Associations of muscle force, power, cross-sectional muscle area and bone geometry in older UK men

Bone status in men with heart failure: results from the Studies Investigating Co-morbidities Aggravating Heart Failure

AIM

To assess bone status expressed as hip bone mineral density (BMD) in men with heart failure (HF).

METHODS AND RESULTS

A total of 141 male patients with HF underwent dual energy X-ray absorptiometry to assess their BMD. We analysed markers of bone metabolism. Patients were classified as lower versus higher BMD according to the median hip BMD (median = 1.162 g/cm2 ). Survival was assessed over 8 years of follow-up. Patients with lower BMD were older (71 ± 10 vs. 66 ± 9 years, p = 0.004), more likely to be sarcopenic (37% vs. 7%, p < 0.001) and to have lower peak oxygen consumption (absolute peak VO2 1373 ± 480 vs. 1676 ± 447 ml/min, p < 0.001), had higher osteoprotegerin and osteocalcin levels (both p < 0.05) compared to patients with higher BMD. Among 47 patients with repeated BMD assessments, a significant reduction in BMD was noted over 30 months of follow-up. In multivariate logistic regression analysis, serum osteocalcin remained independently related with lower BMD (odds ratio [OR] 1.738, 95% confidence interval [CI] 1.136-2.660, p = 0.011). Hip BMD and serum osteoprotegerin were independent predictors of impaired survival on Cox proportional hazard analysis (hazard ratio [HR] 0.069, 95% CI 0.011-0.444, p = 0.005, and HR 0.638, 95% CI 0.472-0.864, p = 0.004, respectively).

CONCLUSIONS

Patients with HF lose BMD over time. Markers of bone turnover can help in identifying patients at risk with osteocalcin being an independent marker of lower hip BMD and osteoprotegerin an independent predictor of death. HF patients with increased osteocalcin and osteoprotegerin may benefit from BMD assessment as manifest osteoporosis seems to be too late for clinically meaningful intervention in HF.

Lower Leg Power and Grip Strength Are Associated With Increased Fall Injury Risk in Older Men: The Osteoporotic Fractures in Men Study

BACKGROUND

Past research has not investigated both lower-extremity power and upper-extremity strength in the same fall injury study, particularly nonfracture fall injuries.

METHODS

In the Osteoporotic Fractures in Men Study (baseline: N = 5 994; age 73.7 ± 5.9 years; 10.2% non-White), fall injuries (yes/no) were assessed prospectively with questionnaires approximately every 3 years over 9 years. Maximum leg power (Watts) from Nottingham single leg press and maximum grip strength (kg) from handheld dynamometry were assessed at baseline and standardized to kg body weight. Physical performance included gait speed (6-m usual; narrow walk) and chair stands speed.

RESULTS

Of men with ≥1/4 follow-ups (N = 5 178; age 73.4 ± 5.7 years), 40.4% (N = 2 090) had ≥1 fall injury. In fully adjusted repeated-measures logistic regressions, lower power/kg and grip strength/kg had higher fall injury risk (trend across quartiles: both p < .0001), with lower quartiles at significantly increased risk versus highest Q4 except for grip strength Q3 versus Q4. Fall injury risk was 19% higher per 1 standard deviation (SD) lower power/kg (95% confidence interval [CI]: 1.12-1.26) and 16% higher per SD lower grip strength/kg (95% CI: 1.10-1.23). In models including both leg power/kg and grip strength/kg, odds ratios (ORs) were similar and independent of each other and physical performance (leg power/kg OR per SD = 1.13, 95% CI: 1.06-1.20; grip strength/kg OR per SD = 1.11, 95% CI: 1.05-1.17).

CONCLUSIONS

Lower leg power/kg and grip strength/kg predicted future fall injury risk in older men independent of physical performance. Leg power potentially identifies fall injury risk better than grip strength at higher muscle function, though grip strength may be more suitable in clinical/practice settings.

Effect of electrical stimulation training and detraining on abdominal muscle function

BACKGROUND

Electrical muscle stimulation (EMS) has been applied in many rehabilitation settings for muscle strengthening, facilitation of muscle contraction, re-education of muscle action, and maintenance of muscle strength and size during prolonged immobilization.

OBJECTIVE

The purpose of this study was to investigate effect of 8 weeks of EMS training on abdominal muscle function and to determine whether the training effect could be maintained after 4 weeks of EMS detraining.

METHODS

Twenty-five subjects performed EMS training for 8 weeks. Before and after 8 weeks of EMS training, and after 4 weeks of EMS detraining, muscle size (cross-sectional area [CSA] of the rectus abdominals [RA] and lateral abdominal wall [LAW]), strength, endurance, and lumbopelvic control (LC) were measured.

RESULTS

There were significant increases in CSA [RA (p< 0.001); LAW (p< 0.001)], strength [trunk flexor (p= 0.005); side-bridge (p< 0.05)], endurance [trunk flexor (p= 0.010); side-bridge (p< 0.05)], and LC (p< 0.05) after 8 weeks of EMS training. The CSA of the RA (p< 0.05) and the LAW (p< 0.001) were measured after 4 weeks of detraining and they were greater than that of the baseline. There were no significant differences in abdominal strength, endurance, and LC between baseline measurements and post-detraining.

CONCLUSION

The study indicates that there is less of a detraining effect on muscle size than on muscle strength, endurance, and LC.

Bone Microarchitecture Decline and Risk of Fall and Fracture in Men With Poor Physical Performance-The STRAMBO Study

CONTEXT

High fracture risk in individuals with low muscle strength is attributed to high risk of falls.

OBJECTIVE

This work aims to study the association of muscle mass and physical performance with bone microarchitecture decline and risk of fall and nonvertebral fracture in men.

METHODS

A prospective, 8-year follow-up of a cohort was conducted among the general population. A total of 821 volunteer men aged 60 and older participated. Hip areal bone mineral density (aBMD) and appendicular lean mass (ALM) were assessed at baseline by dual x-ray absorptiometry. Lower-limb relative ALM (RALM-LL) is ALM-LL/(leg length)2. The physical performance score reflects the ability to perform chair stands and static and dynamic balance. Bone microarchitecture was assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and after 4 and 8 years. Statistical analyses were adjusted for shared risk factors. Outcome measurements included the rate of change in the HR-pQCT indices, incident falls, and fractures.

RESULTS

Cortical bone loss and estimated bone strength decline were faster in men with low vs normal RALM-LL (failure load: -0.74 ± 0.09 vs -0.43 ± 0.10%/year; P < .005). Differences were similar between men with poor and those with normal physical performance (failure load: -1.12 ± 0.09 vs -0.40 ± 0.05%/year; P < .001). Differences were similar between men having poor performance and low RALM-LL and men having normal RALM-LL and performance (failure load: -1.40 ± 0.17 vs -0.47 ± 0.03%/year; P < .001). Men with poor physical performance had a higher risk of fall (hazard ratio [HR] = 3.52; 95% CI, 1.57-7.90, P < .05) and fracture (HR = 2.68; 95% CI, 1.08-6.66, P < .05).

CONCLUSION

Rapid decline of bone microarchitecture and estimated strength in men with poor physical performance and low RALM-LL may contribute to higher fracture risk.

Exogenous parathyroid hormone attenuates ovariectomy-induced skeletal muscle weakness in vivo

Osteoporosis commonly affects the elderly and is associated with significant morbidity and mortality. Loss of bone mineral density induces muscle atrophy and increases fracture risk. However, muscle lipid content and droplet size are increased by aging and mobility impairments, inversely correlated with muscle function, and a cause of reduced motor function. Teriparatide, the synthetic form of human parathyroid hormone (PTH) 1-34, has been widely used to treat osteoporosis. Although PTH positively affects muscle differentiation in vitro, the precise function and mechanisms of muscle mass and power preservation are still poorly understood, especially in vivo. In this study, we investigated the effect of PTH on skeletal muscle atrophy and dysfunction using an ovariectomized murine model. Eight-week-old female C57BL/6J mice were ovariectomized or sham-operated. Within each surgical group, the mice were divided into PTH injection or control subgroups. Motor function was evaluated based on grip strength, treadmill running, and lactic acid concentration. PTH receptor was expressed in skeletal muscle cells and myoblasts. PTH inhibited ovariectomy-induced bone loss but not uterine atrophy or increased body weight; PTH not only abolished ovariectomy-induced reduction in grip strength and maximum running speed, but also significantly reduced the ovariectomy-induced increase in lactic acid concentration (compared with that observed in the vehicle control). PTH also abrogated the ovariectomy-induced reduction in the oxidative capacity of muscle fibers, their cross-sectional area, and intramyocellular lipid content, and induced cell proliferation, cell migration, and muscle differentiation, while reducing lipid secretion by C2C12 myoblasts via the Wnt/β-catenin pathway. PTH significantly ameliorated muscle weakness and attenuated exercise-induced lactate levels in ovariectomized mice. Our in vitro study demonstrated that PTH/Wnt signaling regulated the proliferation, migration, and differentiation of myoblasts and also reduced lipid secretion in myoblasts. Thus, PTH could regulate several aspects of muscle function and physiology, and may represent a novel therapeutic strategy for patients with osteoporosis.

Mechanography assessment of fall risk in older adults: the Vietnam Osteoporosis Study

BACKGROUND

Jumping mechanography is a technology for quantitatively assessing muscular function and balance in older adults. This study sought to define the association between jumping mechanography parameters and fall risk in Vietnamese individuals.

METHODS

The study involved 375 women and 244 men aged 50 years and older, who were recruited from the general population in Ho Chi Minh City (Vietnam). The individuals had been followed for 2 years. At baseline, Esslinger Fitness index (EFI), jumping power, force, velocity of lower limbs, and the ability to maintain balance were measured by a Leonardo Mechanograph Ground Reaction Force system (Novotec Medical, Pforxheim, Germany). The incidence of falls during the follow-up period was ascertained from self-report. Logistic regression analysis was used to analyse the association between jumping mechanography parameters and fall risk.

RESULTS

The average age of participants at baseline was 56.7 years (SD 5.85). During the 2 year follow-up, 92 falls were reported, making the incidence of fall at ~15% [95% confidence interval (CI), 12.1 to 18.2]. The incidence of fall increased with advancing age, and women had a higher incidence than men (17.6% vs. 10.7%; P = 0.024). In univariate analysis, maximal velocity [odds ratio (OR) 0.65; 95% CI, 0.52 to 0.82], maximal force (OR 0.83; 95% CI, 0.65 to 1.04), and maximal power (OR 0.68; 95% CI, 0.52 to 0.88) were each significantly associated with fall risk. EFI was not significantly associated with fall risk (OR 1.09; 95% CI, 0.86 to 1.39). However, in a multiple logistic regression model, greater maximum velocity was associated with lower odds of fall (OR 0.38; 95% CI, 0.16 to 0.92).

CONCLUSIONS

These data suggest that jumping mechanography is a useful tool for assessing fall risk in older adults of Vietnamese background.

Reproducibility and agreement between three positions for handgrip assessment

The protocol established for taking hand grip dynamometry measurements determines that the patient must be in a sitting position. This protocol cannot be applied due to the patient’s conditions in some cases, such as abdominal surgery, musculoskeletal spine or hip injuries. The purpose was to determine the reproducibility and level of agreement between the Handgrip dynamometry in supine position with the elbow flexed or extended, and the one measured in the sitting position, the design was a descriptive cross-sectional study. The population were young apparently healthy between 18 and 30 years of age (N = 201). Handgrip measurement was performed on both upper limbs in a sitting position with a flexed elbow, a supine position with a flexed elbow, and supine position with the elbow extended. Reproducibility was nearly perfect in all positions (ICC 0.95–0.97). Regarding the level of agreement for the comparison between sitting and supine positions with a flexed elbow, an average difference of − 0.406. For supine position with an extended elbow and supine position with a flexed elbow, the average difference was − 1.479. Considering the results, clinicians or researchers can choose any of the positions evaluated herein and obtain reliable results as long as the standardization process is followed.

The Role of Irisin in Exercise-Mediated Bone Health

Exercise training promotes physical and bone health, and is the first choice of non-drug strategies that help to improve the prognosis and complications of many chronic diseases. Irisin is a newly discovered peptide hormone that modulates energy metabolism and skeletal muscle mass. Here, we discuss the role of irisin in bone metabolism via exercise-induced mechanical forces regulation. In addition, the role of irisin in pathological bone loss and other chronic diseases is also reviewed. Notably, irisin appears to be a key determinant of bone mineral status and thus may serve as a novel biomarker for bone metabolism. Interestingly, the secretion of irisin appears to be mediated by different forms of exercise and pathological conditions such as diabetes, obesity, and inflammation. Understanding the mechanism by which irisin is regulated and how it regulates skeletal metabolism via osteoclast and osteoblast activities will be an important step toward applying new knowledge of irisin to the treatment and prevention of bone diseases such as osteolysis and other chronic disorders.

Factors associated with relative muscle strength in patients with type 2 diabetes mellitus

OBJECTIVES

Some patients with type 2 diabetes mellitus (T2DM) experience decreased mobility associated with lower relative muscle strength (normalized with muscle mass). This study aimed to identify factors predicting relative muscle strength of patients with T2DM assessed at regular clinical visits.

METHODS

A total of 144 T2DM patients underwent fasting blood drawing (determining white blood cell count [WBC], diabetic kidney disease [DKD], and glycated hemoglobin [HbA1c]) and the assessment of body composition, diabetic peripheral neuropathy (DPN), activity level, and muscle strength (grip, knee extensor, and ankle plantar flexor strength). One-way ANOVA and multiple regression models were used to identify factors associated with the relative muscle strength.

RESULTS

Our data showed that age, diabetes duration, fat percentage, WBC, DPN, and DKD were negatively associated with the relative muscle strength. Specifically, a greater WBC was associated with lower relative muscle strength of both distal and proximal muscle groups of extremities after the adjustment of other associated factors. DPN was associated with lower relative strength of the distal muscle groups of extremities.

CONCLUSIONS

WBC may be used as a marker of inflammation, and greater count, even within the normal range, is negatively associated with the relative muscle strength in patients with T2DM.

Age- and Sex-Specific Changes in Lower-Limb Muscle Power Throughout the Lifespan

BACKGROUND

Our main goal was to evaluate the pattern and time course of changes in relative muscle power and its constituting components throughout the life span.

METHODS

A total of 1,305 subjects (729 women and 576 men; aged 20-93 years) participating in the Copenhagen Sarcopenia Study took part. Body mass index (BMI), leg lean mass assessed by dual-energy X-ray absorptiometry (DXA), and leg extension muscle power (LEP) assessed by the Nottingham power rig were recorded. Relative muscle power (normalized to body mass) and specific muscle power (normalized to leg lean mass) were calculated. Segmented regression analyses were used to identify the onset and pattern of age-related changes in the recorded variables.

RESULTS

Relative muscle power began to decline above the age of 40 in both women and men, with women showing an attenuation of the decline above 75 years. Relative muscle power decreased with age due to (i) the loss of absolute LEP after the fourth decade of life and (ii) the increase in BMI up to the age of 75 years in women and 65 years in men. The decline in absolute LEP was caused by a decline in specific LEP up to the age of 75 in women and 65 in men, above which the loss in relative leg lean mass also contributed.

CONCLUSIONS

Relative power decreased (i) above 40 years by the loss in absolute power (specific power only) and the increase in body mass, and (ii) above ~70 years by the loss in absolute power (both specific power and leg lean mass).

Normative values of muscle strength across ages in a 'real world' population: results from the longevity check-up 7+ project

BACKGROUND

Low muscle strength is a powerful predictor of negative health-related events and a key component of sarcopenia. The lack of normative values for muscle strength across ages hampers the practical appraisal of this parameter. The aim of the present study was to produce normative values for upper and lower extremity muscle strength across a wide spectrum of ages, in a large sample of community-dwellers recruited in the Longevity check-up (Lookup) 7+ project.

METHODS

Lookup 7+ is an ongoing project that started in June 2015 and conducted in unconventional settings (i.e. exhibitions, malls, and health promotion campaigns) across Italy with the aim of fostering the adoption of healthy lifestyles in the general population. Candidate participants are eligible for enrolment if they are 18+ years and provide written informed consent. Upper and lower extremity muscle strength is assessed by handgrip strength and five-repetition chair-stand [5 × sit-to-stand (STS)] tests, respectively. Cross-sectional centile and normative values for handgrip strength and 5 × STS tests from age 18 to 80+ years were generated for the two genders. Smoothed normative curves for the two tests were constructed for men and women using the lambda-mu-sigma method.

RESULTS

From 1 June 2015 to 30 May 2019, 11 448 participants were enrolled. The mean age of participants was 55.6 years (standard deviation: 11.5 years; range: 18-98 years), and 6382 (56%) were women. Normative values for handgrip strength and the 5 × STS test, both absolute and normalized by body mass index, were obtained for men and women, stratified by age groups. Values of upper and lower extremity muscle strength across ages identified three periods in life: an increase to peak in young age and early adulthood (18-24 years), preservation through midlife (25-44 years), and a decline from midlife onwards (45+ years).

CONCLUSIONS

Our study established age-specific and gender-specific percentile reference values for handgrip strength and the 5 × STS test. The normative curves generated can be used to interpret the assessment of muscle strength in everyday practice for the early detection of individuals with or at risk of sarcopenia.

Jump power, leg press power, leg strength and grip strength differentially associated with physical performance: The Developmental Epidemiologic Cohort Study (DECOS)

BACKGROUND

Weight-bearing jump tests that measure lower-extremity muscle power may be more strongly related to physical performance measures vs. non-weight-bearing leg press power, leg press strength and grip strength. We investigated if multiple muscle function measures differentially related to standard physical performance measures.

MATERIALS/METHODS

In the Developmental Epidemiologic Cohort Study (DECOS; N = 68; age 78.5 ± 5.5 years; 57% women; 7% minorities), muscle function measures included power in Watts/kg (functional, weight-bearing: jump; mechanical: Nottingham power rig; Keiser pneumatic leg press) and strength in kg/kg body weight (Keiser pneumatic leg press; hand-held dynamometry). Physical performance outcomes included 6 m usual gait speed (m/s), usual-paced 400 m walk time (seconds), and 5-repeated chair stands speed (stands/s).

RESULTS

Women (N = 31; 79.8 ± 5.0 years) had lower muscle function and slower gait speed compared to men (N = 25; 78.7 ± 6.6 years), though similar 400 m walk time and chair stands speed. In partial Pearson correlations adjusted for age, sex, race and height, muscle function measures were moderately to strongly correlated with each other (all p < 0.05), though the individual correlations varied. In multiple regression analyses, each muscle function measure was statistically associated with all physical performance outcomes in models adjusted for age, sex, race, height, self-reported diabetes, self-reported peripheral vascular disease and self-reported pain in legs/feet (all p < 0.05). Jump power (β = 0.75) and grip strength (β = 0.71) had higher magnitudes of association with faster gait speed than lower-extremity power and strength measures (β range: 0.32 to 0.58). Jump power (β = 0.56) had a slightly lower magnitude of association with faster 400 m walk time vs. Keiser power_{70% 1-RM} (β = 0.61), and a higher magnitude of association vs. Nottingham power, Keiser strength and grip strength (β range: 0.41 to 0.47). Jump power (β = 0.38) had a lower magnitude of association with chair stands speed than any other power or strength measures (β range: 0.50 to 0.65).

CONCLUSIONS

Jump power/kg and grip strength/kg may be more strongly related to faster gait speed, a standard measure of physical function and vital sign related to disability and mortality in older adults, compared to leg press power/strength. However, jump power/kg had a similar magnitude of association with 400 m walk time as Keiser power_{70% 1-RM}/kg and a lower magnitude of association with faster chair stands speed than the other muscle function measures. Importantly, choice of muscle function measures should carefully reflect the study focus and methodologic considerations, including population.

Association between anorexia of ageing and sarcopenia among Japanese older adults

BACKGROUND

Malnutrition plays an essential role in the mechanism of pathogenesis for sarcopenia. In late life, both food consumption and energy intakes decline. One of key factors for reduced energy intakes is anorexia of ageing. The aim of this study is to examine the association between anorexia of ageing and sarcopenia among community-dwelling elderly Japanese individuals.

METHODS

This uses population-based, cross-sectional cohort study of elderly Japanese individuals. Anorexia of ageing was assessed via a simplified nutritional appetite questionnaire. Handgrip strength and walking speed were tested, and skeletal muscle mass was assessed using a bio-impedance analysis device. Subjects with sarcopenia were defined as those who met the criteria of the Asian Working Group for Sarcopenia. The association between anorexia of ageing and sarcopenia was then analysed via multiple regression analysis.

RESULTS

In total, 9,496 elderly Japanese individuals were evaluated (mean age 74.1 ± 5.4 years; male, 47.0%). The prevalence of anorexia of ageing was 9.8% (n = 927) in the present study. The prevalence of sarcopenia in men was 1.1%, 1.8%, 6.1%, 10.1%, and 21.2% and was 1.6%, 3.3%, 3.6%, 4.8%, and 7.4% in women aged 65-69, 70-74, 75-79, 80-84, and 85 years and older, respectively. The prevalence of anorexia also showed an age-dependent increase in both sexes (P < 0.001, respectively). The prevalence of anorexia in men was 8.3%, 6.3%, 9.8%, 13.6%, and 12.9% and was 7.9%, 9.4%, 10.5%, 17.6%, and 17.1% in women aged 65-69, 70-74, 75-79, 80-84, and 85 years and older, respectively. In multivariable logistic regression model adjusted for the covariates except for albumin, anorexia of ageing was independently associated with sarcopenia (OR: 1.45, 95% CI: 1.07 to 1.95; P = 0.015). This significant association remained even after adjusting for all covariates including nutritional status (OR: 1.42, 95% CI: 1.06 to 1.92, P = 0.020).

CONCLUSIONS

Anorexia of ageing is associated with sarcopenia among Japanese elderly individuals. Further studies are needed to determine whether a causal association exists between anorexia and sarcopenia.

Muscular Maximal Strength Indices and Bone Variables in a Group of Elderly Women

The aim of the present study was to explore the relations between muscular maximal strength indices and bone parameters (bone mineral density [BMD], hip geometry indices, and trabecular bone score [TBS]) in a group of elderly women. This study included 35 healthy elderly women whose ages range between 65 and 75 yr (68.1 ± 3.1 yr). BMD (in gram per square centimeter) was determined for each individual by dual-energy X-ray absorptiometry at the whole body, lumbar spine (L1-L4), total hip (TH), and femoral neck (FN). L1-L4 TBS and hip geometry indices were also evaluated by dual-energy X-ray absorptiometry. Maximal muscle strength of bench press (1-repetition maximum [RM] bench press), maximal muscle strength of leg press (1-RM leg press), and handgrip were measured using validated methods. 1-RM bench press was positively correlated to TH BMD (r = 0.40; p < 0.05), FN BMD (r = 0.41; p < 0.05), FN section modulus (r = 0.33; p < 0.05), and FN cross-sectional moment of inertia (r = 0.35; p < 0.05). 1-RM leg press was positively correlated to TH BMD (r = 0.50; p < 0.01), FN BMD (r = 0.35; p < 0.05), FN cross-sectional area (r = 0.38; p < 0.05), and TBS (r = 0.37; p < 0.05). Handgrip was correlated only to FN cross-sectional moment of inertia (r = 0.43; p < 0.01). This study suggests that 1-RM bench press and 1-RM leg press are positive determinants of BMD in elderly women.

Associations between novel jump test measures, grip strength, and physical performance: the Osteoporotic Fractures in Men (MrOS) Study

BACKGROUND/AIMS

Weight-bearing jump tests measure lower extremity muscle power, velocity, and force, and may be more strongly related to physical performance than grip strength. However, these relationships are not well described in older adults.

METHODS

Participants were 1242 older men (mean age 84 ± 4 years) in the Osteoporotic Fractures in Men (MrOS) Study. Jump peak power (Watts/kg body weight), force (Newton/kg body weight) at peak power, and velocity (m/s) at peak power were measured by jump tests on a force plate. Grip strength (kg/kg body weight) was assessed by hand-held dynamometry. Physical performance included 400 m walk time (s), 6 m usual gait speed (m/s), and 5-repeated chair stands speed (#/s).

RESULTS

In adjusted Pearson correlations, power/kg and velocity moderately correlated with all performance measures (range r = 0.41-0.51; all p < 0.001), while correlations for force/kg and grip strength/kg were weaker (range r = 0.20-0.33; all p < 0.001). Grip strength/kg moderately correlated with power/kg (r = 0.44; p < 0.001) but not velocity or force/kg. In adjusted linear regression with standardized βs, 1 SD lower power/kg was associated with worse: 400 m walk time (β = 0.47), gait speed (β = 0.42), and chair stands speed (β = 0.43) (all p < 0.05). Associations with velocity were similar (400 m walk time: β = 0.42; gait speed: β = 0.38; chair stands speed: β = 0.37; all p < 0.05). Force/kg and grip strength/kg were more weakly associated with performance (range β = 0.18-0.28; all p < 0.05).

CONCLUSIONS/DISCUSSION

Jump power and velocity had stronger associations with physical performance than jump force or grip strength. This suggests lower extremity power and velocity may be more strongly related to physical performance than lower extremity force or upper extremity strength in older men.

Bone in heart failure

There is an increasing interest in osteoporosis and reduced bone mineral density affecting not only post-menopausal women but also men, particularly with coexisting chronic diseases. Bone status in patients with stable chronic heart failure (HF) has been rarely studied so far. HF and osteoporosis are highly prevalent aging-related syndromes that exact a huge impact on society. Both disorders are common causes of loss of function and independence, and of prolonged hospitalizations, presenting a heavy burden on the health care system. The most devastating complication of osteoporosis is hip fracture, which is associated with high mortality risk and among those who survive, leads to a loss of function and independence often necessitating admission to long-term care. Current HF guidelines do not suggest screening methods or patient education in terms of osteoporosis or osteoporotic fracture. This review may serve as a solid base to discuss the need for bone health evaluation in HF patients.

Clinical impact of skeletal muscle area in patients with non-small cell lung cancer treated with anti-PD-1 inhibitors

PURPOSE

The aim of this study was to elucidate the clinical impact of skeletal muscle area (SMA) in patients with non-small cell lung cancer (NSCLC) treated with anti-programmed cell death-1 (PD-1) inhibitors.

METHODS

Univariate and multivariate analyses were performed on data of 103 patients with advanced or recurrent NSCLC treated with anti-PD-1 inhibitors. The SMA was measured at the level of the third lumbar vertebral (L3) on computed tomography images using OsiriX software (32-bit, version 5.8; OsiriX, Geneva, Switzerland). The L3 muscle index (cm²/m²) was defined as the SMA (cm²) at the L3 level divided by the height (m) squared.

RESULTS

L3 muscle index ^Low was an independent predictor of both progression-free (P = 0.0399) and overall survival (P = 0.0155). Moreover, the disease control rate was significantly lower in the L3 muscle index ^Low group (49.0% [25/51]) than in the L3 muscle index ^High group (73.1% [38/52]; P = 0.0117). However, there was no significant difference between the response rates of the L3 muscle index ^Low group (21.6% [11/51]) and L3 muscle index ^High group (32.7% [17/52]; P = 0.2031).

CONCLUSIONS

L3 muscle index ^Low is an independent predictor of worse outcomes in NSCLC patients treated with anti-PD-1 inhibitors.

Are jumping mechanography assessed muscle force and power, and traditional physical capability measures associated with falls in older adults? Results from the Hertfordshire Cohort Study

OBJECTIVES

To explore associations between measures of lower limb muscle force, velocity and power from jumping mechanography (JM) and simple physical capability (PC) testing, and falls in community dwelling older adults.

METHODS

Participants performed a two-leg countermovement jump on a ground reaction force platform. Jump force, power and velocity were calculated. PC tests were 6m timed-up-and-go (TUG)(sec), grip strength (kg), gait speed (m/s) and chair rise time (secs). Two-three years after JM and PC testing, self-reported falls in the previous year were recorded, and logistic regression analysis used to determine whether JM and PC measures were associated with falls.

RESULTS

Fall and PC data were available for 258 (169 JM) participants. Mean (SD) age at baseline was 75(2.5) years, 50% (n=129) were women and 27% (n=70) had fallen. As power and velocity increased, the odds of being a faller decreased [(odds ratio (OR)=0.91, 95% confidence interval (CI) 0.85,0.98] and (OR=0.20, 95% CI 0.05 0.72) respectively). Whilst grip strength and TUG were associated with falling; relationships were attenuated after adjustment.

CONCLUSIONS

Jumping mechanography-measured muscle power and velocity were associated with lower risk of falls. In this relatively healthy cohort of older adults JM appears to be more sensitive measure of muscle deficits and falls risk than standard PC measures.

Age-dependent effects of caloric restriction on mTOR and ubiquitin-proteasome pathways in skeletal muscles

In skeletal muscles, calorie restriction (CR) preserves muscle mass in middle-aged rats but not younger rats. The underlying mechanisms for this age-specific response are unknown. Skeletal muscle mass depends on several factors, with protein synthesis and degradation playing major roles. Therefore, the purpose of this study was to investigate whether CR affects younger and older animals differently on mTOR signaling and ubiquitin-proteasome pathway (UPP). Four-, 8-, and 16-month-old rats, with or without 40% CR for a duration of 14 weeks, were sacrificed after an overnight fasting. Total protein content and the phosphorylation level of AKT, mTOR, S6K, and 4EBP1 and protein content of key markers in the UPP (FOXO3a, atrogin, MuRF1, ubiquitinated proteins, proteasome subunits alpha 7 and beta 5) were determined. Unlike younger rats, CR decreased the content of phosphorylated mTOR, S6K, phosphorylated S6K, FOXO3a, and ubiquitinated proteins in middle-aged rats. In conclusion, CR-induced reduction of content/ phosphorylation levels of key proteins in mTOR signaling and the UPP occurred in the middle-aged rats but not younger rats. The age-dependent effects of CR on mTOR signaling and the UPP indirectly explained the age-related effects of CR on muscle mass of animals.

Longitudinal Changes in Muscle Mass and Strength, and Bone Mass in Older Adults: Gender-Specific Associations Between Muscle and Bone Losses

Background

The aims of this study were to investigate the longitudinal changes in muscle and bone with aging, and to clarify the muscle-bone relationships.

Methods

In a community-based prospective study, a total of 172 men and 165 women aged ≥ 65 years who had performed body composition analysis and bone mineral density (BMD) by dual-energy x-ray absorptiometry at baseline and 5-year follow-up evaluations were included.

Results

The rate of BMD loss in total hip was significantly associated with baseline legs lean mass and loss rate of leg strength, but not with the rate of muscle mass losses in men (r = .205 in leg lean mass, r = .170 in loss rate of leg muscle strength, p < .05 respectively). However, in women, it was significantly correlated with the rate of leg lean mass loss, but not with baseline values, and the rate of loss in leg muscle strength (r = .169 in the rate of loss in leg lean mass, r = .246 in the rate of loss in leg muscle strength, p < .05 respectively). In multivariate analyses, the rates of decrease in leg muscle strength showed independent positive associations with loss in total hip BMD in both men and women (β = 0.023 for men and β = 0.045 for women, both p < .05 respectively).

Conclusion

There was a gender difference in muscle and bone mass changes with aging, and muscle-bone interactions as well. However, a longitudinal change in muscle strength was the most significant independent factor associated with bone loss for both genders.

Application of current sarcopenia definitions in spinal cord injury

OBJECTIVE

Little is known about how appropriate the working definitions of sarcopenia are in subjects with spinal cord injury (SCI). This study aimed to evaluate the application of current sarcopenia definitions in SCI.

METHODS

We compared 31 complete SCI men with 33 able-bodied age matched subjects. All were examined by whole body DXA (Norland XR 36, USA) regarding muscle and fat mass and by peripheral quantitative computed tomography (pQCT XCT-3000, Germany) in 66% of tibia's length (muscle cross sectional area, (CSA) in mm²). Low muscle mass was defined by skeletal muscle index, (SMI= appendicular lean mass (aLM)/height² in Kg/m²) and by the residual method: relative aLM, 20^th percentile of the distribution of residuals as the cutoff point, (RASM), respectively. CSA is a surrogate for force.

RESULTS

We found lower values on RASM (p<0.001), and SMI (p<0.001) compared to controls in SCI and difference in the rate of sarcopenia according to sarcopenia definitions. CSA was significantly decreased in SCI (p<0.001) and correlation with duration of paralysis was weak.

CONCLUSION

Current functional definitions of sarcopenia classify different individuals as sarcopenic. Sarcopenia was more prevalent in SCI. The sensitivity and specificity of using these measurements in SCI remain unclear.

Clinical Impact and Risk Factors for Skeletal Muscle Loss After Complete Resection of Early Non-small Cell Lung Cancer

BACKGROUND

A relationship between sarcopenia diagnosed by skeletal muscle area (SMA) and poor prognosis in cancer patients has recently been reported. This study aimed to clarify the clinical significance of postoperatively decreased SMA in patients with early non-small cell lung cancer (NSCLC).

METHODS

This study selected 101 patients with pathologic stage 1 NSCLC who had undergone pre- and postoperative (~ 1 year) computed tomography scans and lobectomy between 2005 and 2010 at Kyushu University Hospital. The post/pre ratio was defined as the postoperative normalized SMA (cm²/m²) at the 12th thoracic vertebra level divided by the preoperative normalized SMA. The cutoff value for the post/pre ratio was set at 0.9.

RESULTS

The study classified 31 patients (30.7%) as having decreased SMA. Poor performance status (PS) was significantly associated with decreased SMA (p = 0.048). The patients with decreased SMA had a significantly shorter disease-free survival (DFS) (p < 0.001) and overall survival (OS) (p < 0.001) than the other patients. Decreased SMA was found to be an independent prognostic factor for DFS (p = 0.010) and OS (p = 0.0072). The independent risk factors for skeletal muscle loss included poor PS (PS ≥ 1) and obstructive ventilatory impairment [forced expiratory volume (FEV) 1% < 70%].

CONCLUSIONS

Skeletal muscle loss after surgery is significantly associated with postoperative poor outcomes for patients with early NSCLC. Patients with poor PS, obstructive ventilatory impairment, or both need careful support to maintain their skeletal muscle mass. Future prospective studies may clarify whether physical activity and nutritional support improve postoperative prognosis.

Associations of muscle force, power, cross-sectional muscle area and bone geometry in older UK men

BACKGROUND

Ageing is associated with sarcopenia, osteoporosis, and increased fall risk, all of which contribute to increased fracture risk. Mechanically, bone strength adapts in response to forces created by muscle contractions. Adaptations can be through changes in bone size, geometry, and bending strength. Muscle mass is often used as a surrogate for muscle force; however, force can be increased without changes in muscle mass. Increased fall risk with ageing has been associated with a decline in muscle power-which is a measure of mobility. The aims of this study were as follows: (i) to investigate the relationship between muscle parameters in the upper and lower limbs with age in UK men and the influence of ethnicity on these relationships; (ii) to examine the relationships between jump force/grip strength/cross-sectional muscle area (CSMA) with bone outcomes at the radius and tibia.

METHODS

White European, Black Afro-Caribbean, and South Asian men aged 40-79 years were recruited from Manchester, UK. Cortical bone mineral content, cross-sectional area, cortical area, cross-sectional moment of inertia, and CSMA were measured at the diaphysis of the radius and tibia using peripheral quantitative computed tomography. Lower limb jump force and power were measured from a single two-legged jump performed on a ground-reaction force platform. Grip strength was measured using a dynamometer. Associations between muscle and bone outcomes was determined using linear regression with adjustments for age, height, weight, and ethnicity.

RESULTS

Three hundred and one men were recruited. Jump force was negatively associated with age; for every 10 year increase in age, there was a 4% reduction in jump force (P < 0.0001). There was a significant age-ethnicity interaction for jump power (P = 0.039); after adjustments, this was attenuated (P = 0.088). For every 10 year increase in age, grip strength decreased by 11%. Jump force was positively associated with tibial bone outcomes: a 1 standard deviation greater jump force was associated with significantly higher cortical bone mineral content 3.1%, cross-sectional area 4.2%, cortical area 3.4%, and cross-sectional moment of inertia 6.8% (all P < 0.001). Cross-sectional muscle area of the lower leg was not associated with tibial bone outcomes. Both grip strength and CSMA of the arm were positively associated, to a similar extent, with radius diaphyseal bone outcomes.

CONCLUSIONS

Jump force and power are negatively associated with age in UK men. In the lower limb, the measurement of jump force is more strongly related to bone outcomes than CSMA. It is important to consider jump force and power when understanding the aetiology of bone loss and mobility in ageing men.