Impact of supplementation with bicarbonate on lower-extremity muscle performance in older men and women

Summary  

This study describes the impact of bicarbonate treatment for 3 months on net acid excretion (NAE), nitrogen excretion, and muscle performance in older men and women. Bicarbonate reduced NAE, and the decrement was associated with a decrease in nitrogen excretion. Treatment also improved muscle power and endurance in the women.     

Physical function,muscle strength and muscle mass in children on peritoneal dialysis

The aim of this study was to examine the physical function and muscle strength of children on peritoneal dialysis (PD) and to assess whether the muscle structure alterations influence physical function and muscle strength in these children. Twenty-two children on PD and 16 healthy children were enrolled into the study. A 6-min walk distance and gait speed tests were used to evaluate physical performance. Quadriceps muscle strength (QMS) was measured with a hand-held dynamometer. Magnetic resonance imaging was used to determine the cross-sectional area (CSA) and T2 signal intensity of the quadriceps muscle. Significant differences in the performance of these functional tests were found between PD patients and controls. Quadriceps muscle strength was significantly lower in PD patients than in controls. The CSA corrected for the body mass index (CSA/BMI) was not different between groups, whereas T2 signal intensity was significantly higher in PD patients than in the controls. Physical functioning tests and QMS had a close relationship with muscle CSA/BMI and with T2 signal intensity. In conclusion, along with the other previously documented mechanisms, increased fat in muscles may contribute to the decreased physical functioning and muscle strength in PD patients.     

Age-associated declines in muscle mass,strength, power,and physical performance: impact on fear of falling and quality of life

Summary

This 3-year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of life. Our findings reinforce the importance of preserving muscle health with advancing age.

Introduction

The age-associated loss of skeletal muscle quantity and function are critical determinants of independent physical functioning in later life. Longitudinal studies investigating how decrements in muscle components of sarcopenia impact fear of falling (FoF) and quality of life (QoL) in older adults are lacking.

Methods

Twenty-six healthy older subjects (age, 74.1?±?3.7; Short Physical Performance Battery (SPPB) score ≥10) and 22 mobility-limited older subjects (age, 77.2?±?4.4; SPPB score ≤9) underwent evaluations of lower extremity muscle size and composition by computed tomography, strength and power, and physical performance at baseline and after 3-year follow-up. The Falls Efficacy Scale (FES) and Short Form-36 questionnaire (SF-36) were also administered at both timepoints to assess FoF and QoL, respectively.

Results

At 3-year follow-up, muscle cross-sectional area (CSA) (p?<?0.013) and power decreased (p?<?0.001), while intermuscular fat infiltration increased (p?<?0.001). These decrements were accompanied with a longer time to complete 400 m by 22?±?46 s (p?<?0.002). Using linear mixed-effects regression models, declines of muscle CSA, strength and power, and SPPB score were associated with increased FES score (p?<?0.05 for each model). Reduced physical component summary score of SF-36 over follow-up was independently associated with decreased SPPB score (p?<?0.020), muscle CSA (p?<?0.046), and increased 400 m walk time (p?<?0.003).

Conclusions

In older adults with and without mobility limitations, declining muscle mass, strength, power, and physical performance contribute independently to increase FoF, while declines of muscle mass and physical performance contribute to deterioration of QoL. These findings provide further rationale for developing interventions to improve aging muscle health.

     

Decreased muscle strength and quality in older adults with type 2 diabetes: the health, aging, and body composition study

Adequate skeletal muscle strength is essential for physical functioning and low muscle strength is a predictor of physical limitations. Older adults with diabetes have a two- to threefold increased risk of physical disability. However, muscle strength has never been investigated with regard to diabetes in a population-based study. We evaluated grip and knee extensor strength and muscle mass in 485 older adults with diabetes and 2,133 without diabetes in the Health, Aging, and Body Composition study. Older adults with diabetes had greater arm and leg muscle mass than those without diabetes because they were bigger in body size. Despite this, muscle strength was lower in men with diabetes and not higher in women with diabetes than corresponding counterparts. Muscle quality, defined as muscle strength per unit regional muscle mass, was significantly lower in men and women with diabetes than those without diabetes in both upper and lower extremities. Furthermore, longer duration of diabetes (>or=6 years) and poor glycemic control (HbA(1c) >8.0%) were associated with even poorer muscle quality. In conclusion, diabetes is associated with lower skeletal muscle strength and quality. These characteristics may contribute to the development of physical disability in older adults with diabetes.     

肌肉强度和肌肉质量与绝经后女性骨密度的相关性研究

目的探索绝经后女性肌肉强度和肌肉质量与骨密度相关性。方法分析了2014年3月至2017年8月在我院就诊的340名绝经后妇女。使用双能量X射线吸收测定法检测股骨颈和腰椎骨密度(bone mineral density,BMD)、全身骨密度和附肢骨骼肌肌肉量(appendicular skeletal muscle,ASM)。ASM指数(ASMI,kg/m~2)按照ASM(kg)除以高度的平方(m~2)计算。测量握力(kg)作为肌肉力量的指标。结果调整ASMI和年龄后(股骨颈标准化偏回归系数β=0. 105,腰椎=0. 116),握力强度与几个骨骼部位BMD呈显著性正相关(P0. 05)。股骨颈和腰椎骨密度的调整平均值显示出握力强度从最低到最高三分位数的显著增加趋势。本研究结果表明肌肉强度与绝经后妇女肌肉量的几个位点的BMD密切相关。无论肌肉大小如何,肌力强健的绝经后妇女都有健康的骨骼状态。结论绝经后女性骨密度和肌肉强度密切相关,与肌肉质量无明显相关性。     

Undercarboxylated osteocalcin,muscle strength and indices of bone health in older women

We investigated the association between undercarboxylated osteocalcin (ucOC) and lower-limb muscle strength in women over the age of 70 years. The study also aims to confirm the association between bone turnover markers and heel ultrasound measures. A post-hoc analysis using data collected as part of a randomized placebo-controlled trial of vitamin D supplementation. An immunoassay was used to quantify total OC (tOC), with hydroxyapatite pre-treatment for ucOC. We determined associations of absolute and relative (ucOC/tOC; ucOC%) measures of ucOC with lower-limb muscle strength, heel ultrasound measures of speed of sound (SOS) and broadband ultrasound attenuation (BUA), bone turnover markers (BTMs; P1NP and CTx) and the acute phase protein alpha-1-antichymotrypsin (α-ACT). ucOC%, but not absolute ucOC concentration, was positively associated with hip flexor, hip abductor and quadriceps muscle strength (all p < 0.05). ucOC% was negatively associated with α-ACT (β-coefficient = − 0.24, p = 0.02). tOC was positively associated with both P1NP and CTx (p < 0.001). For each per unit increase in tOC (μg/L) there was a corresponding lower BUA, SOS and SI (β-coefficient = − 0.28; − 0.23 and − 0.23, respectively; all p < 0.04). In conclusion, ucOC% is positively associated with muscle strength and negatively associated with α-ACT. These data support a role for ucOC in musculoskeletal interactions in humans. Whilst tOC is associated with bone health, ucOC% and ucOC may also be linked to falls and fracture risk by influencing muscle function.     

Lower extremity muscle strength does not independently predict proximal femur bone mineral density in healthy older adults

The relationship described in the published literature between muscle strength and bone mineral density of older adults is not entirely certain. It is possible that the direct relationship reported in some studies is biased by failing to mathematically account for the biological influence of body weight and body height on both bone mineral density and muscle strength. This study sought to determine if the relationships between measures of lower extremity muscle strength and bone mineral density of the proximal femur are independent of body size (i.e., body height and body weight) in healthy older adults. We recruited 50 older women and 29 older men, all of whom were healthy community dwellers and not involved in resistance training. Quantitative analysis of the isometric strength of the bilateral ankle, knee, and hip joints and assessment of bone mineral density of the proximal femur were conducted. Muscle strength values were adjusted for the influence of body height and body weight using an allometric scaling procedure. The correlations between proximal femur bone mineral density and the unadjusted strength values were weak but statistically significant. After adjusting muscle strength to account for the influence of body height and body weight, the magnitudes of the correlations between bone mineral density and muscle strength diminished substantially and were not significantly different from zero. The results reveal that, for a typical sample of healthy older adults not involved in resistance training, the relationship between maximal isometric muscle strength of lower extremity joints and proximal femur bone mineral density is reliant on body size.     

Sex differences between the relationship of trunk muscle mass and whole body sagittal plane alignment in older adults

BackgroundThis study aimed to clarify sex differences in the relationship between trunk muscle mass, aging, and whole-body sagittal alignment.MethodsSubjects aged 60–89 years who underwent musculoskeletal screening in 2018 were included in the study. Subject demographics, trunk muscle mass (TMM) measured by bioelectrical impedance analysis (BIA), and spinopelvic and lower extremity alignment parameters measured from standing radiographic images were investigated. Additionally, TMM was corrected for BMI (TMM/BMI). The relationship between trunk muscle and whole-body sagittal alignment was analyzed for each age group (young-old group (60–74 years) and old–old group (>75 years)) and sex.ResultsA total of 281 (mean age 75.4 ± 6.7 years, 100 males and 181 females) were enrolled. The trunk muscle mass in both men and women significantly decreased with age. Regarding TMM/BMI, there was no significant difference in men, but there was a significant difference between females in the young-old and old–old groups (p < 0.001). TMM/BMI was significantly correlated with sagittal vertical axis (SVA) and knee flexion angle (KF) in both sexes. In females, TMM/BMI was significantly correlated with thoracic kyphosis in the young-old group, whereas in the old–old group, TMM/BMI was correlated with SVA, PI-LL, and KF.ConclusionsTMM was related to trunk anteverion and lower extremity alignment in both sexes. However, the relationship between TMM on alignment differs between sexes. Thoracic hyperkyphosis in young-old adults indicated a decrease in muscle mass, which may be a sign of future malalignment.     

The effect of intravenous nutrition on muscle mass and exercise capacity in perioperative patients

This study was undertaken to compare the efficacy of four different types of perioperative intravenous nutritional support. Fifty-five patients undergoing routine major surgery were studied. They were prospectively assigned to one of four study groups. Group 1 received formal total parenteral nutrition (90 g amino acids, 3,000 calories as glucose, per day); Group 2, 100 g glucose per day; Group 3, 90 g amino acids per day; and Group 4, peripheral parenteral nutrition (90 g amino acids plus 1,600 calories, 60 percent as fat per day). Group 1 was maintained on therapy for 3 weeks and the other groups for 8 days. Nitrogen balance, maintenance of body cell mass, serum albumin levels, and maintenance of exercise capacity were measured. Patients receiving peripheral parenteral nutrition maintained their nutritional parameters, as did those receiving total parenteral nutrition. These infusions were both markedly superior to those receiving glucose alone or those receiving amino acids alone. Nitrogen balance was not correlated with maintenance of function, but maintenance of body cell mass was correlated with maintenance of exercise capacity (r = 0.66, p less than or equal to 0.01). We conclude that perioperative peripheral parenteral nutrition, in contradistinction to hypocaloric infusions of glucose or amino acids, is capable of maintaining postoperative muscle mass and function close to preoperative levels after major surgery, and in situations of relatively mild surgical stress, approaches the efficacy of total parenteral nutrition in this regard. A significant correlation exists between changes in body cell mass determined from isotope dilution and changes in the exercise capacity of large muscle masses.     

Impact of obstructive airways disease on quality of life in older adults.

BACKGROUND: Obstructive airways disease adversely affects quality of life, although relationships between quality of life and lung function have been shown to be weak. The relationships between the results of a quality of life questionnaire, spirometric tests, and methacholine bronchial challenge were investigated in a population sample of middle aged and elderly people. METHODS: A random population sample of the white population of Central Manchester, UK were contacted by post. Respondents were invited to undergo bronchial challenge with methacholine (Newcastle dosimeter method) and to complete the St George's Respiratory Questionnaire. This self-completed questionnaire quantifies quality of life as three component scores, with higher scores indicating greater impairment of quality of life. RESULTS: Two hundred and twenty seven subjects aged 45-86 years completed the St George's Questionnaire and performed spirometric tests; 190 completed the methacholine challenge. All quality of life scores were higher in subjects with a forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) of < 65%, indicating impaired quality of life in subjects with airways obstruction. There was no relationship between quality of life and age. Multiple regression analysis showed independent relationships between quality of life scores and both baseline FEV1 and bronchial responsiveness. However, the amount of variation in quality of life attributable to variation in FEV1 or bronchial responsiveness was less than 10%. Subgroup analysis indicated that the quality of life score was independently associated with bronchial responsiveness and not FEV1 in subjects aged < 65 years, but with baseline FEV1 and not bronchial responsiveness in older subjects. CONCLUSIONS: Obstructive airways disease significantly impairs quality of life in adults. The reduction in quality of life in these patients is related to both baseline pulmonary function and non-specific bronchial responsiveness. The impact of airways obstruction on quality of life does not decrease with advancing age.     

Relationship between body mass index and spinal pathology in community-dwelling older adults

Purpose

To clarify the relationship between body mass index (BMI) and spinal pathologies including spinal sagittal balance, back extensor strength (BES), paraspinal muscle mass, prevalent vertebral fracture, disc degeneration, Modic changes, low back pain, and quality of life (QOL) in community-dwelling older adults.

Methods

This study included 380 participants (age: ≥ 65 years, male/female: 152/228) from the Shiraniwa Study. Multivariate nonlinear regression analysis was used to investigate the relationship between BMI and sagittal vertical axis (SVA), BES, paraspinal muscle mass, visual analog scale (VAS) for low back pain, Oswestry Disability Index (ODI), and EuroQoL-5 Dimension (EQ5D) score after adjusting for sex, age, Hospital Anxiety and Depression Scale score, and Charlson Comorbidity Index. In addition, multiple logistic regression analysis was used to investigate the association between BMI and prevalent vertebral fracture, disc degeneration, and Modic changes.

Results

BMI was significantly correlated with SVA, BES, paraspinal muscle mass, VAS, ODI, and EQ5D score. The increase in BMI was associated with the deterioration of all outcomes, which accelerated when the BMI increased from approximately 22–23 kg/m². Moreover, overweight/obesity was significantly correlated with disc degeneration and Modic changes.

Conclusion

Increased BMI is significantly associated with spinal pathologies such as SVA, BES, paraspinal muscle mass, VAS, QOL, disc degeneration, and Modic changes. The findings suggest that measures for controlling overweight and obesity among older adults can play an important role in the prevention and treatment of spinal pathologies.

     

Evaluating the relationship between muscle and bone modeling response in older adults

Bone modeling, the process that continually adjusts bone strength in response to prevalent muscle-loading forces throughout an individual's lifespan, may play an important role in bone fragility with age. Femoral stress, an index of bone modeling response, can be estimated using measurements of DXA derived bone geometry and loading information incorporated into an engineering model. Assuming that individuals have adapted to habitual muscle loading forces, greater stresses indicate a diminished response and a weaker bone. The purpose of this paper was to evaluate the associations of lean mass and muscle strength with the femoral stress measure generated from the engineering model and to examine the extent to which lean mass and muscle strength account for variation in femoral stress among 2539 healthy older adults participating in the Health ABC study using linear regression. Mean femoral stress was higher in women (9.51, SD = 1.85 Mpa) than in men (8.02, SD = 1.43 Mpa). Percent lean mass explained more of the variation in femoral stress than did knee strength adjusted for body size (R² = 0.187 vs. 0.055 in men; R² = 0.237 vs. 0.095 in women). In models adjusted for potential confounders, for every percent increase in lean mass, mean femoral stress was 0.121 Mpa lower (95% CI: − 0.138, − 0.104; p < 0.001) in men and 0.139 Mpa lower (95% CI: − 0.158, − 0.121; p < 0.001) in women. The inverse association of femoral stress with lean mass and with knee strength did not differ by category of BMI. Results from this study provide insight into bone modeling differences as measured by femoral stress among older men and women and indicate that lean mass may capture elements of bone's response to load.     

Effects of limb-length discrepancy on gait economy and lower-extremity muscle activity in older adults.

BACKGROUND: The amount of limb-length discrepancy necessary to adversely affect gait parameters in older adults is unknown, with information being largely anecdotal. This investigation was conducted to determine the effects of limb-length discrepancy on gait economy and lower-extremity muscle activity in older adults. METHODS: Forty-four men and women ranging in age from fifty-five to eighty-six years with no evidence of limb-length discrepancy of >1 cm participated in the study. Subjects walked on a treadmill at a self-selected normal walking pace with artificial limb-length discrepancies of 0, 2, 3, and 4 cm applied in a randomly selected order. Indirect calorimetry was used to measure oxygen consumption and minute ventilation. Electromyography was used to measure muscle activity of the right and left quadriceps femoris, plantar flexors, gluteus maximus, and gluteus medius. Heart rate, the rating of perceived exertion, and frequency of gait compensation patterns were also measured. RESULTS: There was a significant increase in oxygen consumption and the rating of perceived exertion with 2, 3, and 4-cm artificial limb-length discrepancies; a significant increase in heart rate, minute ventilation, and quadriceps activity in the longer limb with 3 and 4-cm artificial limb-length discrepancies; and a significant increase in plantar flexor activity in the shorter limb with a 4-cm artificial limb-length discrepancy compared with the same parameters with no artificial limb-length discrepancy. CONCLUSIONS: Both oxygen consumption and the rating of perceived exertion were greater with a 2-cm artificial limb-length discrepancy than they were with no artificial limb-length discrepancy. There appears to be a breakpoint between 2 and 3 cm of artificial limb-length discrepancy in older adults with regard to the effects on most other physiological parameters. A 3-cm artificial limb-length discrepancy is likely to induce significant quadriceps fatigue in the longer limb. Elderly patients with substantial pulmonary, cardiac, or neuromuscular disease may have difficulty walking with a limb-length discrepancy as small as 2 cm.     

Impaired bone microarchitecture at the distal radius in older men with low muscle mass and grip strength: The STRAMBO study

The aim was to study the association between bone microarchitecture and muscle mass and strength in older men. Volumetric bone mineral density (vBMD) and bone microarchitecture were assessed in 810 men aged ≥60 years at the distal radius by high‐resolution peripheral computed tomography (HR‐pQCT). Areal bone mineral density (aBMD) and appendicular muscle mass (ASM) were assessed by dual‐energy X‐ray absorptiometry (DXA). Relative ASM of the upper limbs (RASM‐u.l.) was calculated as ASM of the upper limbs/(height)². Grip strength was measured by dynanometry. In multivariable models, men in the lowest RASM‐u.l. quartile had lower cross‐sectional area (CSA), cortical area (Ct.Ar), cortical thickness (Ct.Th), and trabecular area (Tb.Ar) at distal radius compared with men in the highest quartile. The trends remained significant after adjustment for grip strength. Men in the lowest quartile of the normalized grip strength (grip strength/[height]²) had lower aBMD, total vBMD, Ct.Ar, Ct.Th, Tb.vBMD, and Tb.N, and higher Tb.Sp and Tb.Sp.SD. The associations for Ct.Ar, total vBMD, Ct.Th, Tb.vBMD, and Tb.Sp remained significant after adjustment for RASM‐u.l. In the models including RASM‐u.l. and normalized grip strength, CSA and Tb.Ar were associated with RASM‐u.l. but not with the strength. Lower Ct.Th, Tb.vBMD, and Tb.N were associated with lower grip strength but not with RASM‐u.l. Lower Ct.Ar was associated with lower grip strength and with lower RASM‐u.l. In conclusion, in older men, low RASM‐u.l. and low grip strength are associated with poor cortical and trabecular microarchitecture partly independently of each other, after adjustment for confounders. © 2013 American Society for Bone and Mineral Research