Relative contributions of adiposity and muscularity to physical function in community-dwelling older adults

Fatty infiltration in the musculoskeletal system: pathological mechanisms and clinical implications

Fatty infiltration denotes the anomalous accrual of adipocytes in non-adipose tissue, thereby generating toxic substances with the capacity to impede the ordinary physiological functions of various organs. With aging, the musculoskeletal system undergoes pronounced degenerative alterations, prompting heightened scrutiny regarding the contributory role of fatty infiltration in its pathophysiology. Several studies have demonstrated that fatty infiltration affects the normal metabolism of the musculoskeletal system, leading to substantial tissue damage. Nevertheless, a definitive and universally accepted generalization concerning the comprehensive effects of fatty infiltration on the musculoskeletal system remains elusive. As a result, this review summarizes the characteristics of different types of adipose tissue, the pathological mechanisms associated with fatty infiltration in bone, muscle, and the entirety of the musculoskeletal system, examines relevant clinical diseases, and explores potential therapeutic modalities. This review is intended to give researchers a better understanding of fatty infiltration and to contribute new ideas to the prevention and treatment of clinical musculoskeletal diseases.

Associations between Power Training-Induced Changes in Body Composition and Physical Function in Older Men: A Pre-Test-Post-Test Experimental Study

BACKGROUND

It is well-established that cross-sectional measurements of poor body composition are associated with impaired physical function and that power training effectively enhances total lean mass and physical function in older adults. However, it is unclear if power training-induced changes in body composition are associated with improved physical function in older adults.

AIM

The present study investigated associations between body composition and physical function cross-sectionally and with power training-induced changes in older men.

METHODS

Forty-nine older men (68 ± 5 yrs) completed a 10-week biweekly power training intervention. Body composition was measured using dual-energy X-ray absorptiometry. Physical function was assessed as a composite Z-score combining measures from Sit-to-stand power, Timed up-and-go time, and loaded and unloaded Stair-climbing time (15 steps). Linear and quadratic regression analyses were performed to assess associations between body composition and physical function.

RESULTS

At baseline, total (R2 = 0.11, p < 0.05) and percentage body fat (R2 = 0.15, p < 0.05) showed a non-linear relationship with physical function. The apex of the quadratic regression for body composition was 21.5% body fat. Furthermore, there was a non-linear relationship between changes in body fat percentage and physical function from pre- to post-intervention (R2 = 0.15, p < 0.05).

CONCLUSION

The present study's findings indicate that participants with a body composition of ~20% body fat displayed the highest level of physical function at baseline. Furthermore, despite small pre-post changes in body fat, the results indicate that those who either preserved their body fat percentage or experienced minor alterations observed the greatest improvements in physical function.

Comparing D3-Creatine Dilution and Dual-Energy X-ray Absorptiometry Muscle Mass Responses to Strength Training in Low-Functioning Older Adults

BACKGROUND

In contrast to dual-energy x-ray absorptiometry (DXA), the D3-creatine (D3Cr) dilution method provides a direct measure of skeletal muscle mass and in a cohort of older men has been strongly associated with health-related outcomes. However, sensitivity to detect changes in D3Cr-derived muscle mass due to an intervention is limited.

METHODS

Twenty-one older adults (≥70 years) with low-to-moderate physical function were randomized to a 15-week high-intensity strength training (ST) or a health education (HE) group. Full-body progressive intensity ST was performed 3 days per week.

RESULTS

The mean age was 82.1 years, with 64% females. After 15 weeks, both D3Cr muscle mass (MM; 2.29 kg; 95% CI: 0.22, 4.36) and DXA appendicular lean mass (ALM; 1.04 kg; 95% CI: 0.31, 1.77) were greater in ST group compared to HE. Baseline correlations between D3Cr MM and DXA ALM (r = 0.79; 95% CI: 0.53, 0.92) or total lean body mass (LBM; r = 0.79; 95% CI: 0.52, 0.91) were high. However, longitudinal changes in D3Cr MM were weakly correlated with changes in DXA ALM (r = 0.19; 95% CI: -0.35, 0.64) and LBM (r = 0.40; 95% CI: -0.13, 0.76). More participants showed positive response rates, defined as a >5% increase from baseline, with D3Cr MM (80%) than DXA measures (14%-43%).

CONCLUSIONS

A progressive ST intervention in low-functioning older adults increased D3Cr MM and DXA ALM. These data suggest that the D3Cr dilution is potentially sensitive to detect changes in muscle mass in response to resistance exercise training. These results are preliminary and could be used for planning larger trials to replicate these results.

Associations of physical function and body mass index with functional brain networks in community-dwelling older adults

Deficits in physical function that occur with aging contribute to declines in quality of life and increased mortality. There has been a growing interest in examining associations between physical function and neurobiology. Whereas high levels of white matter disease have been found in individuals with mobility impairments in structural brain studies, much less is known about the relationship between physical function and functional brain networks. Even less is known about the association between modifiable risk factors such as body mass index (BMI) and functional brain networks. The current study examined baseline functional brain networks in 192 individuals from the Brain Networks and mobility (B-NET) study, an ongoing longitudinal, observational study in community-dwelling adults aged 70 and older. Physical function and BMI were found to be associated with sensorimotor and dorsal attention network connectivity. There was a synergistic interaction such that high physical function and low BMI were associated with the highest network integrity. White matter disease did not modify these relationships. Future work is needed to understand the causal direction of these relationships.

Sex-specific associations between cardiovascular risk factors and physical function: the Gambian Bone and Muscle Ageing Study

BACKGROUND

In Sub-Saharan Africa, the prevalence of obesity, cardiovascular disease (CVD) and impaired physical function are increasing due to rapid urbanization. We investigated sex differences in associations between cardiac workload, arterial stiffness, peripheral vascular calcification (PVC) and physical function in Gambian adults.

METHODS

A total of 488 Gambians aged 40-75+ years were recruited (men: 239; and women: 249). Supine blood pressure and heart rate were measured to calculate rate pressure product and pulse pressure. Presence of PVC was determined from tibia peripheral quantitative computed tomography scans. Physical function was assessed by chair rise test (CRT), single two-legged jump (s2LJ) and hand grip strength (HGS). Body composition was measured by dual-energy x-ray absorptiometry; body size corrections were used to calculate fat mass index (FMI) and appendicular lean mass index (ALMI). Estimated glomerular filtration rate (eGFR) was measured from fasting blood samples. The relationship between rate pressure product, pulse pressure or presence of PVC (independent variable) with physical function parameters (dependent variable) was tested using linear regression. Sex-interactions were tested (p-int) adjusting for age, eGFR and ALMI/FMI. Results were expressed as mean differences between men and women with 95% confidence intervals. Mediation analyses used ALMI/FMI as mediator.

RESULTS

Women weighed less (54.7 kg ± 10.3 vs. 59.9 kg ± 10.3) and were shorter (157.8 cm ± 6.0 vs. 169.2 cm ± 7.0) compared with men (both P < 0.0001). Women had higher FMI (6.8 kg/m2  ± 2.9 vs. 2.9 kg/m2  ± 2.0, P < 0.0001) and eGFR (263.7 mL/min/1.73 m2  ± 133.1 vs. 237.6 mL/min/1.73 m2  ± 134.6), but lower ALMI (6.2 kg/m2  ± 0.7 vs. 8.02 kg/m2  ± 1.0, P < 0.0001) compared with men. There were significant mean differences between men and women in rate pressure product and s2LJ power (-1.08 [-1.21, -0.95]) and force (-0.57 [-0.63, -0.51]), only after adjusting for age, eGFR and FMI. There were significant mean differences in the associations between pulse pressure and CRT power (-0.28 [-0.31, -0.25]), s2LJ power (-1.07 [-1.20, -0.93]) and HGS (-11.94 [-13.35, -10.54]); these differences were greater after adjusting for age, eGFR and FMI, than ALMI. There were similar differences in the associations between PVC and physical function parameters. In men, FMI mediated the association between rate pressuree product and CRT power (P = 0.002), s2LJ force (P < 0.001) and s2LJ power (P = 0.001). ALMI did not mediate associations for either men or women.

CONCLUSIONS

Multiple risk factors for CVD were associated with poorer physical function in men and were mediated by FMI. There is a need to identify strategies to slow/prevent the rising CVD burden and poor physical function in Sub-Saharan Africa.

Prevalence of sarcopenia in women at stable weight phase after Roux-en-Y gastric bypass

Objective

Evaluating the prevalence of sarcopenia in women submitted to bariatric surgery - Roux-en-Y gastric bypass. Design: Observational, cross-sectional study.

Subjects and methods

Women (18-65 years old) who underwent bariatric surgery (BG) ≥ 2 years and reached stable weight ≥ 6 months, were investigated. Control group (CG) comprised non-operated matched women with obesity. Body composition was determined through dual-energy X-ray absorptiometry. Low lean mass (LLM) was defined as appendicular lean mass index (ALM kg/height m2) < 5.5 kg/m2. Physical strength was assessed through dynamometer and sit-to-stand test (SST), whereas performance was assessed through 4-m gait speed and Short Physical Performance Battery Tests (SPPB). Sarcopenia was diagnosed in the presence of LLM and low strength.

Results

One-hundred and twenty women (60 in each group, 50 ± 9.7 years old) were investigated. All anthropometric and body composition parameters were lower in BG than in CG, whereas strength and performance were similar between groups. Women with reduced strength presented high total fat mass and low physical activity level (p < 0.005). LLM was observed in 35% of BG and in 18.3% of CG (p = 0.04), whereas sarcopenia was diagnosed in 28.3% of BG and in 16.6% of CG (p = 0.12). Sarcopenic women in BG had better performance both in SST (p = 0.001) and SPPB (p = 0.004). Total lean mass (OR:1.41, 95% CI [1.18; 1.69], p < 0.001) and obesity (OR: 38.2 [2.27; 644.12], p < 0.001) were associated with sarcopenia in the multivariate analysis.

Conclusion

Despite great weight loss, sarcopenia prevalence did not increase in BG and its presence was influenced by total lean mass and obesity.

Utility of multidetector computed tomography quantitative measurements in identifying sarcopenia: a propensity score matched study

OBJECTIVE

To evaluate the utility of multidetector computed tomography MDCT quantitative measurements in identifying sarcopenia.

MATERIALS AND METHODS

The clinical data and MDCT images of 64 patients of sarcopenia and 184 non-sarcopenic participants between October 2020 and January 2021were retrospectively analyzed. Propensity score matching was used to match the sarcopenic patients with the non-sarcopenic participants. Two radiologists independently measured the cross-sectional area (CSA) of skeletal muscle and intramuscular fat tissue and CT density of skeletal muscle at the middle L3 vertebral level on CT images of all participants. Intra-observer agreement was evaluated via intraclass correlation coefficients (ICC). A receiver operating characteristic (ROC) curve was built for each variable. Correlations between CT parameters and clinical data were assessed via Pearson or Spearman correlation coefficient.

RESULTS

A total of 74 participants (mean age 72 ± 4 years, range 66-85 years; 38 men and 36 women) were included, comprising 37 sarcopenic patients and 37 non-sarcopenic participants. There were no significant intergroup differences regarding age, sex ratio, and body mass index (BMI) (P < 0.05). The CSA and density of skeletal muscle measured by two radiologists were reliable (ICC ≥ 0.75, P < 0.001). Compared with the sarcopenic group, the non-sarcopenic group had a significantly greater CSA and CT density of the total skeletal muscle (TSM) and paraspinal skeletal muscle (PSM) and skeletal muscle index at L3 level (L3 SMI) (P < 0.05). The fat infiltration ratio (FIR) of TSM, PSM, and psoas muscle was significantly higher in the sarcopenic group than that in non-sarcopenic participants (P < 0.05). ROC curve analysis showed the PSM FIR + PSM CT density (PSM D) had the best predictive value for sarcopenia (AUC = 0.836). The PSM FIR and age were moderately positively correlated (r = 0.410, P < 0.001).

CONCLUSION

Fat infiltration of skeletal muscle had better predictive value than L3 SMI in the diagnosis of sarcopenic. The PSM FIR + PSMD had the best predictive value for sarcopenia, which was moderately positively correlated with age.

Associations of health behaviors, food preferences, and obesity patterns with the incidence of mild cognitive impairment in the middle-aged and elderly population: An 18-year cohort study

BACKGROUND

There were few studies to examine the associations of food preferences and obesity patterns with the incident mild cognitive impairment (MCI). Therefore, this study aimed to examine the associations of health behaviors, food preferences, and with the incidence of MCI.

METHODS

All participants aged ≥ 55 years were potential eligible. The types of health behaviors and food preferences were recorded using the valid questionnaire. The obesity patterns were defined as follows:G-/A-, G+/A- or G-/A+, and G+/A+. The cognition tests included immediate and delayed recall, counting backward from 20, and serial 7 subtraction. The total cognitive score ranged from 0 to 27. Subjects with a score < 7 were considered as MCI.

RESULTS

There were 8236 subjects included in this study. Martial arts, ping pong, and reading or writing were associated with the lower incident MCI (P = 0.039, 0.006, and 0.016, respectively). However, TV or computer usage was associated with the higher incident MCI (P = 0.029; HR: 1.455; and HR 95% CI: 1.040- 2.036). Fast foods, soft/sugared drinks, and salty snack foods increased the incident MCI (P< 0.001, = 0.032, and 0.002, respectively). G+/A- or G-/A+ and G+/A+ were associated with the lower incident MCI (P = 0.018 and < 0.001, respectively).

LIMITATIONS

The basic mechanisms of health behaviors, food preferences, and obesity patterns on the risk of MCI were not fully explained.

CONCLUSION

Reading or writing and G+/A+ were associated with the lower incident MCI. However, TV or computer usage and fast foods were associated with the higher incident MCI.

Objectively assessed physical activity patterns and physical function in community-dwelling older adults: a cross-sectional study in Taiwan

OBJECTIVES

To objectively assess light physical activity (PA), moderate-to-vigorous PA (MVPA), step counts and number of 10 min MVPA bouts and their association with physical function among older adults.

DESIGN

Cross-sectional design.

SETTING

Urban community setting in Taiwan.

PARTICIPANTS

127 Taiwanese older adults aged over 65 years (mean age=70.8±5.3 years; 72% women).

PRIMARY AND SECONDARY OUTCOME MEASURES

Triaxial accelerometers were used to measure PA variables for 10 hours/day for seven consecutive days. Then, five physical function components (handgrip strength, single-leg stance, 5-metre walk speed, timed up and go and sit-to-stand test) were measured. Multiple linear regressions were used to perform separate analyses for older men and women.

RESULTS

For older women, daily MVPA time (β: 0.39, 95% CI: 0.12, 0.64; p=0.004), daily step counts (β: 0.46, 95% CI: 0.12, 0.78; p=0.009) and number of 10 min MVPA bouts (β: 0.27, 95% CI: 0.001, 0.53; p=0.049) were positively associated with handgrip strength after adjusting for accelerometer wear time, sedentary time and other confounders. Furthermore, daily MVPA time was positively associated with a single-leg stance (β: 0.25, 95% CI: 0.02, 0.49; p=0.036) and higher daily step counts were associated with shorter walking speed performance (β: -0.31, 95% CI: -0.57, -0.001; p=0.049). None of the variables of the objectively assessed PA patterns was associated with physical function outcomes among older men due to their small sample size.

CONCLUSIONS

Daily MVPA, MVPA bouts of at least 10 min and accumulated daily steps are important for improving physical function among older women. Future prospective research should establish causal associations between PA patterns and functional ability among older adults.

Trunk fat mass correlates with balance and physical performance in a community-dwelling elderly population: Results from the Korean Frailty and aging cohort study

This study aimed to investigate whether trunk fat mass measured using dual-energy X-ray absorptiometry (DEXA) correlates with balance and physical performance.This study utilized 2-year baseline data pertaining to 3014 participants from the database of the Korean frailty and aging cohort study. The trunk lean mass and fat mass were measured by DEXA. Trunk fat mass index (tFMI) was established using the following standard equation: Trunk fat mass (Kg)/height (m). The clinical balance tests were performed using the timed up and go test (TUG), total balance score in short physical performance battery (SPPB). We performed SPPB and evaluated independence of daily living using activities of daily living, instrumental activities of daily living (IADL), sarcopenia screening tool (SARC-F) and both hand grip power. In our study, we tried to check the correlation of tFMI with balance and physical performance and to determine the factors associated with tFMI.The tFMI was positively correlated with mean values of 4 m gait speed, repeat chair stand time in SPPB, TUG, and SARC-F and negatively correlated with hand grip, IADL, total balance test score in SPPB, total SPPB score, and age. The results of the multiple generalized linear model analysis that assessed the factors associated with balance and physical performance indicated that tFMI had a significant correlation with repeat chair stand time in SPPB (seconds) (Beta estimate [B]: 0.252), TUG (seconds) (B: 0.25), 4 m gait speed (seconds) (B: 0.055), and total balance score in SPPB (B: -0.035).Higher tFMI using DEXA was correlated with low physical performance and balance, indicating that trunk fat mass was associated with balance and physical performance in community-dwelling older people.

Consumption of a Specially-Formulated Mixture of Essential Amino Acids Promotes Gain in Whole-Body Protein to a Greater Extent than a Complete Meal Replacement in Older Women with Heart Failure

Heart failure in older individuals is normally associated with a high body mass index and relatively low lean body mass due to, in part, a resistance to the normal anabolic effect of dietary protein. In this study we have investigated the hypothesis that consumption of a specially-formulated composition of essential amino acids (HiEAAs) can overcome anabolic resistance in individuals with heart failure and stimulate the net gain of body protein to a greater extent than a commercially popular protein-based meal replacement beverage with greater caloric but lower essential amino acid (EAA) content (LoEAA). A randomized cross-over design was used. Protein kinetics were determined using primed continuous infusions of L-(²H₅)phenylalanine and L-(²H₂)tyrosine in the basal state and for four hours following consumption of either beverage. Both beverages induced positive net protein balance (i.e., anabolic response). However, the anabolic response was more than two times greater with the HiEAA than the LoEAA (p < 0.001), largely through a greater suppression of protein breakdown (p < 0.001). Net protein accretion (g) was also greater in the HiEAA when data were normalized for either amino acid or caloric content (p < 0.001). We conclude that a properly formulated EAA mixture can elicit a greater anabolic response in individuals with heart failure than a protein-based meal replacement. Since heart failure is often associated with obesity, the minimal caloric value of the HiEAA formulation is advantageous.

Aging and Imaging Assessment of Body Composition: From Fat to Facts

The aging process is characterized by the chronic inflammatory status called "inflammaging", which shares major molecular and cellular features with the metabolism-induced inflammation called "metaflammation." Metaflammation is mainly driven by overnutrition and nutrient excess, but other contributing factors are metabolic modifications related to the specific body composition (BC) changes occurring with age. The aging process is indeed characterized by an increase in body total fat mass and a concomitant decrease in lean mass and bone density, that are independent from general and physiological fluctuations in weight and body mass index (BMI). Body adiposity is also re-distributed with age, resulting in a general increase in trunk fat (mainly abdominal fat) and a reduction in appendicular fat (mainly subcutaneous fat). Moreover, the accumulation of fat infiltration in organs such as liver and muscles also increases in elderly, while subcutaneous fat mass tends to decrease. These specific variations in BC are considered risk factors for the major age-related diseases, such as cardiovascular diseases, type 2 diabetes, sarcopenia and osteoporosis, and can predispose to disabilities. Thus, the maintenance of a balance rate of fat, muscle and bone is crucial to preserve metabolic homeostasis and a health status, positively contributing to a successful aging. For this reason, a detailed assessment of BC in elderly is critical and could be an additional preventive personalized strategy for age-related diseases. Despite BMI and other clinical measures, such as waist circumference measurement, waist-hip ratio, underwater weighing and bioelectrical impedance, are widely used as a surrogate measure for body adiposity, they barely reflect the distribution of body fat. Because of the great advantages offered by imaging tools in research and clinics, the attention of clinicians is now moving to powerful imaging techniques such as computed tomography, magnetic resonance imaging, dual-energy X-ray absorptiometry and ultrasound to obtain a more accurate estimation of BC. The aim of this review is to present the state of the art of the imaging techniques that are currently available to measure BC and that can be applied to the study of BC changes in the elderly, outlining advantages and disadvantages of each technique.

Association between abductor muscle strength and functional outcomes in hip-fractured patients: a cross-sectional study

OBJECTIVES

To explore associations between abductor strength and functionality in hip-fracture patients.

METHODS

Ninety-six participants (70-84 years) followed a 12-week physiotherapy programme emphasizing hip abductor strengthening. The abductor's isometric strength, the hip strength asymmetry (HSA), expressing the ratio of abductor strength in the fractured versus the contralateral hip, and the patients' functional level were recorded 3 months post-intervention. Functionality was assessed using the Timed Up & Go (TUG) test and the Lower Extremity Functional Scale (LEFS-Greek).

RESULTS

Abductor isometric strength and HSA were correlated negatively with TUG test (Pearson's r: -0.881 and -0.810, respectively; p⟨0.001) and positively with LEFS-Greek (Spearman's ρ: 0.668 and 0.404, respectively; p⟨0.001). Of all independent variables examined, abductor isometric strength was the main predictor of functional capacity, being strongly and directly associated with a faster TUG test time (p⟨0.001) and a better LEFS-Greek score (p⟨0.001). Abductor's isometric strength and age explained 79.0% and 49.5%, whereas HSA and age explained 69.7% and 41.9% of TUG and LEFS-Greek variance, respectively.

CONCLUSIONS

Abductor isometric strength was the main predictor of hip-fracture patients' functionality, strongly enhancing the measured functional outcomes. Hip abductor strengthening appears to be of major clinical importance and may contribute significantly to the functional rehabilitation of hip-fractured patients.

Associations of total amount and patterns of objectively measured sedentary behavior with performance-based physical function

Although greater sedentary time has been found to be associated with negative health impacts, little is known whether the specific pattern of sedentary behavior (i.e. sedentary bouts, breaks and durations) are associated with physical function among older adults. The present study examined the associations between objectively measured sedentary behavior and physical function among older Japanese adults. A total of 174 male and 107 female community-dwelling older Japanese adults aged 65–84 years (mean age: 74.5 ± 5.2 years) were recruited. Sedentary behavior and physical activity were assessed using a triaxial accelerometer. Physical function was measured through hand grip strength, eye-open one leg standing, 5-m walking, and timed up and go tests. Forced-entry multiple linear regression models adjusted for potential confounders were performed. After adjustment, total daily sedentary time and duration of prolonged sedentary bouts (both ≥ 30 min) were positively associated with time spent on the 5-m walking stage and timed up and go tests in older women; however, no significant associations were observed in older men or the whole sample. This paper highlights the importance of developing sedentary behavior change strategies for interventions aiming to improve mobility in in older women. Further evidence from a prospective study is required to establish directions of causality between sedentary behavior and mobility.

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This study used triaxial accelerometers and standardized physical fitness tests.

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Total daily sedentary time was negatively associated with mobility in older women.

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Duration of prolonged sedentary bouts was negatively related to mobility in older women.

Reduced body weight or increased muscle quality: Which is more important for improving physical function following exercise and weight loss in overweight and obese older women?

The purpose of this study was to examine the relative contributions of changes in muscle quality and body composition to changes in lower-extremity physical function (LEPF) following a 6-month exercise and weight loss intervention in overweight and obese older women. Thirty-eight overweight and obese (BMI = 30.0 ± 4.4 kg/m²) older (age = 69.3 ± 4.1 y) women completed 6 months of multicomponent exercise (cardiorespiratory, resistance, balance and flexibility training) and weight loss (hypocaloric diet that reduced energy intake by ~500 kcal/d). Body composition was measured via dual-energy X-ray absorptiometry and muscle quality (N-m/kg) was defined as maximal concentric isokinetic knee torque divided by upper-leg lean mass. The standardized scores of four objective measures of physical function were summed to yield a composite LEPF Z-score. At 6 months, there were significant reductions in body weight (-9.6 ± 3.5%, p < 0.01), absolute fat mass (-6.8 ± 2.4 kg, p < 0.01) and relative adiposity (-4.9 ± 2.1%, p < 0.01). There were also improvements in both muscle quality (+1.6 ± 1.8 N-m/kg, p < 0.01) and individual measures of LEPF (11-57%, p < 0.01). Multivariate linear regression indicated that increased muscle quality was the strongest independent predictor of an improvement in LEPF Z-score (standardized β = 0.64, p < 0.01) and explained 34% of the variance. A reduction in body weight also predicted an improvement in LEPF, independent of the change in muscle quality. In conclusion, muscle quality can be increased in the presence of clinically meaningful weight loss, and is the primary determinant of improved physical function in overweight/obese older women.

Weight Loss Strategies in the Elderly: A Clinical Conundrum

The age-related concomitant loss of skeletal muscle and accumulation of excess adipose tissue have been commonly referred to as sarcopenic obesity. While weight loss may help mitigate the metabolic abnormalities linked to obesity, low fitness levels and muscle atrophy complicate the effectiveness of lifestyle interventions. Because of low levels of compliance, suboptimal economic efficiency, and low functional capacity, there has been no consensus on optimal therapy. This includes the use of high-protein diets that do not ensure muscle preservation during weight loss in this segment of the population. The primary objectives of this review are to discuss the relevance of sarcopenic obesity, examine the feasibility of weight loss in the elderly, and highlight new approaches to the problem.

Exploring the "Obesity Paradox" as a Correlate of Cognitive and Physical Function in Community-dwelling Black and White Older Adults

Objective

The obesity paradox has been documented in aged populations, yet it remains unclear if this paradox persists for physical and cognitive outcomes in community-dwelling older adult populations. Our study examines associations between body mass index (BMI) classification, cognitive function, and physical function. We also investigate whether these associations are modified by race or age.

Design

Cross-sectional study.

Setting

Senior residential sites and community centers in Saint Louis, Missouri.

Participants

Study participants included 331 adults, aged >55 years. Age was stratified into young-old (aged 55-74 years) and older (aged ≥75 years).

Outcome Measures

Physical function was measured using the mini-Physical Performance Test (mini-PPT) and grip strength. Cognitive function was assessed with the Short Blessed Test (SBT) and the Trail Making Tests (TMT-A and TMT-B) performance.

Results

Older adults who were obese had significantly better cognitive flexibility (TMT-B) performance than normal weight older adults (P=.02), and this association was not influenced by age or race. Adiposity was not associated with psychomotor speed (TMT-A), general cognition (SBT), or measures of physical function (Ps>.05).

Conclusion

In a diverse sample of community-dwelling older adults, we found partial support for the controversial obesity paradox. Our results suggest excess adiposity may be protective for executive function processes. Future research is needed to examine the underlying physiological processes linking adiposity to executive function in older adults.

Metabolic concerns in aging HIV-infected persons: from serum lipid phenotype to fatty liver

: Among HIV-infected persons, the assessment of nonalcoholic fatty liver disease (NAFLD) provides a window through which overall metabolic health can be evaluated. In this review, we summarize clinical data that support the roles of aging and metabolic dysregulation as factors contributing to fatty liver/NAFLD among HIV-infected persons.Age-related metabolic alterations include hepatic anatomic and functional changes, altered homeostasis of gastrointestinal microbiota and anthropometric changes (such as a shift of body fat depots from the subcutaneous to the visceral compartment) that are often associated with the development of insulin resistance and increased cardiovascular risk.Fatty changes in the liver occur not only with metabolic disruption but also with virus-induced injury. Chronic hepatitis C virus infection is commonly associated with fatty liver, and can be related to both hepatitis C virus genotype and host metabolic features. Similarly, HIV infection is associated with fatty liver as a result of multiple viral and host factors. Clearly, lipodystrophy, dysregulation of the gut-liver axis and HIV infection itself may each contribute simultaneously to NAFLD pathogenesis. Although lifestyle changes are the mainstay of treatment, to date no drug has specifically been approved for use in persons with NAFLD. Moreover, current guidelines provide no specific therapeutic recommendations for persons with NAFLD older than 65 years.Well-designed studies characterizing the epidemiology, pathogenesis, clinical outcomes and potential therapeutic interventions for liver disease and associated metabolic comorbidities in older HIV-infected patients are urgently needed.

Body Composition and Physical Function in Older Adults with Various Comorbidities

BACKGROUND

Lower muscle and higher fat mass are characteristics of older adults; their physical function is also characterized by slower gait speed and weaker strength. However, the association between specific body composition and physical function is unclear.

METHODS

We examined the association between body composition and physical performance using combined cross-sectional data of 1,821 participants from 13 clinical studies at Wake Forest University that used a consistent battery of tests. All participants were ≥60 years old and had one of the following conditions: healthy, osteoarthritis, coronary artery disease, obesity, heart failure, at elevated risk for disability, renal transplantation candidates, heart failure with preserved ejection fraction, moderate self-reported disability, hypertension, diabetes, or coronary artery disease, at high risk for cardiovascular disease. Data at enrollment from each study using uniform tools including body mass index (BMI), dual energy x-ray absorptiometry, physical performance assessment using 4 m walk speed, five chair rise time, handgrip strength, short physical performance battery (17), and Pepper Assessment Tool for Disability were analyzed.

RESULTS

Increased BMI was associated with slower walk speed, lower short physical performance battery, and higher Pepper Assessment Tool for Disability score. Increased percentage of body fat was associated with slower walk speed, lower hand grip strength, lower short physical performance battery scores, and higher Pepper Assessment Tool for Disability scores. Percent appendicular lean mass was associated with faster walk speed, higher handgrip strength, higher short physical performance battery, and lower Pepper Assessment Tool for Disability score. There were no significant discrepancies in relationship between body composition and physical function by gender except gender and BMI on chair-rise time.

CONCLUSIONS

Higher BMI and percent body fat were associated with poor physical function while percent appendicular lean mass was associated with better physical function. There was no significant discrepancy in the by gender.

Moderate-intensity physical activity is independently associated with lower-extremity muscle power in older women

Skeletal muscle power is a salient determinant of physical function in older adults, but its relationship with habitual physical activity has not been well-characterized. The aim of this study was to examine the association between moderate-intensity physical activity and lower-extremity muscle power in community-dwelling older women. Older women (n = 96, mean age = 73.9 ± 5.6 years, mean body mass index = 26.5 ± 4.7 kg/m(2)) underwent assessments for body composition via dual-energy X-ray absorptiometry and lower-extremity muscle power (watts) using the Nottingham power rig. The Community Health Activities Model Program for Seniors questionnaire was used to estimate weekly caloric expenditure in moderate-intensity physical activity (kcals/wk). Linear regression indicated that moderate-intensity physical activity was independently related to muscle power (standardized β = 0.20, p = .03), and this relationship remained following adjustment for covariates. Analysis of covariance revealed that women in the highest tertile of volume of physical activity had significantly greater muscle power than those with the lowest volume (199.0 vs. 170.7 watts, p < .05). Moderate-intensity physical activity was independently associated with lower-extremity muscle power in older women. Future intervention trials should determine if increasing habitual physical activity is associated with improvements in lower-extremity muscle power in older women.

Patient Characteristics and Comorbidities Influence Walking Distances in Symptomatic Peripheral Arterial Disease: A Large One-Year Physiotherapy Cohort Study

Objectives

The aim of this study is to investigate the association between age, gender, body-mass index, smoking behavior, orthopedic comorbidity, neurologic comorbidity, cardiac comorbidity, vascular comorbidity, pulmonic comorbidity, internal comorbidity and Initial Claudication Distance during and after Supervised Exercise Therapy at 1, 3, 6 and 12 months in a large sample of patients with Intermittent Claudication.

Methods

Data was prospectively collected in standard physiotherapy care. Patients received Supervised Exercise Therapy according to the guideline Intermittent Claudication of the Royal Dutch Society for Physiotherapy. Three-level mixed linear regression analysis was carried out to analyze the association between patient characteristics, comorbidities and Initial Claudication Distance at 1, 3, 6 and 12 months.

Results

Data from 2995 patients was analyzed. Results showed that being female, advanced age and a high body-mass index were associated with lower Initial Claudication Distance at all-time points (p = 0.000). Besides, a negative association between cardiac comorbidity and Initial Claudication Distance was revealed (p = 0.011). The interaction time by age, time by body-mass index and time by vascular comorbidity were significantly associated with Initial Claudication Distance (p≤ 0.05). Per year increase in age (range: 33–93 years), the reduction in Initial Claudication Distance was 8m after 12 months of Supervised Exercise Therapy. One unit increase in body-mass index (range: 16–44 kg/m²) led to 10m less improvement in Initial Claudication Distance after 12 months and for vascular comorbidity the reduction in improvement was 85m after 12 months.

Conclusions

This study reveals that females, patients at advanced age, patients with a high body-mass index and cardiac comorbidity are more likely to show less improvement in Initial Claudication Distances (ICD) after 1, 3, 6 and 12 months of Supervised Exercise Therapy. Further research should elucidate treatment adaptations that optimize treatment outcomes for these subgroups.

Sex-specific relationships of physical activity, body composition, and muscle quality with lower-extremity physical function in older men and women

OBJECTIVE

This study aims to determine the sex-specific relationships of physical activity, body composition, and muscle quality with lower-extremity physical function in older men and women.

METHODS

Seventy-nine community-dwelling men (n = 39; mean [SD] age, 76.1 [6.2] y; mean [SD] body mass index, 27.3 [3.8] kg/m(2)) and women (n = 40; mean [SD] age, 75.8 [5.5] y; mean [SD] body mass index, 27.0 [3.8] kg/m(2)) were assessed for physical activity via questionnaire, body composition via dual-energy x-ray absorptiometry scanning, leg extension power using the Nottingham power rig, and muscle quality (W/kg; the ratio of leg extension power [W] to lower-body mineral-free lean mass [kg]). A composite measure of physical function was obtained by summing Z scores from the 6-minute walk, 8-ft up-and-go test, and 30-second chair-stand test.

RESULTS

As expected, men had significantly greater levels of physical activity, lower adiposity, greater lean mass, higher leg extension power, and greater muscle quality compared with women (all P < 0.05). In linear regression analyses, muscle quality and physical activity were the strongest predictors of lower-extremity physical function in men and independently explained 42% and 29% of the variance, respectively. In women, muscle quality (16%) and percent body fat (12%) were independent predictors after adjustment for covariates.

CONCLUSIONS

Muscle quality is the strongest predictor of lower-extremity physical function in men and women, but sex impacts the importance of physical activity and adiposity. These findings suggest that older men and women may benefit from different intervention strategies for preventing physical disability and also highlight the importance of weight management for older women to preserve physical function.

Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat

BACKGROUND

Tesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT) in human immunodeficiency virus (HIV)-infected patients with lipodystrophy.

OBJECTIVES

1) To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF) or the National Cholesterol Education Program (MetS-NCEP) and the Framingham Risk Score (FRS), as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2) To explore the characteristics of patients who reached a threshold of VAT <140 cm2, a level associated with lower risk of adverse health outcomes, after 6 months of treatment with tesamorelin.

METHODS

Data were analyzed from two Phase 3 studies in which HIV-infected patients with excess abdominal fat were randomized in a 2:1 ratio to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) subcutaneously daily for 6 months, using ANOVA and ANCOVA models.

RESULTS

Metabolic syndrome (MetS-IDF or MetS-NCEP) and FRS were significantly associated with VAT at baseline. Presence of metabolic syndrome ([MetS-NCEP), triglyceride levels >1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively). No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm2 for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI) and baseline VAT (95% confidence interval [CI] 2.03; 7.44).

CONCLUSIONS

Individuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm2 was 3.9 times greater for tesamorelin-treated patients than that of patients receiving placebo.

Obese very old women have low relative hangrip strength, poor physical function, and difficulties in daily living

OBJECTIVES

To investigate whether anthropometric and body composition variables and handgrip strength (HS) were associated with physical function and independent daily living in 88-year-old Swedish women.

PARTICIPANTS

A cross-sectional analysis of 83 community-dwelling women aged 88 years who were of normal weight (n=30), overweight (n=29), and obese (n=24) was performed.

MEASUREMENTS

Body weight (Wt), height, waist circumference (WC), and arm circumference were assessed using an electronic scale and a measuring tape. Tricep skinfold thickness was measured using a skinfold calliper. Fat mass (FM) and fat-free mass (FFM) were measured using bioelectrical impedance analysis, and HS was recorded with an electronic grip force instrument. Linear regression was used to determine the contributions of parameters as a single predictor or as a ratio of HS to physical function (Short Form-36, SF-36PF) and instrumental activities of daily living (IADL).

RESULTS

Obese women had greater absolute FM and FFM and lower HS corrected for FFM and HS-based ratios (i.e., HS/Wt, HS/body mass index [BMI]) than their normal weight and overweight counterparts. After adjusting for physical activity levels and the number of chronic diseases, HS-based ratios explained more variance in SF-36PF scoring (R2, 0.52-0.54) than single anthropometric and body composition variables (R2, 0.45-0.51). WC, HS, and HS-based ratios (HS/Wt and HS/FFM) were also associated with independence in IADL.

CONCLUSION

Obese very old women have a high WC but their HS is relatively low in relation to their Wt and FFM. These parameters are better than BMI for predicting physical function and independent daily living.

Sarcopenia and sarcopenic obesity in patients with muscular dystrophy

Aging sarcopenia and muscular dystrophy (MD) are two conditions characterized by lower skeletal muscle quantity, lower muscle strength, and lower physical performance. Aging is associated with a peculiar alteration in body composition called “sarcopenic obesity” characterized by a decrease in lean body mass and increase in fat mass. To evaluate the presence of sarcopenia and obesity in a cohort of adult patients with MD, we have used the measurement techniques considered golden standard for sarcopenia that is for muscle mass dual-energy X-ray absorptiometry (DXA), for muscle strength hand-held dynamometry (HHD), and for physical performance gait speed. The study involved 14 adult patients with different types of MD. We were able to demonstrate that all patients were sarcopenic obese. We showed, in fact, that all were sarcopenic based on appendicular lean, fat and bone free, mass index (ALMI). In addition, all resulted obese according to the percentage of body fat determined by DXA in contrast to their body mass index ranging from underweight to obese. Skeletal muscle mass determined by DXA was markedly reduced in all patients and correlated with residual muscle strength determined by HHD, and physical performances determined by gait speed and respiratory function. Finally, we showed that ALMI was the best linear explicator of muscle strength and physical function. Altogether, our study suggests the relevance of a proper evaluation of body composition in MD and we propose to use, both in research and practice, the measurement techniques that has already been demonstrated effective in aging sarcopenia.

Subcutaneous adipose tissue insulin resistance is associated with visceral adiposity in postmenopausal women

OBJECTIVE

Whole body and subcutaneous adipose tissue (SAT) insulin resistance association with regional fat mass (FM) was determined.

METHODS

Postmenopausal women (mean ± SD; age 56 ± 4 years, n = 25) who were overweight or obese (BMI 29.9 ± 5.1 kg/m(2) ) were studied. Whole body and regional FM were measured by dual-energy X-ray absorptiometry (DXA) and computed tomography (CT). Women were studied during basal and insulin-stimulated (3-stage euglycemic clamp) conditions. Whole-body lipolysis was assessed by [(2) H5 ]-glycerol rate of appearance and abdominal and femoral SAT lipolysis by interstitial glycerol (microdialysis).

RESULTS

Whole body insulin resistance in skeletal muscle (insulin-stimulated glucose disposal) and adipose tissue (insulin-suppressed lipolysis) were independently related to trunk FM (r = -0.336 and 0.484, respectively), but not leg FM (r = -0.142 and -0.148, respectively). Local antilipolytic insulin resistance in abdominal, but not femoral, SAT was positively related to trunk FM (r = 0.552) and visceral FM (r = 0.511) but not related to leg FM (r = -0.289). Whole body and abdominal, but not femoral, adipose tissue insulin sensitivity were strongly related to skeletal muscle insulin sensitivity (r = -0.727 and -0.674, respectively).

CONCLUSIONS

The association of SAT insulin sensitivity (lipolysis) with adiposity and skeletal muscle insulin sensitivity was specific to the abdominal region.

Impact of body mass index on the relationship between muscle quality and physical function in older women

OBJECTIVES

To investigate the impact of body mass index (BMI) (normal weight, overweight, obese) on the relationship between muscle quality (MQ) and physical function in community-dwelling older women.

DESIGN

Cross-sectional study.

SETTING

University research laboratory.

PARTICIPANTS

Community-dwelling older women (n = 94, 73.6 ± 5.4 y) stratified by BMI (normal weight: 20.0-24.9 kg/m2; overweight: 25.0-29.9 kg/m2; obese: ≥ 30.0 kg/m2).

MEASUREMENTS

Body mass index using height and weight, leg extension power via the Nottingham power rig, body composition using dual-energy X-ray absorptiometry, and physical function (6-minute walk, 8-foot up-and-go, 30-second chair stand). Muscle quality was defined as leg power (watts) normalized for lower-body mineral-free lean mass (kg).

RESULTS

Following adjustments for covariates, muscle quality was significantly higher in women of normal BMI compared to overweight (10.0 ± 0.4 vs. 8.7 ± 0.4 watts/kg, p = 0.03). Muscle quality was a significant predictor of performance on the 6-minute walk and 8-foot up-and-go in normal and overweight women (all p < 0.05) and performance on the 30-second chair stand in normal and obese women (both p < 0.05). Body mass index did not significantly impact the association between MQ and physical function (all p > 0.05).

CONCLUSIONS

Muscle quality varies by BMI, yet the relationship to physical function is not significantly different across BMI groups. The results imply that interventions that increase MQ in older women may improve physical function, regardless of BMI.

Simplified method of clinical phenotyping for older men and women using established field-based measures

The purpose of this investigation was to determine body composition classification using field-based testing measurements in healthy elderly men and women. The use of isoperformance curves is presented as a method for this determination. Baseline values from 107 healthy Caucasian men and women, over the age of 65years old, who participated in a separate longitudinal study, were used for this investigation. Field-based measurements of age, height, weight, body mass index (BMI), and handgrip strength were recorded on an individual basis. Relative skeletal muscle index (RSMI) and body fat percentage (FAT%) were determined by dual-energy X-ray absorptiometry (DXA) for each participant. Sarcopenia cut-off values for RSMI of 7.26kg·m(-2) for men and 5.45kg·m(-2) for women and elderly obesity cut-off values for FAT% of 27% for men and 38% for women were used. Individuals above the RSMI cut-off and below the FAT% cut-off were classified in the normal phenotype category, while individuals below the RSMI cut-off and above the FAT% cut-off were classified in the sarcopenic-obese phenotype category. Prediction equations for RSMI and FAT% from sex, BMI, and handgrip strength values were developed using multiple regression analysis. The prediction equations were validated using double cross-validation. The final regression equation developed to predict FAT% from sex, BMI, and handgrip strength resulted in a strong relationship (adjusted R(2)=0.741) to DXA values with a low standard error of the estimate (SEE=3.994%). The final regression equation developed to predict RSMI from the field-based testing measures also resulted in a strong relationship (adjusted R(2)=0.841) to DXA values with a low standard error of the estimate (SEE=0.544kg·m(-2)). Isoperformance curves were developed from the relationship between BMI and handgrip strength for men and women with the aforementioned clinical phenotype classification criteria. These visual representations were used to aid in the classification and evaluation of sarcopenia, obesity, and sarcopenic-obesity in elderly individuals. Future research should replicate the current findings with an increased sample size and the development of tailored interventions for each body composition category.

Functional impairment is associated with low bone and muscle mass among persons aging with HIV infection

BACKGROUND

Disability and frailty are associated with osteoporosis, obesity, and sarcopenia. HIV-infected persons have early functional impairment, but the association between body composition and functional impairment is unknown.

METHODS

HIV-1-infected participants on combination antiretroviral therapy with virologic suppression, aged 45-65 years, had standardized physical function measures. In a nested analysis, 30 low- and 48 high-functioning cases and controls were matched by age, gender, and time since HIV diagnosis. Bone mineral density, fat mass, and lean body mass were assessed by dual-energy x-ray absorptiometry. Odds ratios (ORs) with 95% confidence intervals were obtained from conditional logistic regression.

RESULTS

Mean age was 53 years, mean CD4(+) lymphocytes 598 cells per microliter, and 96% had plasma HIV-1 RNA <50 copies per milliliter. Low- and high-function subjects had similar CD4(+) lymphocyte count and duration and type of antiretroviral therapy. Lower T scores at the hip [OR: 3.8 (1.1 to 12.5)] and lumbar spine [OR: 2.3 (1.1 to 4.5)] and lower lean body mass [OR: 1.1 (1.0 to 1.2)] were associated with significantly greater odds of low function (P ≤ 0.03). Lower insulin-like growth hormone [IGF-1; OR: 5.0 (1.4 to 20.0)] and IGF-1 binding protein-3 [OR: 3.3 (1.7 to 9.9)] increased the odds of low functional status (P ≤ 0.02). Fat mass and lower 25-OH vitamin D did not increase the odds of low functional status (P > 0.05).

CONCLUSIONS

Functional impairment in HIV-1-infected persons on successful antiretroviral therapy is associated with low muscle mass, low bone mineral density, and low IGF-1 and IGF-1 binding protein-3. These characteristics may be a manifestation of early "somatopause" in middle-aged HIV-infected adults.

Sarcopenic indices in community-dwelling older adults

BACKGROUND

Sarcopenic (SP) indices are used to estimate loss of skeletal lean mass and function and to determine the prevalence of SP in older adults. It is believed that older women and men with lower skeletal lean mass will be weaker and have more functional limitations.

PURPOSE

(1) To classify community-dwelling older adults using 2 common SP indices: appendicular lean mass/height² (ALM/ht²) and skeletal muscle index (SMI), and (2) to determine each indices value as indicators of lower extremity strength and physical function.

METHODS

The sample consisted of 154 community-dwelling older adults (111 women and 43 men; mean age = 82.4, SD = 3.6 years; mean body mass index = 25.8, SD = 4.4 kg/m). Each underwent whole-body dual-energy x-ray absorptiometry to assess lean mass. The 9-item modified Physical Performance Test and self-selected walking speed were used to evaluate function. Lower extremity strength was measured bilaterally using isokinetic dynamometry.

RESULTS

The ALM/ht² index classified 75 participants (49%) as SP and 79 (51%) as nonsarcopenic (NSP). The SMI classified 129 participants (84%) as SP and 25 (16%) as NSP. There were no differences in functional measures between groups by gender using either index after classification. The ALM/ht index was more strongly correlated with peak torque of all lower extremity muscle groups (r = 0.276-0.487) compared with the SMI (r = 0.103-0.344). There was no relationship between SP index and physical function.

DISCUSSION

There were marked differences in how 2 SP indices classified community-dwelling older adults. Lower extremity strength was lower in older women classified as SP than NSP using the ALM/ht index, but LE strength was not different in older men. However, no lower extremity strength differences were observed between SP and NSP men or women using the SMI classification. None of the SP index uniformly identified community-dwelling older adults with functional or strength deficits.

CONCLUSIONS

Detection of strength deficits using SP indices alone may be gender-specific and may not reflect strength or functional decline in community-dwelling men aged 80 years or older. Given associations between lower extremity strength and physical function, strength measures remain a better predictor of physical performance than SP indices for community-dwelling older men and women.

[Anthropometric, functional and explosive strength characteristics of physically active women over 50 years old in the city of Bogotá, Colombia]

OBJECTIVE

To analyze the relationship between different test measuring explosive strength and functionality of active women participating in a leisure sport program in order to describe the caracteristics of health status and look for tools for diagnosing and monitoring degenerative process.

METHODS

This study was conducted on 102 women physically active and without risk factors. Anthropometric, functional independence and explosive strength tests were applied.

RESULTS

Mean age 60.08 ± 5.35 years; body mass index: 26.81 ± 3.91; percentage of fat: 52.45 ± 4.75; percentage of muscle mass: 37.24 ± 6.77; tests of functional independence: maximum speed (30 meters): 9.39 ± 1.92 s; speed-agility (30 meters): 12.93 ± 1.59 s, and dynamic balance (6 meters): 21.9 ± 8.01 s. Explosive Strength (Bosco test): Squat Jump: 12.23 ± 3.05 cm, Countermovement Jump: 13.18 ± 3.04 cm and Countermovement Jump Arm swing: 14.80 ± 4.01 cm.

CONCLUSION

The statistical relationships found between body composition, explosive strength and functionality tests, are important tools for diagnosing and monitoring, and could improve the intervention models on the elderly.

Sex differences in the association of thigh fat and metabolic risk in older adults

We have previously shown a favorable association of subcutaneous leg fat with markers of insulin resistance and dyslipidemia in postmenopausal women. It is not known whether there is a sex dimorphism in the association of lower-body adiposity with reduced metabolic risk. Thus, our primary aim was to determine whether the favorable association of thigh subcutaneous fat, independent of abdominal fat, is also observed in older men. Mid-thigh and abdominal fat areas were measured by computed tomography (CT) in 108 older men and postmenopausal women (mean ± s.d.; 69 ± 7 years). Additionally, trunk and leg fat mass (FM) were measured by dual-energy X-ray absorptiometry (DXA). Markers of insulin resistance and dyslipidemia were determined from oral glucose tolerance tests and lipid and lipoprotein measurements, respectively. Outcomes were fasted and postchallenge (area under the curve, AUC) insulin (INS(AUC)) and glucose (GLU(AUC)), product of the insulin and glucose AUC (INS(AUC) × GLU(AUC)), triglycerides (TG), and high-density lipoprotein (HDL)-cholesterol. Consistent with our previous findings in postmenopausal women, adjusting for DXA trunk FM revealed a favorable association of DXA leg FM with the metabolic risk outcomes in both older men and postmenopausal women. Likewise, adjusting for CT abdominal visceral fat generally revealed a favorable association of CT thigh fat with metabolic risk outcomes in women, but not men. The discordance between the DXA and CT results in men is unclear but may be due to sex differences in visceral fat accrual. The mechanisms underlying the protective effect of thigh fat on metabolic risk factors need to be elucidated.

Relationship of Physical Performance with Body Composition and Bone Mineral Density in Individuals over 60 Years of Age: A Systematic Review

The purpose of this review was to examine the relationship between physical performance and body composition measurements, including fat/muscle mass and bone mineral density (BMD) in individuals ≥60 years of age. Various measurements used to assess body composition, BMD, and physical performance (PP) were discussed as well. Medline/PubMed, CINAHL, and SCIE were used to identify articles. After limiting the search for age and kind of physical performance measures, 33 articles were evaluated. Higher fat mass was associated with poorer physical performance while higher muscle mass was a predictor of better physical performance, especially in the lower extremities. Additionally, evidence showed that higher muscle fat infiltration was a determinant of poorer physical performance. BMD was shown to be a good predictor of physical performance although the relationship was stronger in women than in men. Developing standardized methods for PP measurements could help in further investigation and conclusions of its relationship with body composition.

Obesity, sarcopenia and their functional consequences in old age

The prevalence of obesity is high in older persons and recent trends show a rapid increase in this prevalence. Results from observational and intervention studies (i.e. weight loss studies) show the strong negative impact of obesity on functional status in old age. There are different potential pathways through which obesity may lead to functional decline in older persons. Furthermore, the presence of overweight and obesity during the life course and trends in medical care are likely to influence the impact of obesity on disability. The concepts sarcopenia (age-related loss of muscle mass) and dynapenia (age-related loss of muscle strength) receive a lot of research attention as potential determinants of functional decline in old age. There is no consensus on the definitions of these concepts. Recent studies conducted in large cohort studies of mainly community-dwelling older persons show that poor muscle strength is strongly associated with functional decline compared to low muscle mass. In several studies, no association between muscle mass and functional status was observed. Current research on the combination of obesity with poor muscle strength (dynapenic-obesity) suggests a potential additive effect of both components on poor functional status in old age which seems independent of the level of physical activity.

Association Between Muscle Mass, Leg Strength, and Fat Mass With Physical Function in Older Adults: Influence of Age and Sex

Objective: The purposes of this study were to determine the relationship between muscle mass, muscle strength, muscle quality, and fat mass with a composite measure of physical function in older adults, and to determine whether these relations differed by age and sex. Method: Participants consisted of 1280 adults aged ≥ 55 yr from the NHANES study. Reduced rank regression was used to identify patterns of muscle mass, muscle strength, muscle quality, and fat mass related to physical function. Results: A single relevant pattern emerged that included leg strength and fat mass as predictors of the 7 physical function variables. The leg strength loading was significantly greater than the fat mass loading in men and women aged 55-64 and ≥75, and differed between sexes. Conclusion: Leg strength and fat mass best predict physical function in older adults and the relative importance varies according to age and sex.

Osteoporosis and gait and balance disturbances in older sarcopenic obese New Zealanders

Bone, muscle, and fat may affect gait and balance in older adults. Osteoporosis was prevalent in low muscle mass participants and related to gait and balance deficits. Low muscle combined with high fat mass had more functional deficits and poorer bone health, which has implications for falls risk and fractures.

INTRODUCTION

Decreasing bone density and muscle mass and increasing fat mass may act synergistically to affect gait and balance in older adults.

METHODS

One hundred eighty-three older adults (age 72.7 +/- 6 years, range 56-93; body mass index 28.2 +/- 4.9, range 16.6-46.0) were recruited from a New Zealand falls prevention intervention trial. Total and appendicular skeletal muscle mass (ASM), percent fat, and bone mineralization were assessed by dual energy X-ray absorptiometry and used to characterize normal lean (NL, n = 51), sarcopenic (SS, n = 18), sarcopenic obese (SO, n = 29), and obese (OO, n = 85) phenotypes. Functional performance was assessed using timed up and go, chair stand, single leg stand, and step test. Regression models were adjusted for age, sex, medications, and physical activity.

RESULTS

Femoral neck osteoporosis was present in 22% SS, 17% SO, 12% NL, and 7% OO. Femoral neck osteoporosis with low ASM predicted poor chair stand performance (beta -3.3, standard error 1.6, p = 0.04). SO scored lowest on the chair stand (p = 0.03) and step test (p = 0.03). Higher ASM predicted faster timed up and go performance (p = 0.001).

CONCLUSIONS

Osteoporosis was prevalent in low ASM groups (SS and SO) and related to gait and balance deficits, particularly in the SO. This has implications for falls risk, fractures, and interventions.

Regional muscle and whole-body composition factors related to mobility in older individuals: a review

PURPOSE

To describe previously reported locomotor muscle and whole-body composition factors related to mobility in older individuals.

METHODS

A narrative review of the literature, including a combination of search terms related to muscle and whole-body composition factors and to mobility in older individuals, was carried out. Statistical measures of association and risk were consolidated to summarize the common effects between studies.

RESULTS

Fifty-three studies were reviewed. Muscle and whole-body factors accounted for a substantial amount of the variability in walking speed, with coefficients of determination ranging from 0.30 to 0.47. Muscle power consistently accounted for a greater percentage of the variance in mobility than did strength. Risks associated with high fat mass presented a minimum odds ratio (OR) of 0.70 and a maximum OR of 4.07, while the minimum and maximum ORs associated with low lean mass were 0.87 and 2.30 respectively. Whole-body and regional fat deposits accounted for significant amounts of the variance in mobility.

CONCLUSION

Muscle power accounts for a greater amount of the variance in the level of mobility in older individuals than does muscle strength. Whole-body fat accounts for a greater amount of the variance in level of mobility than does whole-body lean tissue. Fat stored within muscle also appears to increase the risk of a mobility limitation in older individuals.

Sarcopenic/obesity and physical capacity in older men and women: data from the Nutrition as a Determinant of Successful Aging (NuAge)-the Quebec longitudinal Study

Sarcopenia and obesity have been independently associated with physical capacity impairments. However, few studies have investigated the impact of sarcopenic/obesity on physical capacity in older individuals using objective measures of physical capacity and body composition. This study included 904 older individuals aged between 68 and 82 years old. Body composition (fat mass (FM) and lean body mass (LBM) by dual-energy X-ray absorptiometry (DXA)), physical capacity (timed up and go, chair stands, walking speed at normal and fastest pace, and one leg stand), sum of reported chronic conditions and physical activity level were measured. A global physical capacity score was then calculated giving a maximal score of 20. Finally, four groups were created within genders based on sarcopenia and obesity ((i) nonsarcopenic/nonobese; (ii) sarcopenic/nonobese; (iii) nonsarcopenic/obese; (iv) sarcopenic/obese). The four groups were significantly different for the sit-to-stand test and the one leg stand test (P < 0.05) and only for the one leg stand test in women (P < 0.05). In both genders results for the global physical capacity score revealed that both obese groups (sarcopenic and nonsarcopenic) were similar (P = 0.14 in men and P = 0.19 in women) and had a lower global physical capacity score compared to nonsarcopenic/nonobese individuals (P < 0.05). In addition, sarcopenic women displayed a higher score than both obese nonsarcopenic and obese sarcopenic groups (P < 0.01). Sarcopenic/obese men and women do not display lower physical capacity compared to nonsarcopenic/obese individuals in this cohort of well-functioning older men and women. Obesity per se appears to contribute more to lower physical capacity than sarcopenia.

Sex impacts the relation between body composition and physical function in older adults

OBJECTIVE

To determine the sex-specific relationships between physical activity, aerobic fitness, adiposity (%Fat), mineral-free lean mass (MFLM), and balance and gait performance in older adults.

METHODS

Eighty-five female and 49 male sedentary, healthy, community-dwelling older adults (mean [SD] age, 69.6 [5.4] and 70.3 [4.7] years, respectively) were evaluated on habitual physical activity via questionnaire, aerobic fitness by a maximal oxygen consumption treadmill test, whole and regional body composition by dual-energy x-ray absorptiometry, and lower extremity physical function using gait tasks and computerized dynamic posturography.

RESULTS

As expected, men had less body fat, more lean mass, and higher aerobic fitness than did women and tended to perform better on all lower extremity physical function tasks (all P <or= 0.1). Physical activity was not related to gait; however, fitness was related to gait in both sexes (r > 0.50, all P < 0.05). Body fat was related to gait in women (r = -0.38, P < 0.05) but not in men. Neither fitness nor body composition was related to balance in men, whereas in women, leg MFLM was positively associated (r = 0.27, P < 0.05). Women, but not men, with a greater ratio of body weight to leg MFLM performed worse on gait tasks (P < 0.001). There was an interaction with sex for %Fat on gait (P = 0.05) and for leg MFLM on balance (P < 0.05).

CONCLUSIONS

In sedentary healthy older adults, the relation between body composition, aerobic fitness, and balance and gait differs between sexes such that women are more strongly affected by alterations in body composition. Lower %Fat and preservation of lower body lean mass have important implications for reducing the risk of physical disability, especially in older women.