Low skeletal muscle mass and treatment outcomes among adults with haematologic malignancies: A systematic review and meta-analysis.

BACKGROUND: Low skeletal muscle mass (LSMM) and/or, function associated with an increased risk of treatment-related toxicities and inferior overall survival (OS) among adults with solid malignancies. However, the association between LSMM and treatment-related toxicities among adults with haematologic malignancies remains unclear. METHODS: Using a pre-published protocol (CRD42020197814), we searched seven bibliographic databases from inception to 08/2021 for studies reporting the impact of LSMM among adults ≥18 years with a known haematologic malignancy. The primary outcome of interest was OS, and secondary outcomes included progression free survival (PFS) and non-relapse mortality (NRM). These effect sizes were quantified in terms of hazards ratio (HR) along with 95% confidence interval (CI) and pooled across studies using a DerSimonian-Laird random-effects model. Heterogeneity was assessed using the Cochran's Q and the I2 statistic. All hypothesis testing was two-sided with an alpha of 0.05. RESULTS: Of 3791 studies screened, we identified 20 studies involving 3468 patients with a mean age of 60 years; 44% were female and the most common malignancy was diffuse large B-cell lymphoma (42%). Most studies measured muscle mass using single slice computed tomography imaging at the L3 level. The presence of LSMM was associated with worse OS (pooled HR = 1.81, 95% CI = 1.48-2.22, P < 0.001) with moderate heterogeneity (Cochran's Q, I2 = 60.4%), PFS (pooled HR = 1.61, 95% CI = 1.28-2.02, P < 0.001) with moderate heterogeneity (Cochran's Q, I2 = 66.0%). Similarly, LSMM was associated with worse NRM (HR = 1.72, 95% CI = 1.34-2.22, P < 0.001) with little evidence of heterogeneity (Cochran's Q, I2 = 0.0%). CONCLUSIONS: LSMM is associated with worse survival outcomes among adults with haematologic malignancies. Further research into understanding the underlying mechanism of this association and mitigating the negative effects of LSMM among adults with haematologic malignancies is needed.

Delirium Due to Potentially Avoidable Hospitalizations Among Older Adults.

BACKGROUND: Delirium is a common complication during acute care hospitalizations in older adults. A substantial percentage of admissions are for ambulatory care-sensitive conditions (ACSCs) or potentially avoidable hospitalizations-conditions that might be treated early in the outpatient setting to prevent hospitalization and hospital complications. METHODS: This retrospective cross-sectional study examined rates of delirium among older adults hospitalized for ACSCs. Participants were 39 933 older adults ≥65 years of age admitted from January 1, 2015 to December 31, 2019 to general inpatient units and ICUs of a large Southeastern academic medical center. Delirium was defined as a score ≥ 2 on the Nursing Delirium Screening Scale or positive on the Confusion Assessment Method for the Intensive Care Unit during admission, and ACSCs were identified from the primary admission diagnosis using standardized definitions. Generalized linear mixed models were used to examine the association between ACSCs and delirium, compared with admissions for non-ACSC diagnoses, adjusting for covariates and repeated observations for individuals with multiple admissions. RESULTS: Delirium occurred in 15.6% of admissions for older adults. Rates were lower for ACSC admissions versus admissions for other conditions (13.9% vs 15.8%, p < .001). Older age and higher comorbidity were significant predictors of the development of delirium. CONCLUSIONS: Rates of delirium among older adults hospitalized for ACSCs were lower than rates for non-ACSC hospitalization but still substantial. Optimizing the treatment of ACSCs in the outpatient setting is an important goal not only for reducing hospitalizations but also for reducing risks for hospital-associated complications such as delirium.

Brief Report: Relationship Between Adiposity and Biomarkers of Aging and Frailty Among Adults Aging With HIV.

BACKGROUND: This study examined the relationships among adiposity, handgrip, physical function, inflammation (ie, senescence-associated secretory phenotype chemokines as biomarkers of aging and frailty), and sex hormones in aging people with HIV. METHODS: This cross-sectional exploratory study included 150 people with HIV aged ≥40 years (67.3% of participants were male). Our measures included (1) body mass index and waist circumference as measures of adiposity; (2) handgrip as a measure of muscle strength; (3) short physical performance battery as a measure of physical function; (4) interleukin-6, tumor necrosis factor alpha receptor II, high sensitivity C-reactive protein, C-X-C motif chemokine 10, and C-X3-C motif chemokine ligand 1 also known as fractalkine as senescence-associated secretory phenotype chemokines; and (5) free testosterone, estradiol, sex hormone-binding globulin, and dehydroepiandrosterone as sex hormones. Quantile regression analyses were used to identify relationships among inflammatory markers and hormones with age, adiposity, handgrip, and physical function. RESULTS: Overall, 74% (n = 111) of participants were classified as overweight or obese and 53.3% (n = 80) presented with abdominal obesity. After controlling for age and sex, body mass index was positively associated with estradiol (ß = 0.043, P < 0.01), and waist circumference was positively associated with high sensitivity C-reactive protein (ß = 2.151, P < 0.01). After controlling for sex, age was positively associated with C-X-C motif chemokine 10 (ß = 0.024, P = 0.03) and tumor necrosis factor alpha receptor II (ß = 2.205, P = 0.01). After controlling for age and sex, short physical performance battery was negatively associated with dehydroepiandrosterone (ß = -0.004, P = 0.01); no statistically significant associations were observed for handgrip. CONCLUSION: Adiposity levels and aging were associated with inflammation (ie, C-X-C motif chemokine 10, tumor necrosis factor alpha receptor II, and high sensitivity C-reactive protein) among people with HIV aged 40 years and older.

Greater socioenvironmental risk factors and higher chronic pain stage are associated with thinner bilateral temporal lobes.

INTRODUCTION: Previous research indicates ethnic/race group differences in pain and neurodegenerative diseases. Accounting for socioenvironmental factors reduces ethnic/race group differences in clinical and experimental pain. In the current study sample, we previously reported that in individuals with knee pain, ethnic/race group differences were observed in bilateral temporal lobe thickness, areas of the brain associated with risk for Alzheimer's disease, and related dementias. The purpose of the study was to determine if socioenvironmental factors reduce or account for previously observed ethnic/race group differences and explore if a combined effect of socioenvironmental risk and chronic pain severity on temporal lobe cortices is evident. METHODS: Consistent with the prior study, the sample was comprised of 147 adults (95 women, 52 men), 45-85 years of age, who self-identified as non-Hispanic Black (n = 72) and non-Hispanic White (n = 75), with knee pain with/at risk for osteoarthritis. Measures included demographics, health history, pain questionnaires, cognitive screening, body mass index, individual- and community-level socioenvironmental factors (education, income, household size, marital and insurance status, and area deprivation index), and brain imaging. We computed a summative socioenvironmental risk index. RESULTS: Regression analyses showed that with the inclusion of socioenvironmental factors, the model was significant (p < .001), and sociodemographic (ethnic/race) group differences were not significant (p = .118). Additionally, findings revealed an additive stress load pattern indicating thinner temporal lobe cortices with greater socioenvironmental risk and chronic pain severity (p = .048). IMPLICATIONS: Although individual socioenvironmental factors were not independent predictors, when collectively combined in models, ethnic/race group differences in bilateral temporal lobe structures were not replicated. Further, combined socioenvironmental risk factors and higher chronic pain severity were associated with thinner bilateral temporal lobes.

Physical activity is associated with adiposity in older adults with HIV in the modern HIV era.

OBJECTIVES: People with HIV (PWH) are aging and are experiencing higher rates of abdominal adiposity. Physical activity is an effective nonpharmacological strategy to reduce adiposity in the general aging population. Yet, the relationship between physical activity and adiposity in people with well controlled HIV is unclear. Our objective was to describe the association between objectively-measured physical activity and abdominal adiposity in PWH. METHODS: As part of the multisite, observational PROSPER-HIV study, virologically suppressed, adult PWH wore an Actigraph accelerometer for 7-10 days and completed duplicate waist and hip circumference measures. Demographic and medical characteristics were abstracted from the CFAR Network of Integrated Clinical Systems dataset. Descriptive statistics and multiple linear regressions were used to analyze the data. RESULTS: On average, our 419 PWH were 58 years of age [interquartile range (IQR): 50, 64], male (77%), Black (54%), and currently taking an integrase inhibitor (78%). PWH completed a mean of 7.06 (±2.74) days of total actigraphy wear time. They took an average of 4905 (3233, 7140) steps per day and engaged in 5.4 h of sedentary time per day. Controlling for age, sex, employment and integrase inhibitor use, the number of steps taken per day was associated with reduced abdominal adiposity ( F  = 3.27; P  < 0.001) and the hours of daily sedentary time was associated with increased abdominal adiposity ( F  = 3.24; P  < 0.001). CONCLUSIONS: Greater physical activity is associated with reduced abdominal adiposity in aging PWH. Future work should investigate how to tailor the amount, type and intensity of physical activity needed to reduce adiposity in PWH taking contemporary HIV medication. REGISTRATION NUMBER: NCT03790501.

Delirium Mediates Incidence of Hospital-Associated Disability Among Older Adults.

OBJECTIVE: To examine whether delirium predicts occurrence of hospital-associated disability (HAD), or functional decline after admission, among hospitalized older adults. DESIGN: Retrospective cross-sectional study. SETTING AND PARTICIPANTS: General inpatient (non-ICU) units of a large regional Southeastern US academic medical center, involving 33,111 older adults ≥65 years of age admitted from January 1, 2015, to December 31, 2019. METHODS: Delirium was defined as a score ≥2 on the Nursing Delirium Screening Scale (NuDESC) during hospital admission. HAD was defined as a decline on the Katz Activities of Daily Living (ADL) scale from hospital admission to discharge. Generalized linear mixed models were used to examine the association between delirium and HAD, adjusting for covariates and repeated observations with multiple admissions. We performed multivariate and mediation analyses to examine strength and direction of association between delirium and HAD. RESULTS: One-fifth (21.6%) of older adults developed HAD during hospitalization and experienced higher delirium rates compared to those not developing HAD (24.3% vs 14.3%, P < .001). Age, presence of delirium, Elixhauser Comorbidity Score, admission cognitive status, admission ADL function, and length of stay were associated (all P < .001) with incident HAD. Mediational analyses found 46.7% of the effect of dementia and 16.7% of the effect of comorbidity was due to delirium (P < .001). CONCLUSIONS AND IMPLICATIONS: Delirium significantly increased the likelihood of HAD within a multivariate predictor model that included comorbidity, demographics, and length of stay. For dementia and comorbidity, mediation analysis showed a significant portion of their effect attributable to delirium. Overall, these findings suggest that reducing delirium rates may diminish HAD rates.

Multiomics profiling of the impact of an angiotensin (1-7)-expressing probiotic combined with exercise training in aged male rats.

Angiotensin (1-7) [Ang (1-7)] is an active heptapeptide of the noncanonical arm of the renin-angiotensin system that modulates molecular signaling pathways associated with vascular and cellular inflammation, vasoconstriction, and fibrosis. Preclinical evidence suggests that Ang (1-7) is a promising therapeutic target that may ameliorate physical and cognitive function in late life. However, treatment pharmacodynamics limits its clinical applicability. Therefore, this study explored the underlying mechanisms altered by a genetically modified probiotic (GMP) that expresses Ang (1-7) combined with and without exercise training in an aging male rat model as a potential adjunct strategy to exercise training to counteract the decline of physical and cognitive function. We evaluated cross-tissue (prefrontal cortex, hippocampus, colon, liver, and skeletal muscle) multi-omics responses. After 12 wk of intervention, the 16S mRNA microbiome analysis revealed a main effect of probiotic treatment within- and between groups. The probiotic treatment enhanced α diversity (Inverse Simpson (F[2,56] = 4.44; P = 0.02); Shannon-Wiener (F[2,56] = 4.27; P = 0.02)) and ß-diversity (F[2,56] = 2.66; P = 0.01) among rats receiving our GMP. The analysis of microbes' composition revealed three genera altered by our GMP (Enterorhabdus, Muribaculaceae unclassified, and Faecalitalea). The mRNA multi-tissue data analysis showed that our combined intervention upregulated neuroremodeling pathways on prefrontal cortex (i.e., 140 genes), inflammation gene expression in the liver (i.e., 63 genes), and circadian rhythm signaling on skeletal muscle. Finally, the integrative network analysis detected different communities of tightly (|r| > 0.8 and P < 0.05) correlated metabolites, genera, and genes in these tissues.NEW & NOTEWORTHY This manuscript uses a multiomics approach (i.e., microbiome, metabolomics, and transcriptomics) to explore the underlying mechanisms driven by a genetically modified probiotic (GMP) designed to express angiotensin (1-7) combined with moderate exercise training in an aged male rat model. After 12 wk of intervention, our findings suggest that our GMP enhanced gut microbial diversity while exercise training altered the transcriptional response in relevant neuroremodeling genes, inflammation, and circadian rhythm signaling pathways in an aging animal model.

Hospital-associated disability due to avoidable hospitalizations among older adults.

BACKGROUND: Hospital-associated disability (HAD) is a common complication during the course of acute care hospitalizations in older adults. Many admissions are for ambulatory care sensitive conditions (ACSCs), considered potentially avoidable hospitalizations-conditions that might be treated in outpatient settings to prevent hospitalization and HAD. We compared the incidence of HAD between older adults hospitalized for ACSCs versus those hospitalized for other diagnoses. METHODS: We conducted a retrospective cohort study in inpatient (non-ICU) medical and surgical units of a large southeastern regional academic medical center. Participants were 38,960 older adults ≥ 65 years of age admitted from January 1, 2015, to December 31, 2019. The primary outcome was HAD, defined as decline on the Katz Activities of Daily Living (ADL) scale from hospital admission to discharge. We used generalized linear mixed models to examine differences in HAD between hospitalizations with a primary diagnosis for an ACSC using standard definitions versus primary diagnosis for other conditions, adjusting for covariates and repeated observations for individuals with multiple hospitalizations. RESULTS: We found that 10% of older adults were admitted for an ACSC, with rates of HAD in those admitted for ACSCs lower than those admitted for other conditions (16% vs. 20.7%, p < 0.001). Age, comorbidity, admission functional status, and admission cognitive impairment were significant predictors for development of HAD. ACSC admissions to medical and medical/surgical services had lower odds of HAD compared with admissions for other conditions, with no significant differences between ACSC and non-ACSC admissions to surgical services. CONCLUSIONS: Rates of HAD among older adults hospitalized for ACSCs are substantial, though lower than rates of HAD with hospitalization for other conditions, reflecting that acute care hospitalization is not a benign event in this population. Treatment of ACSCs in the outpatient setting could be an important component of efforts to reduce HAD.

Validity Properties of a Self-reported Modified Frailty Phenotype Among People With HIV in Clinical Care in the United States.

ABSTRACT: Modifications to Fried's frailty phenotype (FFP) are common. We evaluated a self-reported modified frailty phenotype (Mod-FP) used among people with HIV (PWH). Among 522 PWH engaged in two longitudinal studies, we assessed validity of the four-item Mod-FP compared with the five-item FFP. We compared the phenotypes via receiver operator characteristic curves, agreement in classifying frailty, and criterion validity via association with having experienced falls. Mod-FP classified 8% of PWH as frail, whereas FFP classified 9%. The area under the receiver operator characteristic curve for Mod-FP classifying frailty was 0.93 (95% CI = 0.91-0.96). We observed kappa ranging from 0.64 (unweighted) to 0.75 (weighted) for categorizing frailty status. Both definitions found frailty associated with a greater odds of experiencing a fall; FFP estimated a slightly greater magnitude (i.e., OR) for the association than Mod-FP. The Mod-FP has good performance in measuring frailty among PWH and is reasonable to use when the gold standards of observed assessments (i.e., weakness and slowness) are not feasible.

Inflammatory and Cardiovascular Correlates of Physical Activity and Sedentary Behavior in Older Adults Living With HIV.

BACKGROUND: Inflammation is an indicator of oxidative stress that may contribute to cardiovascular diseases in older people living with HIV (OPWH). Physical activity (PA) may reduce these biomarkers in OPWH, but little is known about the association of PA with inflammatory and cardiovascular biomarkers. We sought to examine the inflammatory and cardiovascular biomarker correlates of PA and sedentary behavior in OPWH. METHODS: We included 101 OPWH with complete assessments of PA, sedentary behavior, and biomarker data to examine the association between the volume of PA and inflammatory and cardiovascular biomarkers. RESULTS: In this cohort of OPWH (mean age 55.9 y), 68% were male and 83% were African American/Black. Among OPWH, greater volume of PA (ie, walking, moderate, vigorous, and/or total) was associated with lower systolic (P < .05) and diastolic blood pressure (P < .05), pulse pressure (P < .05), and tumor necrosis factor-alpha (P < .05). Greater duration of sitting was associated with greater triglycerides, interleukin-6, and tumor necrosis factor-alpha (P < .05). CONCLUSIONS: Although adherence to regular PA among OPWH is low and sedentary behavior is high, the associations between biomarkers and PA suggest a greater volume of PA could attenuate the inflammatory and cardiovascular derangements experienced by OPWH.

Angiotensin (1-7) Delivered Orally via Probiotic in Combination With Exercise: Sex-Dependent Influence on Health Span.

Age-related declines in physical and cognitive function can have tremendous, negative impacts on health span and quality of life. Therefore, we investigated the potential of utilizing a probiotic treatment to target the renin-angiotensin system (RAS) in conjunction with moderate exercise to ameliorate age-related declines in cognitive and physical function in aged rats. Herein we utilized a genetically modified angiotensin (1-7), which activates a "complementary" arm of the RAS through binding Mas (AT7) receptors. This process induces several beneficial physiologic effects, including decreased inflammation and enhanced physical/cognitive function. Thus, in this short research report, we suggest the efficacy of this Ang(1-7) releasing Lactobacillus paracasei (LPA) as either an alternative strategy to exercise, or more likely as an adjuvant to moderate exercise, for the prevention of both physical and cognitive decline especially in female rats.

The Association Between Objectively-Measured Physical Activity and Cognitive Functioning in Middle-Aged and Older People Living with HIV.

Middle-aged and older people living with HIV (PWH) are at higher risk for cognitive impairment and engage in lower levels of physical activity (PA) than seronegative counterparts. Research examining the association between objectively-measured PA and cognitive function in this population is scarce. This cross-sectional study examined the association between accelerometry-measured PA and cognitive functioning among 75 PWH (mean age 55.63). Light PA was the PA variable with the most consistent associations with cognition, with more minutes per week of light PA (performed in bouts of ≥ 10 min) being associated with better executive function, working memory/attention, and speed of processing performance, adjusted for age and current CD4 count. Findings suggest that although middle-aged and older PWH engage in more light than moderate-to-vigorous PA, light PA may be beneficial to cognition. Longitudinal studies are needed to understand PA dose-response associations with cognitive trajectories, cognitive domain specificity of PA effects, and underlying neural mechanisms of PA.

Effects of Broad-Spectrum Antibiotic Treatment or Germ-Free Status on Endurance Performance and Exercise Adaptations in Mice.

PURPOSE: Endurance exercise alters the gut microbiome independently of diet. The extent to which gut microbes are responsible for physiologic adaptations to exercise training is unknown. The purpose of these experiments was to determine the role of gut microbes in performance and muscle adaptation to 6 wk of voluntary wheel running (VWR) in mice. METHODS: We depleted microbes with broad-spectrum antibiotic (ABX) treatment and used germ-free (GF) mice to determine effects on adaptations to VWR. Male and female C57Bl/6 mice ( n = 56) were assigned to daily VWR or sedentary conditions. After the intervention, treadmill endurance and glucose tolerance were assessed, and gastrocnemius and soleus tissues were harvested and analyzed for citrate synthase (CS) enzyme activity and expression of exercise training-sensitive genes. RESULTS: ABX treatment and GF status resulted in VWR volumes ~22% and 26% lower than controls, respectively. Analysis of variance revealed that, although VWR increased treadmill endurance, ABX had no effect. GF status significantly reduced treadmill performance in trained GF mice after training. VWR increased gastrocnemius CS enzyme activity in all groups, and ABX and GF status did not reduce the VWR effect. VWR also increased muscle expression of PGC1a, but this was not affected by ABX treatment. CONCLUSIONS: ABX treatment and GF status reduced VWR behavior but did not affect VWR-induced adaptations in endurance capacity, CS activity, or expression of muscle metabolic genes. However, GF status reduced endurance capacity. These data indicated that reducing microbes in adulthood does not inhibit endurance training adaptations in C57Bl/6 mice, but that GF mice possess a reduced responsiveness to endurance exercise training, perhaps because of a developmental defect associated with lack of microbes from birth.

Prospective Association of Daily Steps With Cardiovascular Disease: A Harmonized Meta-Analysis.

BACKGROUND: Taking fewer than the widely promoted "10 000 steps per day" has recently been associated with lower risk of all-cause mortality. The relationship of steps and cardiovascular disease (CVD) risk remains poorly described. A meta-analysis examining the dose-response relationship between steps per day and CVD can help inform clinical and public health guidelines. METHODS: Eight prospective studies (20 152 adults [ie, ≥18 years of age]) were included with device-measured steps and participants followed for CVD events. Studies quantified steps per day and CVD events were defined as fatal and nonfatal coronary heart disease, stroke, and heart failure. Cox proportional hazards regression analyses were completed using study-specific quartiles and hazard ratios (HR) and 95% CI were meta-analyzed with inverse-variance-weighted random effects models. RESULTS: The mean age of participants was 63.2±12.4 years and 52% were women. The mean follow-up was 6.2 years (123 209 person-years), with a total of 1523 CVD events (12.4 per 1000 participant-years) reported. There was a significant difference in the association of steps per day and CVD between older (ie, ≥60 years of age) and younger adults (ie, <60 years of age). For older adults, the HR for quartile 2 was 0.80 (95% CI, 0.69 to 0.93), 0.62 for quartile 3 (95% CI, 0.52 to 0.74), and 0.51 for quartile 4 (95% CI, 0.41 to 0.63) compared with the lowest quartile. For younger adults, the HR for quartile 2 was 0.79 (95% CI, 0.46 to 1.35), 0.90 for quartile 3 (95% CI, 0.64 to 1.25), and 0.95 for quartile 4 (95% CI, 0.61 to 1.48) compared with the lowest quartile. Restricted cubic splines demonstrated a nonlinear association whereby more steps were associated with decreased risk of CVD among older adults. CONCLUSIONS: For older adults, taking more daily steps was associated with a progressively decreased risk of CVD. Monitoring and promoting steps per day is a simple metric for clinician-patient communication and population health to reduce the risk of CVD.

Cardiometabolic Diseases and Quality-of-Life Outcomes in Adults With HIV in the Deep South: A Cross-sectional Study.

ABSTRACT: The role of cardiometabolic diseases (CMDs) on physical health-related quality of life (P-HRQoL) and quality of sleep was examined among 261 PLWH ≥40 years, recruited from a university-affiliated HIV clinic in the Deep U.S. South. Using a cross-sectional study design, participants completed the Medical Outcomes Study HIV Health Survey (MOS-HIV; P-HRQoL) and Pittsburgh Sleep Quality Index. The overall prevalence of self-reporting ≥1 CMD was 64.4%. P-HRQoL scores were lower in PLWH with ≥1 CMD compared with those with no CMDs (45.53 ± 11.54 vs. 49.67 ± 10.77, p <.01). Poor sleep quality was higher among participants with ≥1 CMD compared with those with no CMDs (9.28 ± 4.42 vs. 7.26 ± 4.17, p <.01). Each additional CMD resulted in a 1.83-point decrease in P-HRQoL and 0.74-point increase in poor sleep quality scores. Interventions that focus on targeting these quality-of-life domains in PLWH with CMDs are needed.

Understanding heterogeneity of responses to, and optimizing clinical efficacy of, exercise training in older adults: NIH NIA Workshop summary.

Exercise is a cornerstone of preventive medicine and a promising strategy to intervene on the biology of aging. Variation in the response to exercise is a widely accepted concept that dates back to the 1980s with classic genetic studies identifying sequence variations as modifiers of the VO2max response to training. Since that time, the literature of exercise response variance has been populated with retrospective analyses of existing datasets that are limited by a lack of statistical power from technical error of the measurements and small sample sizes, as well as diffuse outcomes, very few of which have included older adults. Prospective studies that are appropriately designed to interrogate exercise response variation in key outcomes identified a priori and inclusive of individuals over the age of 70 are long overdue. Understanding the underlying intrinsic (e.g., genetics and epigenetics) and extrinsic (e.g., medication use, diet, chronic disease) factors that determine robust versus poor responses to various exercise factors will be used to improve exercise prescription to target the pillars of aging and optimize the clinical efficacy of exercise training in older adults. This review summarizes the proceedings of the NIA-sponsored workshop entitled, "Understanding Heterogeneity of Responses to, and Optimizing Clinical Efficacy of, Exercise Training in Older Adults" and highlights the importance and current state of exercise response variation research, particularly in older adults, prevailing challenges, and future directions.

Cross-Sectional Brain-Predicted Age Differences in Community-Dwelling Middle-Aged and Older Adults with High Impact Knee Pain.

Purpose: Knee OA-related pain varies in impact across individuals and may relate to central nervous system alterations like accelerated brain aging processes. We previously reported that older adults with chronic musculoskeletal pain had a significantly greater brain-predicted age, compared to pain-free controls, indicating an "older" appearing brain. Yet this association is not well understood. This cross-sectional study examines brain-predicted age differences associated with chronic knee osteoarthritis pain, in a larger, more demographically diverse sample with consideration for pain's impact. Patients and Methods: Participants (mean age = 57.8 ± 8.0 years) with/without knee OA-related pain were classified according to pain's impact on daily function (ie, impact): low-impact (n=111), and high-impact (n=60) pain, and pain-free controls (n=31). Participants completed demographic, pain, and psychosocial assessments, and T1-weighted magnetic resonance imaging. Brain-predicted age difference (brain-PAD) was compared across groups using analysis of covariance. Partial correlations examined associations of brain-PAD with pain and psychosocial variables. Results: Individuals with high-impact chronic knee pain had significantly "older" brains for their age compared to individuals with low-impact knee pain (p < 0.05). Brain-PAD was also significantly associated with clinical pain, negative affect, passive coping, and pain catastrophizing (p's<0.05). Conclusion: Our findings suggest that high impact chronic knee pain is associated with an older appearing brain on MRI. Future studies are needed to determine the impact of pain-related interference and pain management on somatosensory processing and brain aging biomarkers for high-risk populations and effective intervention strategies.

Twelve Months of Time-Restricted Feeding Improves Cognition and Alters Microbiome Composition Independent of Macronutrient Composition.

Declining health, gut dysbiosis, and cognitive impairments are hallmarks of advanced age. While caloric restriction is known to robustly extend the healthspan and alter gut microbiome composition, it is difficult maintain. Time-restricted feeding or changes in dietary macronutrient composition could be feasible alternatives for enhancing late life cognitive and physical health that are easier to comply with for extended periods of time. To investigate this possibility, 8-month-old rats were placed on time-restricted feeding with a ketogenic or micronutrient- and calorically matched control diet for 13 months. A third group of rats was permitted to eat standard chow ad libitum during this time. At 22 months, all rats were tested on a biconditional association task and fecal samples were collected for microbiome composition analysis. Regardless of dietary composition, time-restricted-fed rats had better cognitive performance than ad libitum-fed rats. This observation could not be accounted for by differences in motivation, procedural or sensorimotor impairments. Additionally, there were significant differences in gut microbiome diversity and composition between all diet conditions. Allobaculum abundance was associated with cognitive task performance, indicating a link between gut health and cognitive outcomes in aged subjects. Overall, time restricted feeding had the largest influence on cognitive performance in aged rats.

Preserving independence among under-resourced older adults in the Southeastern United States: existing barriers and potential strategies for research.

Disability prevention and preservation of independence is crucial for successful aging of older adults. To date, relatively little is known regarding disparities in independent aging in a disadvantaged older adult population despite widely recognized health disparities reported in other populations and disciplines. In the U.S., the Southeastern region also known as "the Deep South", is an economically and culturally unique region ravaged by pervasive health disparities - thus it is critical to evaluate barriers to independent aging in this region along with strategies to overcome these barriers. The objective of this narrative review is to highlight unique barriers to independent aging in the Deep South and to acknowledge gaps and potential strategies and opportunities to fill these gaps. We have synthesized findings of literature retrieved from searches of computerized databases and authoritative texts. Ultimately, this review aims to facilitate discussion and future research that will help to address the unique challenges to the preservation of independence among older adults in the Deep South region.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions.

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.