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Background: Growth differentiation factor 15 (GDF-15) is a member of the TGFß superfamily secreted by many cell types and found at higher blood concentrations as chronological age increases (1). Given the emergence of GDF-15 as a key protein associated with aging, it is important to understand the multitude of conditions with which circulating GDF-15 is associated. Methods: We pooled data from 1,174 randomly selected Health ABC Study (Health ABC) participants and 1,503 Cardiovascular Health Study (CHS) participants to evaluate the risk of various conditions and age-related outcomes across levels of GDF-15. The primary outcomes were (1) risk of mobility disability and falls; (2) impaired cognitive function; (3) and increased risk of cardiovascular disease and total mortality. Results: The pooled study cohort had a mean age of 75.4 +/-4.4 years. Using a Bonferroni-corrected threshold, our analyses show that high levels of GDF-15 were associated with a higher risk of severe mobility disability (HR: 2.13 [1.64, 2.77]), coronary heart disease (HR: 1.47 [1.17, 1.83]), atherosclerotic cardiovascular disease (HR: 1.56 [1.22, 1.98]), heart failure (HR: 2.09 [1.66, 2.64]), and mortality (HR: 1.81 [1.53, 2.15]) when comparing the highest and lowest quartiles. For CHS participants, analysis of extreme quartiles in fully adjusted models revealed a 3.5-fold higher risk of dementia (HR: 3.50 [1.97, 6.22]). Conclusions: GDF-15 is associated with several age-related outcomes and diseases, including mobility disability, impaired physical and cognitive performance, dementia, cardiovascular disease, and mortality. Each of these findings demonstrates the importance of GDF-15 as a potential biomarker for many aging-related conditions.
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BACKGROUND: This study compared the mortality risk of long-lived siblings with the U.S. population average and their spouse controls, and investigated the leading causes of death and the familial effect in death pattern. METHODS: In the Long Life Family Study (LLFS), 1,264 proband siblings (Mean age 90.1, SD 6.4) and 172 spouses (83.8, 7.2) from 511 U.S.-based families were recruited and followed over 12 years. Their survival function was compared with a birth cohort-, baseline age-, sex-, and race-matched pseudo sample from U.S. census data. To examine underlying and contributing causes, we examined in detail 338 deaths with complete death adjudication at the University of Pittsburgh Field Center through the year 2018. A familial effect on survival and death pattern was examined using mixed effect models. RESULTS: The LLFS siblings had better survival than the matched U.S. population average. They also had slightly but not significantly better survival than their spouses' (HR=1.18 [95%CI 0.94-1.49]) after adjusting for age and sex. Age at death ranged from 75-104 years, mean 91.4. The leading causes of death were cardiovascular disease (33.1%), dementia (22.2%), and cancer (10.7%). Mixed effect model shows a significant random effect of family in survival, with adjustment of baseline age and sex. There was no significant familial effect in the underlying cause of death or conditions directly contributing to death among siblings recruited by the University of Pittsburgh Field Center. CONCLUSION: Our findings demonstrate a higher survival in the LLFS siblings than the U.S. census data, with a familial component of survival. We did not find significant correspondence in causes of death between siblings within families.
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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.
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Metabolismo Energético , Fadiga , Consumo de Oxigênio , Velocidade de Caminhada , Caminhada , Humanos , Masculino , Velocidade de Caminhada/fisiologia , Feminino , Idoso , Metabolismo Energético/fisiologia , Consumo de Oxigênio/fisiologia , Fadiga/fisiopatologia , Caminhada/fisiologia , Teste de Esforço/métodos , Envelhecimento/fisiologia , Pessoa de Meia-Idade , Idoso de 80 Anos ou maisRESUMO
Greater perceived physical fatigability and lower skeletal muscle energetics are 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 in 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.
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Background and Objectives: Fall injuries are prevalent in older adults, yet whether higher spending occurs after nonfracture (NFFI) and fracture is unknown. We examined whether incident fall injuries, including NFFI and fractures, were associated with higher Medicare spending in 12 months after incident events in older adults. Research Design and Methods: The Health, Aging, and Body Composition Study included 1 595 community-dwelling adults (53% women, 37% Black; 76.7â ±â 2.9 years) with linked Medicare Fee-For-Service (FFS) claims at 2000/01 exam. Incident outpatient and inpatient fall injuries (Nâ =â 448) from 2000/01 exam to December 31, 2008 were identified using the first claim with a nonfracture injury diagnosis code with a fall E-code, or a fracture diagnosis code with/without an E-code. Up to 3 participants without fall injuries (Nâ =â 1 147) were matched on nonfall events to 448 participants in the fall injury month. We calculated the change in monthly FFS spending in 12 months before versus after index events in both groups. Generalized linear regression with centered outcomes and gamma distributions examined the association of prepost expenditure changes with fall injuries (including NFFI and fractures) adjusting for related covariates. Results: Monthly spending increased after versus before fall injuries (USD$2 261 vs $981), nonfracture (Nâ =â 105; USD$2 083 vs $1 277), and fracture (Nâ =â 343; USD$2 315 vs $890) injuries (all pâ <â .0001). However, after adjusting for covariates in final models, fall injuries were not significantly associated with larger increases in spending/month versus nonfall events (differential increase: USD$399.58 [95% CI: -USD$44.95 to $844.11]). Fracture prepost change in monthly spending was similar versus NFFI (differential increase: USD$471.93 [95% CI: -USD$21.17 to $965.02]). Discussion and Implications: Although substantial increases occurred after injuries, with fracture and NFFI increasing similarly, changes in monthly spending after fall injury were not different compared to nonfall events. Our results contribute to the understanding of subsequent spending after fall injury that may inform further research on fall injury-related health care spending.
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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 (VO2peak), 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. VO2peak 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.
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Envelhecimento , Músculo Esquelético , Humanos , Envelhecimento/genética , Masculino , Músculo Esquelético/metabolismo , Músculo Esquelético/inervação , Idoso , Feminino , Pessoa de Meia-Idade , Estudos de Coortes , AdultoRESUMO
BACKGROUND: Air pollution is a modifiable risk factor for dementia. Yet, studies on specific sources of air pollution (i.e., toxic chemical emissions from industrial facilities) and dementia risk are scarce. We examined associations between toxicity-weighted concentrations of industrial pollution and dementia outcomes among a large, multi-site cohort of older adults. METHODS: Participants (n = 2770) were ≥ 65 years old (Mean = 75.3, SD = 5.1 years) from the Cardiovascular Health Cognition Study (1992-1999). Toxicity-weighted concentrations were estimated using the Risk Screening Environmental Indicator (RSEI) model which incorporates total reported chemical emissions with toxicity, fate, and transport models. Estimates were aggregated to participants' baseline census tract, averaged across 1988-1992, and log2-transformed. Dementia status was clinically adjudicated in 1998-1999 and categorized by subtype (Alzheimer's, vascular, mixed). We assessed whether RSEI-estimated toxicity-weighted concentrations were associated with 1) odds of prevalent dementia and 2) incident dementia risk by subtype. RESULTS: After adjusting for individual and census-tract level covariates, a doubling in toxicity-weighted concentrations was associated with 9 % higher odds of prevalent dementia (OR = 1.09, 95 % CI: 1.00, 1.19). In discrete-time survival models, each doubling in toxicity-weighted concentrations was associated with a 16 % greater hazard of vascular dementia (HR = 1.16, 95 % CI: 1.01, 1.34) but was not significantly associated with all-cause, Alzheimer's disease, or mixed dementia (p's > 0.05). DISCUSSION: Living in regions with higher toxicity-weighted concentrations was associated with higher odds of prevalent dementia and a higher risk of incident vascular dementia in this large, community-based cohort of older adults. These findings support the need for additional studies to examine whether toxic chemical emissions from industrial and federal facilities may be a modifiable target for dementia prevention.
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Poluentes Atmosféricos , Poluição do Ar , Demência , Exposição Ambiental , Humanos , Demência/epidemiologia , Idoso , Masculino , Feminino , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Fatores de Risco , Idoso de 80 Anos ou maisRESUMO
Experiencing decline in both cognition and mobility is associated with a substantially higher dementia risk than cognitive decline only. Metabolites associated with both cognitive and mobility declines may be early predictors of dementia and reveal specific pathways to dementia. We analyzed data from 2450 participants initially free of dementia who had 613 metabolites measured in plasma in 1998-1999 (mean age = 75.2 ± 2.9 years old, 37.8% Black, 50% women) from the Health, Aging and Body Composition study. Dementia diagnosis was determined by race-specific decline in 3MS scores, medication use, and hospital records through 2014. Cognition and mobility were repeatedly measured using 3MS and a 20-m walking test up to 10 years, respectively. We examined metabolite associations with changes in 3MS (n = 2046) and gait speed (n = 2019) using multivariable linear regression adjusted for age, sex, race, and baseline performance and examined metabolite associations with dementia risk using Cox regression. During a mean follow-up of 9.3 years, 534 (21.8%) participants developed dementia. On average, 3MS declined 0.47/year and gait declined 0.04 m/sec/year. After covariate adjustment, 75 metabolites were associated with cognitive decline, and 111 metabolites were associated with gait decline (FDR-adjusted p < 0.05). Twenty-six metabolites were associated with both cognitive and gait declines. Eighteen of 26 metabolites were associated with dementia risk (p < 0.05), notably amino acids, glycerophospholipids (lysoPCs, PCs, PEs), and sphingolipids. Results remained similar after adjusting for cardiovascular disease or apolipoprotein E É4 carrier status. During aging, metabolomic profiles of cognitive decline and mobility decline show distinct and shared signatures. Shared metabolomic profiles suggest that inflammation and deficits in mitochondria and the urea cycle in addition to the central nervous system may play key roles in both cognitive and mobility declines and predict dementia. Future studies are warranted to investigate longitudinal metabolite changes and metabolomic markers with dementia pathologies.
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Disfunção Cognitiva , Demência , Humanos , Feminino , Masculino , Idoso , Demência/sangue , Disfunção Cognitiva/sangue , Limitação da Mobilidade , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Metabolômica , Metaboloma , Fatores de RiscoRESUMO
BACKGROUND: Low grip strength and gait speed are associated with mortality. However, investigation of the additional mortality risk explained by these measures, over and above other factors, is limited. AIM: We examined whether grip strength and gait speed improve discriminative capacity for mortality over and above more readily obtainable clinical risk factors. METHODS: Participants from the Health, Aging and Body Composition Study, Osteoporotic Fractures in Men Study, and the Hertfordshire Cohort Study were analysed. Appendicular lean mass (ALM) was ascertained using DXA; muscle strength by grip dynamometry; and usual gait speed over 2.4-6 m. Verified deaths were recorded. Associations between sarcopenia components and mortality were examined using Cox regression with cohort as a random effect; discriminative capacity was assessed using Harrell's Concordance Index (C-index). RESULTS: Mean (SD) age of participants (n = 8362) was 73.8(5.1) years; 5231(62.6%) died during a median follow-up time of 13.3 years. Grip strength (hazard ratio (95% CI) per SD decrease: 1.14 (1.10,1.19)) and gait speed (1.21 (1.17,1.26)), but not ALM index (1.01 (0.95,1.06)), were associated with mortality in mutually-adjusted models after accounting for age, sex, BMI, smoking status, alcohol consumption, physical activity, ethnicity, education, history of fractures and falls, femoral neck bone mineral density (BMD), self-rated health, cognitive function and number of comorbidities. However, a model containing only age and sex as exposures gave a C-index (95% CI) of 0.65(0.64,0.66), which only increased to 0.67(0.67,0.68) after inclusion of grip strength and gait speed. CONCLUSIONS: Grip strength and gait speed may generate only modest adjunctive risk information for mortality compared with other more readily obtainable risk factors.
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Força da Mão , Sarcopenia , Velocidade de Caminhada , Humanos , Sarcopenia/mortalidade , Sarcopenia/fisiopatologia , Masculino , Idoso , Força da Mão/fisiologia , Feminino , Velocidade de Caminhada/fisiologia , Estudos de Coortes , Fatores de Risco , Valor Preditivo dos Testes , Idoso de 80 Anos ou mais , MortalidadeRESUMO
Background: Better physical robustness and resilience of long-lived siblings compared to sporadic long-livers has been demonstrated in several studies. However, it is unknown whether long-lived siblings also end their lives better. Objective: To investigate end-of-life (EoL) events (dementia diagnosis, medication, hospitalizations in the last 5 years of life), causes of death, and location of death in long-lived siblings compared to matched sporadic long-livers from the Danish population. Methods: Long-lived siblings were identified through three nationwide Danish studies in which the inclusion criteria varied, but 99.5% of the families had at least two siblings surviving to age 90â+â. Those who died between 2006 and 2018 were included, and randomly matched with sex, year-of-birth and age-at-death controls (i.e., sporadic long-lived controls) from the Danish population. Results: A total of 5,262 long-lived individuals were included (1,754 long-lived siblings, 3,508 controls; 63% women; median age at death 96.1). Long-lived siblings had a significantly lower risk of being diagnosed with dementia in the last years of life (pâ=â0.027). There was no significant difference regarding the number of prescribed drugs, hospital stays, days in hospital, and location of death. Compared to controls, long-lived siblings presented a lower risk of dying from dementia (pâ=â0.020) and ill-defined conditions (pâ=â0.030). Conclusions: In many aspects long-lived siblings end their lives similar to sporadic long-livers, with the important exception of lower dementia risk during the last 5 years of life. These results suggest that long-lived siblings are excellent candidates for identifying environmental and genetic protective factors of dementia.
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Causas de Morte , Demência , Irmãos , Humanos , Dinamarca/epidemiologia , Masculino , Feminino , Demência/epidemiologia , Demência/mortalidade , Idoso de 80 Anos ou mais , Longevidade , IdosoRESUMO
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 (31P-magnetic resonance spectroscopy; ATPmax) 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.] ß = -0.21; R2 = 0.09) and visceral AT (Std. ß = -0.16; R2 = 0.09) were associated with ATPmax (p < 0.01; n = 770) but not following adjustment for PA (p ≥ 0.05; n = 658). Visceral AT (Std. ß = -0.16; R2 = 0.25) and thigh MFI (Std. ß = -0.11; R2 = 0.24) were associated with carbohydrate-supported maximal OXPHOS independent of BMI and PA (p < 0.05; n = 609). Total abdominal AT (Std. ß = -0.19; R2 = 0.24) and visceral AT (Std. ß = -0.17; R2 = 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.
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Índice de Massa Corporal , Metabolismo Energético , Músculo Esquelético , Humanos , Feminino , Idoso , Masculino , Metabolismo Energético/fisiologia , Estudos Transversais , Músculo Esquelético/metabolismo , Fosforilação Oxidativa , Imageamento por Ressonância Magnética , Tecido Adiposo/metabolismo , Distribuição da Gordura Corporal , Mitocôndrias Musculares/metabolismo , Gordura Intra-Abdominal/metabolismo , Idoso de 80 Anos ou maisRESUMO
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 (VO2 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.
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Envelhecimento , Autofagia , Músculo Esquelético , Humanos , Músculo Esquelético/metabolismo , Autofagia/genética , Idoso , Masculino , Feminino , Envelhecimento/genética , Envelhecimento/metabolismo , Desempenho Físico Funcional , Mitocôndrias/metabolismo , Mitocôndrias/genética , Idoso de 80 Anos ou maisRESUMO
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.
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Envelhecimento , Metabolismo Energético , Mitocôndrias Musculares , Multimorbidade , Humanos , Feminino , Idoso , Masculino , Metabolismo Energético/fisiologia , Mitocôndrias Musculares/metabolismo , Envelhecimento/metabolismo , Envelhecimento/fisiologia , Idoso de 80 Anos ou mais , Músculo Esquelético/metabolismoRESUMO
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.
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Aptidão Cardiorrespiratória , Teste de Esforço , Consumo de Oxigênio , Humanos , Idoso , Teste de Esforço/métodos , Aptidão Cardiorrespiratória/fisiologia , Consumo de Oxigênio/fisiologia , Masculino , Feminino , Estudos Prospectivos , Reprodutibilidade dos Testes , Frequência Cardíaca/fisiologia , Estudos de Viabilidade , Idoso de 80 Anos ou maisRESUMO
Social stress experienced in childhood is associated with adverse health later in life. Mitochondrial function has been implicated as a mechanism for how stressful life events "get under the skin" to influence physical well-being. Using data from the Study of Muscle, Mobility, and Aging (n = 879, 59% women), linear models examined whether adverse childhood events (i.e., physical abuse) were associated with two measures of skeletal muscle mitochondrial energetics in older adults: (i) maximal adenosine triphosphate production (ATPmax) and (ii) maximal state 3 respiration (Max OXPHOS). Forty-five percent of the sample reported experiencing one or more adverse childhood events. After adjustment, each additional event was associated with -0.08 SD (95% confidence interval = -0.13, -0.02) lower ATPmax. No association was observed with Max OXPHOS. Adverse childhood events are associated with lower ATP production in later life. Findings indicate that mitochondrial function may be a mechanism for understanding how early social stress influences health in later life.
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Músculo Esquelético , Fenômenos Fisiológicos Musculoesqueléticos , Feminino , Humanos , Idoso , Masculino , Trifosfato de Adenosina , Envelhecimento , MitocôndriasRESUMO
BACKGROUND: Aging increases fracture risk through bone loss and microarchitecture deterioration due to an age-related imbalance in bone resorption and formation during bone remodelling. We examined the associations between levels of phosphate, calcium, and alkaline phosphatase, and fracture risk in initially-healthy older individuals. METHODS: A post-hoc analysis of the Aspirin in Reducing Events in the Elderly (ASPREE) trial recruited 16,703 Australian participants aged ≥70 years and 2,411 US participants aged ≥65 years. Analyses were conducted on ASPREE-Fracture substudy participants from Australia with serum calcium, phosphate, and alkaline phosphatase measurement. Fracture data were collected post-randomization. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CIs). Phosphate, calcium, and alkaline phosphatase were analysed in deciles (D1-D10), with deciles 4-7 (31-70%) as the reference category. Restricted cubic spline curves were used to identify nonlinear associations. RESULTS: Of the 9915 participants, 907 (9·2%) persons had incident fractures recorded over 3·9 (SD 1·4) years. In the fully adjusted model, males in the top decile (D10) of phosphate had 78% higher risk of incident fracture (HR 1·78, 95% CI 1·25-2·54). No such association was observed for females (HR 1·09, 95% CI 0·83-1·44). The population attributable fraction in men within the D10 phosphate category is 6·9%. CONCLUSION: This result confirms that, high-normal serum phosphate levels are associated with increased fracture risk in older men.
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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 â¼20-70% 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.
Assuntos
Aptidão Cardiorrespiratória , Diabetes Mellitus , Mitocôndrias Musculares , Velocidade de Caminhada , Humanos , Idoso , Masculino , Feminino , Velocidade de Caminhada/fisiologia , Aptidão Cardiorrespiratória/fisiologia , Mitocôndrias Musculares/metabolismo , Diabetes Mellitus/metabolismo , Diabetes Mellitus/fisiopatologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatologia , Pessoa de Meia-IdadeRESUMO
The identification of protein targets that exhibit anti-aging clinical potential could inform interventions to lengthen the human health span. Most previous proteomics research has been focused on chronological age instead of longevity. We leveraged two large population-based prospective cohorts with long follow-ups to evaluate the proteomic signature of longevity defined by survival to 90 years of age. Plasma proteomics was measured using a SOMAscan assay in 3067 participants from the Cardiovascular Health Study (discovery cohort) and 4690 participants from the Age Gene/Environment Susceptibility-Reykjavik Study (replication cohort). Logistic regression identified 211 significant proteins in the CHS cohort using a Bonferroni-adjusted threshold, of which 168 were available in the replication cohort and 105 were replicated (corrected p value <0.05). The most significant proteins were GDF-15 and N-terminal pro-BNP in both cohorts. A parsimonious protein-based prediction model was built using 33 proteins selected by LASSO with 10-fold cross-validation and validated using 27 available proteins in the validation cohort. This protein model outperformed a basic model using traditional factors (demographics, height, weight, and smoking) by improving the AUC from 0.658 to 0.748 in the discovery cohort and from 0.755 to 0.802 in the validation cohort. We also found that the associations of 169 out of 211 proteins were partially mediated by physical and/or cognitive function. These findings could contribute to the identification of biomarkers and pathways of aging and potential therapeutic targets to delay aging and age-related diseases.
Assuntos
Longevidade , Proteômica , Humanos , Longevidade/fisiologia , Proteômica/métodos , Feminino , Masculino , Idoso , Idoso de 80 Anos ou mais , Pessoa de Meia-Idade , Estudos de Coortes , Biomarcadores/sangue , Envelhecimento/sangueRESUMO
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.
Assuntos
Ritmo Circadiano , Descanso , Masculino , Humanos , Feminino , Idoso , Estudos Transversais , Descanso/fisiologia , Ritmo Circadiano/fisiologia , Envelhecimento/fisiologia , Actigrafia , Músculos , Sono/fisiologiaRESUMO
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.