA (p ≥ 0.05; n = 658). Visceral AT (Std. β = -0.16; R 2  = 0.25) and thigh MFI (Std. β = -0.11; R 2  = 0.24) were associated with carbohydrate-supported maximal OXPHOS independent of BMI and PA (p < 0.05; n = 609). Total abdominal AT (Std. β = -0.19; R 2  = 0.24) and visceral AT (Std. β = -0.17; R 2  = 0.24) were associated with fatty acid-supported maximal OXPHOS independent of BMI and PA (p < 0.05; n = 447)., Conclusions: Skeletal MFI and abdominal visceral, but not subcutaneous, AT are inversely associated with SM mitochondrial bioenergetics in older adults independent of BMI. Associations between ectopic AT and in vivo mitochondrial bioenergetics are attenuated by PA., (© 2024 The Obesity Society.)

Gene expression in skeletal muscle of older individuals may reflect compensatory adaptations in response to oxidative damage that preserve tissue integrity and maintain function. Identifying associations between oxidative stress response gene expression patterns and mitochondrial function, physical performance, and muscle mass in older individuals would further our knowledge of mechanisms related to managing molecular damage that may be targeted to preserve physical resilience. To characterize expression patterns of genes responsible for the oxidative stress response, RNA was extracted and sequenced from skeletal muscle biopsies collected from 575 participants (≥70 years old) from the Study of Muscle, Mobility, and Aging. Expression levels of 21 protein-coding RNAs related to the oxidative stress response were analyzed in relation to six phenotypic measures, including maximal mitochondrial respiration from muscle biopsies (Max OXPHOS), physical performance (VO 2 peak, 400-m walking speed, and leg strength), and muscle size (thigh muscle volume and whole-body D3Cr muscle mass). The mRNA level of the oxidative stress response genes most consistently associated across outcomes are preferentially expressed within the mitochondria. Higher expression of mRNAs that encode generally mitochondria located proteins SOD2, TRX2, PRX3, PRX5, and GRX2 were associated with higher levels of mitochondrial respiration and VO 2 peak. In addition, greater SOD2, PRX3, and GRX2 expression was associated with higher physical performance and muscle size. Identifying specific mechanisms associated with high functioning across multiple performance and physical domains may lead to targeted antioxidant interventions with greater impacts on mobility and independence., (© 2024 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Aims: To examine the associations of 1) absolute and normalized weakness cut-points, 2) collective weakness categories, and 3) changes in weakness status on future activities of daily living (ADL) limitations in older Americans., Methods: The analytic sample included 11,656 participants aged ≥65-years from the 2006-2018 waves of the Health and Retirement Study. ADL were self-reported. A handgrip dynamometer measured handgrip strength (HGS). Males were classified as weak if their HGS was <35.5-kg (absolute), <0.45-kg/kg (body mass normalized), or <1.05-kg/kg/m 2 (body mass index (BMI) normalized); females were considered weak if their HGS was <20.0-kg, <0.337-kg/kg, or <0.79-kg/kg/m 2 . Collective weakness categorized those below 1, 2, or all 3 absolute and normalized cut-points. These collective categories were also used to classify observed changes in weakness status over time (onset, persistent, progressive, recovery)., Results: Older Americans below absolute and normalized weakness cut-points had greater future ADL limitations odds: 1.34 (95% confidence interval (CI): 1.22-1.47) for absolute, 1.36 (CI: 1.24-1.50) for BMI normalized, and 1.56 (CI: 1.41-1.73) for body mass normalized. Persons below 1, 2, or 3 cut-points had 1.36 (CI: 1.19-1.55), 1.60 (CI: 1.41-1.80), and 1.70 (CI: 1.50-1.92) greater odds for future ADL limitations, respectively. Those in each changing weakness classification had greater future ADL limitation odds: 1.28 (CI: 1.01-1.62) for onset, 1.53 (CI: 1.22-1.92) for persistent, 1.72 (CI: 1.36-2.19) for progressive, and 1.34 (CI: 1.08-1.66) for recovery., Conclusions: The presence of weakness, regardless of cut-point and change in status over time, was associated with greater odds for future ADL limitations., Competing Interests: PMC is a consultant and owns stock in Myocorps for work unrelated to this research. In the past 5-years, BCC has received grant support from NMD Pharma, Myolex Inc., and Astella Pharma Global Development for contracted studies related to aging and muscle health. BCC is also co-founder with equity of OsteoDx Inc.

Background: Lower urinary tract symptoms (LUTS) and mobility limitations are bidirectionally associated among older adults, but the role of skeletal muscle remains unknown. We evaluated cross-sectional associations of muscle health and physical performance with LUTS., Methods: We used data from 377 women and 264 men aged >70 years in the Study of Muscle, Mobility and Aging (SOMMA). LUTS and urinary bother were assessed using the LURN Symptom Index-10 (SI-10; higher = worse symptoms). Muscle mass and volume were assessed using D3-creatine dilution (D3Cr) and magnetic resonance imaging. Grip strength and peak leg power assessed upper/lower extremity physical performance. 400-m walk, Short Physical Performance Battery (SPPB), and Four Square Step Test (FSST) assessed global physical performance. Mobility Assessment Tool-short form (MAT-sf) assessed self-reported mobility. We calculated Spearman correlation coefficients adjusted for age, body mass index, multimorbidity, and polypharmacy, chi-square tests, and Fisher's Z-test to compare correlations., Results: Among women, LURN SI-10 total scores were inversely correlated with FSST (rs = 0.11, p = .045), grip strength (rs = -0.15, p = .006), and MAT-sf (rs = -0.18, p = .001), but not other muscle and physical performance measures in multivariable models. LURN SI-10 was not associated with any of these measures among men. Forty-four percent of women in the lowest tertile of 400-m walk speed versus 24% in the highest tertile reported they were at least "somewhat bothered" by urinary symptoms (p < .001), whereas differences among men were not significant., Conclusions: Balance and grip strength were associated with LUTS severity in older women but not men. Associations with other muscle and physical performance measures varied by LUTS subtype but remained strongest among women., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Oxidative stress is considered a contributor to declining muscle function and mobility during aging; however, the underlying molecular mechanisms remain poorly described. We hypothesized that greater levels of cysteine (Cys) oxidation on muscle proteins are associated with decreased measures of mobility. Herein, we applied a novel redox proteomics approach to measure reversible protein Cys oxidation in vastus lateralis muscle biopsies collected from 56 subjects in the Study of Muscle, Mobility and Aging (SOMMA), a community-based cohort study of individuals aged 70 years and older. We tested whether levels of Cys oxidation on key muscle proteins involved in muscle structure and contraction were associated with muscle function (leg power and strength), walking speed, and fitness (VO 2 peak on cardiopulmonary exercise testing) using linear regression models adjusted for age, sex, and body weight. Higher oxidation levels of select nebulin Cys sites were associated with lower VO 2 peak, while greater oxidation of myomesin-1, myomesin-2, and nebulin Cys sites was associated with slower walking speed. Higher oxidation of Cys sites in key proteins such as myomesin-2, alpha-actinin-2, and skeletal muscle alpha-actin were associated with lower leg power and strength. We also observed an unexpected correlation (R = 0.48) between a higher oxidation level of eight Cys sites in alpha-actinin-3 and stronger leg power. Despite this observation, the results generally support the hypothesis that Cys oxidation of muscle proteins impairs muscle power and strength, walking speed, and cardiopulmonary fitness with aging., (© 2024 Battelle Memorial Institute and The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

The purpose of this article is to review steatosis and fibrosis of skeletal muscle, focusing on older adults. Although CT, MRI, and ultrasound are commonly used to image skeletal muscle and provide diagnoses for a variety of medical conditions, quantitative assessment of muscle steatosis and fibrosis is uncommon. This review provides radiologists with a broad perspective on muscle steatosis and fibrosis in older adults by considering the public health impact, biologic mechanisms, and evaluation with CT, MRI, and ultrasound. Promising directions in clinical research that entail artificial intelligence algorithms and the imaging assessment of biologic age are also reviewed. The imaging methods presented hold promise for improving the evaluation of common conditions affecting older adults, including sarcopenia, frailty, and cachexia.