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PubMed2006

Muscle strength, body composition, and physical activity in women receiving chemotherapy for breast cancer.

There is evidence to suggest that treatment of breast cancer with chemotherapy can induce metabolic changes in skeletal muscle. Women undergoing treatment for breast cancer with certain chemotherapeutic agents can experience declines in lean body mass and muscle strength and a subsequent increase in body weight. These alterations not only can lead to declines in physical function but also predispose women to weight-related chronic illness. Excess body weight may also play a role in the development or recurrence of breast cancer. There is evidence that physical exercise may improve body composition and enhance muscular endurance, flexibility, and quality of life (QOL) in women with breast cancer. While studies of aerobic, resistance, and combinations of aerobic and resistance exercise for women with breast cancer have been conducted, most studies employed supervised aerobic exercise sessions. Few studies have examined the role of resistance exercise or the combination of resistance and aerobic exercise in maintaining or increasing muscle strength while preserving lean body mass in this population. The relatively small sample sizes and short duration of physical activity interventions in previous studies make it difficult to detect dose responses to exercise training. Physical activity interventions with larger sample sizes and of longer duration are necessary to achieve long-term health outcomes. Physical activity interventions that include the older or more obese women with breast cancer are also needed, as this population may be most at risk of functional decline and the development of chronic illness. Interventions appropriate for women treated for breast cancer who have comorbid disease are also needed. Newer, more intense chemotherapy regimens may induce a differential effect on muscle strength and body composition. However, the role of physical activity during dose-dense chemotherapy protocols has not been established.

Antineoplastic Agents↗

PubMed1979

Method for measurement of maximal isometric muscle strength with special reference to the fingers.

A method for measurement of the maximal isometric muscle strength in the fingers is presented. Details of the apparatus designed for avoidance of hysteresis in mechanical components on measurement of low strengths are given. The measurement of low strengths is described. The measurement procedure is simple both for examiner and for the subject. Values for finger muscle strength in normal persons are presented.

Equipment and Supplies↗

PubMed1988

Effect of chronic renal failure on respiratory muscle strength.

In 10 patients with chronic renal failure (CRF), undergoing hemodialysis, we studied respiratory muscle strength and endurance. The data obtained was compared with those acquired from 10 age-, sex-, weight- and height-matched normal volunteers. Maximal static inspiratory pressures (PImax) measured at residual volume and maximal static expiratory pressure (PEmax) measured at total lung capacity were significantly lower in the CRF group, 58.2 +/- (SD)24.9 and 50.8 +/- (SD)24.2% of predicted, respectively (p less than 0.005, p less than 0.01). There was a significant correlation between PImax and PEmax (r = 0.827, p less than 0.001), indicating similar involvement of both inspiratory and expiratory muscle groups. Maximal voluntary ventilation (MVV), although 84.4% of the predicted value in the CRF group, was significantly lower than in the control group, where it was 114% of predicted (p less than 0.001). MVV also correlated significantly with PImax and PEmax (r = 0.764, p less than 0.001 and r = 0.807, p less than 0.001, respectively). All but one CRF patient had elevated erum inorganic phosphorus levels, and a significant correlation was found between the serum inorganic phosphorus levels and PImax and PEmax (r = 0.718, p less than 0.001). These data indicate that there is an impairment of respiratory muscle strength and endurance in patients with CRF which may predispose the patient to respiratory muscle fatigue.

Adult↗

PubMed1992

Respiratory muscle strength in hyperthyroidism before and after treatment.

We undertook this study to investigate respiratory muscle strength in relation to thyroid function in 20 thyrotoxic patients and in a group of 20 normal subjects matched for age and sex. Global respiratory muscle strength was assessed by measuring mouth pressure during maximal static inspiratory (PImax) and expiratory (PEmax) efforts. We also measured VC, FVC, and FEV1 as well as thyroid-related hormones (T3, T4, TSH). Measurements were made once in normal subjects and twice in thyrotoxic patients, before and 3 months after medical treatment. Our results showed that both maximal pressures were significantly reduced (p less than 0.0001) before treatment in thyrotoxic patients in relation to the mean values of the normal subjects (p less than 0.0001), and they increased significantly (p less than 0.0003) after treatment. Lung volumes were significantly reduced (p less than 0.0001) before and increased significantly (p less than 0.008) after treatment. The ratio FEV1/FVC did not change. A statistically significant linear relationship was found when PImax of patients with thyrotoxicosis before treatment and of normal subjects were plotted against thyroid hormones (T3, T4) (r = -0.746 and r = -0.745, respectively, p less than 0.001). Similarly, a statistically significant linear relationship was found between PEmax and T3 and T4 (r = -0.837 and r = -0.838, respectively, p less than 0.001). No relationship was found between maximal pressures and TSH. Finally, a significant linear relationship was found between PImax and PEmax (r = 0.872, p less than 0.001). Our results confirm that in thyrotoxicosis respiratory muscle weakness occurs that affects both inspiratory and expiratory muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

Neck muscle strength across the sagittal and coronal planes: an isometric study.

OBJECTIVE: To determine the maximal isometric strength of neck muscles across different anatomical positions in the body sagittal and coronal planes. DESIGN: A descriptive study involving maximal isometric strength measurements of the cervical musculature in extension, flexion, and left and right lateral bending. Before measurements, the new device was tested for reliability. BACKGROUND: The literature contains only a few studies on cervical musculature strength assessment. Of these, measurement methods have displayed weak reliability. No studies existed reporting neck strength at various positions in the body coronal plane. METHODS: A new device incorporating local population anthropometry was developed for neck strength assessment on an isokinetic dynamometer. The device's repeatability attributes at measuring the strength of functionally different groups of neck muscles were first evaluated. The isometric apparatus was next used to determine the maximal strength of the cervical musculature of 17 healthy volunteers at different anatomical positions across the body sagittal and coronal motion planes. RESULTS: The results showed good intratester repeatability for intraday and day-to-day studies for all measured parameters. Strength values demonstrated that extensor muscles yielded the greatest torque and that flexor muscles provided the least torque. Linear regression analyses showed strong association of isometric strength with anatomical positions in the two body planes. CONCLUSIONS: Maximal isometric strength of neck muscles in four directions was quantified. Cervical musculature strength levels vary in discernible patterns with head-neck positions and contraction directions. RELEVANCE: Knowledge of normative values of neck muscle strength is essential for designing and implementing appropriate rehabilitation programmes. Results from the present study contribute to such literature.

Adult↗

PubMed1998

High thigh muscle strength but not bone mass in young horseback-riding females.

To evaluate whether the type of weight-bearing loading subjected to the skeleton during horseback-riding was associated with differences in bone mass and muscle strength of the thigh, we investigated bone mass and isokinetic muscle strength in 20 female horse riders (age 17.9 +/- 0.6 years) who were riding 7.0 +/- 3.4 hours/week, and 20 nonactive females (age 17.8 +/- 1.1 years). The groups were matched according to age, weight, and height. Areal bone mineral density was measured in total body, head, lumbar spine, right femoral neck, Ward's triangle, and trochanter, the whole dominant and nondominant humerus, and in specific sites in the right femur diaphysis, distal femur, proximal tibia, and tibia diaphysis using dual X-ray absorptiometry. Isokinetic concentric and eccentric peak torque of the quadricep and hamstring muscles were measured using an isokinetic dynamometer. There were no significant differences in bone mass between the horseback riders and nonactives at any site measured. The horse riders were significantly (P < 0.05-0.01) stronger in concentric hamstrings strength at 90 degrees/second and 225 degrees/second and in eccentric quadricep and hamstring strength at 90 degrees/second. Horseback riding in young females is associated with a high muscle strength of the thigh, but not with a high bone mass.

Adolescent↗

PubMed1995

Impairment of lung volumes and respiratory muscle strength in adult patients with growth hormone deficiency.

Little is known of the respiratory function in patients with growth hormone (GH) deficiency. The aim of the present study was to evaluate lung volumes and respiratory muscle strength in patients diagnosed as GH deficient in childhood. Ten patients diagnosed as GH deficient in childhood and ten healthy subjects entered the study. For each subject the evaluation of respiratory function followed the same standard approach, consisting of respiratory muscle strength assessment, recording of flow-volume curves, measurement of static lung volumes and lung diffusing capacity. Both maximal inspiratory and expiratory mouth pressures were decreased in GH deficiency. Vital capacity, N2 functional residual capacity and total lung capacity were significantly reduced when compared to healthy subjects. Conversely, the residual volume and diffusing lung capacity to CO did not show any significant change. No significant change of percentage forced expiratory volume in 1 s/forced vital capacity ratio was observed. The decrease of respiratory mouth pressures was not correlated to the decrease of lung volumes. In conclusion, the results of this study show that adult patients affected with childhood onset GH deficiency suffer from impairment of ventilatory function and a decrease of respiratory muscle pressures, probably due to reduction of respiratory muscle strength.

Adult↗

PubMed2005

A comparison of perineometer to brink score for assessment of pelvic floor muscle strength.

OBJECTIVE: The Brink scale is a commonly used digital assessment of pelvic floor muscle strength. The Peritron perineometer, a compressible vaginal insert that records pressure in centimeters of water, offers an objective method for this evaluation. This study evaluates the inter- and intrarater reliability of perineometry measurements and correlates those values with Brink scores. STUDY DESIGN: Subjects were prospectively enrolled and underwent pelvic floor muscle strength assessment by 2 examiners each using a perineometer and the Brink scale. Perineometer measurements of maximum pressure, average pressure, and total duration were recorded for 3 consecutive pelvic floor muscle contractions (Kegels). The Brink assessment was performed by placing 2 fingers vaginally during a single Kegel contraction. Brink scores consisted of 3 separate 4-point rating scales for pressure, vertical finger displacement, and duration. The order of the examiners and the 2 assessment methods were randomized, and each examiner was blinded to the results of the other. Pearson and Spearman correlation coefficients were used for analysis as appropriate. Repeated-measures analysis of variance was used to assess intrarater reliability between repeated perineometer measurements. RESULTS: One hundred women were consecutively enrolled and completed the study. Interrater reliability for the perineometer maximum squeeze pressure (r = 0.88) and baseline resting pressure (r = 0.78) was high. Maximum squeeze pressure correlation was unaffected by the presence or absence of estrogen (r = 0.89 versus r = 0.85), nulliparity versus parity (0.85 versus 0.88), or genital hiatus 4 or greater or less than 4 (r = 0.96 versus r = 0.86). Total Brink score and each individual submeasurement showed good correlations (total: r = 0.68; pressure: r = 0.68; displacement: r = 0.58; duration: r = 0.44). The correlation between maximum squeeze pressure and total Brink score during the first and second exams was good (r = 0.68 versus r = 0.71). For intrarater reliability, there were no significant differences among the 3 maximum squeeze pressures recorded during the first exam (P = .11), but for the second exam, the first squeeze was significantly stronger than the successive 2 (P = .009) attempts. CONCLUSION: Perineometer measurements of pelvic floor muscle contractions show very good inter- and intrarater reliability. The Brink total and pressure scores had a slightly lower interrater reliability. Variables such as estrogen status, parity, and genital hiatus did not appear to affect correlation. There was good correlation between the maximum perineometer pressure and the total Brink score, suggesting that these 2 methods of assessment have similar levels of reproducibility. Additionally, the perineometer demonstrated good short-term test-retest reliability.

Adult↗

PubMed1984

The influence of variations in muscle fibre composition on muscle strength and cross-sectional area in untrained males.

The force produced by a maximum voluntary isometric contraction of the knee-extensor muscles was measured in a group of fifteen healthy young male volunteers. All subjects were untrained at the time of the study. The cross-sectional area of the knee-extensor muscles was measured at the mid-thigh level using computed tomography. Skeletal muscle samples were obtained by needle biopsy from the mid-point of m. vastus lateralis of the stronger leg of each subject. Samples were mounted, frozen and sectioned for histochemical analysis. On the basis of the pH dependent lability of the myosin ATP-ase reaction, fibres were classified as Type I, Type IIA or Type II B. Using computerized planimetry, muscle fibre cross-sectional areas were measured on serial sections stained for succinate dehydrogenase activity. As previously described, muscle strength (maximum voluntary contraction) was correlated with the muscle cross-sectional area (r = 0.70, P less than 0.01). The ratio of strength (in N) to cross-sectional area (in cm2) was 8.92 +/- 1.01 (mean +/- S.D.) with a wide range of values, from 7.09 to 10.85. Muscle fibre composition of m. vastus lateralis in these subjects was 46.1 +/- 10.5% Type I, 42.8 +/- 11.4% Type IIA and 11.1 +/- 9.7% Type IIB. After correction for differences in the cross-sectional areas of the different fibre types, the proportions of total area occupied by the different fibre types were: 43.6 +/- 11.9% Type I, 46.4 +/- 13.1% Type IIA and 10.0 +/- 9.1% Type IIB. No relationship was observed to exist between muscle strength and muscle fibre composition. Similarly, the muscle strength/cross-sectional area ratio was not related to the proportions of the different fibre types present or to the fraction of the total cross-sectional area occupied by the different fibre types. From the results it can be concluded that there is no difference in the force per unit area which can be generated by the different muscle fibre types present in human skeletal muscle. Variations in muscle fibre composition between individuals cannot, therefore, account for the large variations observed in the ratio of strength to muscle cross-sectional area.

Adult↗

PubMedDate not supplied

Implications of expiratory muscle strength training for rehabilitation of the elderly: Tutorial.

With age, physical functions decline, which influences respiratory performance. One of the physical changes associated with aging is sarcopenia, a reduction in muscle strength and power. Sarcopenia has been extensively studied in the elderly with regard to limb function but less with regard to respiratory function. Elderly individuals experience reduced muscle mass and strength in respiratory musculature, which may hinder the ability to generate adequate expiratory driving force for both ventilatory and nonventilatory activities. Increasing expiratory muscle strength may enhance an elderly individual's ability to generate and maintain the expiratory driving force critical to cough, speak, and swallow. Previous studies demonstrate that expiratory muscle strength training (EMST) improves ventilatory and nonventilatory functions. This paper discusses the potential impact that EMST can have on the rehabilitation of respiratory muscle decline, particularly in the elderly. This tutorial reviews an EMST paradigm, its physiological underpinnings, and its potential outcomes.

Aged↗

PubMed2006

[A comparison of respiratory muscle strength, pulmonary function tests and endurance in patients with early and late stage ankylosing spodylitis].

BACKGROUND: Ankylosing spondylitis (AS) is a multisystemic disease in which pulmonary function is altered owing mainly to the restriction of chest wall involvement. A restrictive ventilatory defect has been extensively reported. This has been suggested to be a consequence of reduced mobility of the thoracic cage. Respiratory function in AS shows a typical restrictive pattern but pulmonary compliance, diffusion capacity, and arterial blood gases are normal. OBJECTIVE: The objective of the present study was to compare pulmonary function tests (PFT), respiratory muscle strength (MIP, MEP) and endurance (MVV) in early and late AS. METHODS: A total of 35 patients (30 males, 5 females) took part, all of whom met the New York criteria for AS. Patients were divided into two groups for the comparison of early (disease duration <10 years, 20 patients) and late (disease duration >10 years, 15 patients) manifestations in pulmonary function tests, respiratory muscle strength and endurance, dyspnea score, chest expansion, and BASFI score. In addition, 21 healthy controls were compared with the AS patients. Measurement of chest expansion was performed in all subjects. Pulmonary function tests were performed by spirometry. Respiratory muscle strength was evaluated by a mouth pressure meter (MPM). Functional status was assessed by BASFI in all AS patients. RESULTS: There was no significant difference in body mass index between the groups. The FVC and FEV(1) were significantly lower in late AS (p=0.003, p=0.03, restrictive ventilatory defect ). Chest expansion was significantly lower in late AS (p<0.05). There was no significant difference for MIP or MEP values between late AS, early AS and the controls (p>0.05). Endurance (MVV) was significantly lower in late AS patients (p=0.05). Although the BASFI and dyspnea scores were higher in late AS, they did not reach significant levels. In addition, age was negatively correlated with MIP and MEP in late AS (r=-0.733; p=0.02, r=-0.667; p=0.05). CONCLUSION: This study demonstrates that FVC and FEV(1) (hallmarks of a restrictive pattern), MVV (endurance) and chest expansion are especially involved in long-standing AS. Therefore, improvement of the thoracic cage should be taken into consideration, especially in early AS. These patients should be encouraged to make regular respiratory exercises for preventing the limitation of chest expansion and also improving cardiopulmonary fitness and respiratory endurance.

Adult↗

PubMed2001

Effects of whey protein and resistance exercise on body cell mass, muscle strength, and quality of life in women with HIV.

OBJECTIVE: To determine the effects of whey protein, resistance exercise, and combined protein and exercise treatment on body cell mass (BCM), muscle strength, and quality of life (QOL) in HIV-infected women with reduced BCM. DESIGN AND SETTING: Prospective, randomized, controlled trial at a university hospital in New York City. METHODS: A volunteer sample of 30 HIV-infected women were randomized to whey protein (PRO), progressive resistance exercise (PRE), or combined treatment (PRO-PRE) for 14 weeks after a 6-week control period. The main outcome measures were body weight, BCM, skeletal muscle, fat mass, muscle strength, and QOL. RESULTS: There were no significant changes in BCM, strength, or QOL during the control period. PRO patients gained 3.6 kg (P = 0.001), and 2.5 kg fat (P = 0.002) with no change in BCM (0.5 kg; P = 0.07) or skeletal muscle (0.6 kg; P = 0.12). The PRE group increased BCM (0.74 kg;P = 0.03) and skeletal muscle (1.2 kg; P < 0.001) and decreased fat (1.7 kg; P = 0.02). PRO-PRE increased BCM (0.61 kg; P = 0.01) without change in skeletal muscle (0.6 kg; P = 0.30). Strength increased for both exercise groups (range, 40.6-95.3%; P < 0.001). The QOL physical activity score improved for PRE (P = 0.02) and worsened for PRO (P = 0.01). CONCLUSIONS: Resistance exercise significantly increased BCM, muscle mass, muscle strength, and QOL in HIV-infected women with reduced BCM. Whey protein had little effect on BCM accrual. Combined protein and exercise did not increase BCM in excess of gains achieved by exercise alone.

Adult↗

PubMed2005

Insulin resistance and muscle strength in older persons.

BACKGROUND: The functional consequences of an age-related insulin resistance (IR) state on muscle functioning are unknown. Because insulin is needed for adequate muscle function, an age-related insulin-resistant state may also be a determining factor. We evaluated the relationship between IR and handgrip muscle strength in men and women from a large population-based study (n = 968). METHODS: The degree of IR was evaluated by the homeostasis model assessment (HOMA) and muscle strength was assessed using handgrip. RESULTS: Simple sex-stratified correlations demonstrated that, in men, body mass index-adjusted handgrip strength correlated positively with physical activity (r = 0.321; p < .001), muscle area (r = 0.420; p < .001), muscle density (r = 0.263; p = .001), plasma albumin (r = 0.156; p = .001), insulin-like growth factor-1 (r = 0.258; p < .001), calcium (r = 0.140; p = .006), and testosterone (r = 0.325; p < .001) concentrations, whereas a negative association was found for age (r = -0.659; p < .001) and myoglobin plasma levels (r = -0.164; p =.001). In women, body mass index-adjusted handgrip strength correlated positively with physical activity (r = 0.280; p < .001), muscle area (r = 0.306; p < .001), muscle density (r = 0.341; p = .001), plasma albumin (r = 0.140; p =.001), and insulin-like growth factor-1 (r = 0.300; p < .001), whereas a negative association was found for age (r = -0.563; p < .001), myoglobin levels (r = -0.164; p = .001), and IR (r = -0.130; p = .04). CONCLUSIONS: Sex-stratified analyses adjusted for multiple confounders showed that the relationship between IR and handgrip strength was found significant in women, whereas it was negligible and not significant in men.

Adult↗

PubMed1998

Type of physical activity, muscle strength, and pubertal stage as determinants of bone mineral density and bone area in adolescent boys.

The present study was conducted to evaluate the influence of different types of weight-bearing physical activity, muscle strength, and puberty on bone mineral density (BMD, g/cm2) and bone area in adolescent boys. Three different groups were investigated. The first group consisted of 12 adolescent badminton players (age 17.0 +/- 0.8 years) training for 5.2 +/- 1.9 h/week. The second group consisted of 28 ice hockey players (age 16.9 +/- 0.3 years) training for 8.5 +/- 2.2 h/week. The third group consisted of 24 controls (age 16.8 +/- 0.3 years) training for 1.4 +/- 1.4h/week. The groups were matched for age, height, and pubertal stage. BMD, bone mineral content (BMC, g), and the bone area of the total body, lumbar spine, hip, femur and tibia diaphyses, distal femur, proximal tibia, and humerus were measured using dual-energy X-absorptiometry. When adjusting for the difference in body weight between the groups, the badminton players were found to have significantly higher BMD (p < 0.05) of the trochanter and distal femur compared with the ice hockey players despite a significantly lower weekly average training. The badminton players had higher BMD compared with the control with the control group at all weight-bearing BMD sites, except at the diaphyses of the femur and tibia and lumbar spine. The independent predictors of bone density were estimated by adjusting BMC for the bone area in a multivariate analysis among all subjects (n = 64). Accordingly, the bone density of all sites except the spine was significantly related to muscle strength and height, and the bone density of the total body, neck, trochanter, distal femur, and proximal tibia was significantly related to type of physical activity (beta = 0.09-0.33, p < 0.05). The bone area values at different sites were strongly related to muscle strength and height and less strongly related to the type of physical activity and pubertal stage. In conclusion, it seems that during late puberty in adolescent boys the type of weight-bearing physical activity is an important determinant of bone density, while the bone area is largely determined by parameters related to body size. The higher BMD at weight-bearing sites in badminton players compared with ice hockey players, despite significantly less average weekly training, indicates that physical activity including jumps in unusual directions has a great osteogenic potential.

Absorptiometry, Photon↗

PubMed2000

Anaerobic power and muscle strength in young hemophilia patients.

PURPOSE: The purpose of this study was to evaluate muscle strength and anaerobic power in young boys with hemophilia compared with healthy boys. METHODS: Thirteen boys with severe hemophilia (H) (mean (+/- SD) age = 12.0 +/- 3.17 yr) and 16 control (C) boys (age = 11.9 +/- 2.8 yr) performed elbow and knee flexion and extension on the Biodex System II dynamometer at two angular velocities. They also performed a Wingate Anaerobic Test (WAnT) for the legs and for the arms. All H subjects received prophylactic factor VIII treatment in the 24 h pretesting, and no test was performed in the presence of hemorrhage. RESULTS: C were consistently stronger than H in all dynamic strength measures (e.g., elbow flexors: 0.47 +/- 0.15 vs 0.36 +/- 0.08 N x m x kg(-1) for C and H, respectively, P < 0.05). Anaerobic mean power was also higher in C compared with H in both upper and lower extremities (arms: 3.08 +/- 0.99 vs 2.22 +/- 0.46 W x kg(-1) for C and H, respectively; legs: 6.94 +/- 1.62 vs 5.54 +/- 1.03 W x kg(-1) for C and H, respectively, P < 0.05). Upper and lower extremity strength, as well as anaerobic power, increased with age in C but not in H. By using the Godin Leisure-Time Exercise Questionnaire, H were found to be much less active, especially in intense activities, compared with C. CONCLUSION: Children and adolescents with hemophilia are characterized by lower muscle strength and anaerobic power compared with age-matched controls. This may be related to their lower leisure-time activity.

Adolescent↗

PubMed2006

Longitudinal changes in muscle strength and mass after acute stroke.

BACKGROUND: Reduced mobility after stroke may cause a loss of muscle mass which may, in theory, contribute to disability. We investigated longitudinal changes in muscle strength, lean cross-sectional area and muscle mass in all limbs after acute stroke. METHODS: We recruited 17 patients within 72 h of hospital admission and measured (a) hand grip strength, (b) knee extensor strength and (c) arm and leg lean cross-sectional area on 6 occasions over 6 months. Appendicular and total muscle mass (dual-energy X-ray absorptiometry) were measured at 3 weeks and 6 months. RESULTS: There was no significant change over time in the strength, lean cross-sectional area and muscle mass of the arms or legs. We noted that muscle strength was substantially lower in all limbs compared with population norms. CONCLUSION: We found no evidence of a decline in muscle strength or mass in any limb after the stroke, which could have been attributed to reduced mobility. The observed muscle weakness in the ipsilateral side may have pre-dated the stroke.

Absorptiometry, Photon↗

PubMed2000

Muscle strength and body mass index as long-term predictors of mortality in initially healthy men.

BACKGROUND: Muscle weakness, low body weight, and chronic diseases are often observed in the same people; however, the association of muscle strength with mortality, independent of disease status and body weight, has not been elucidated. The aim was to assess hand grip strength as a predictor of all-cause mortality within different levels of body mass index (BMI) in initially disease-free men. METHODS: Mortality was followed prospectively over 30 years. Maximal hand grip strength tests and BMI assessments were done at baseline in 1965 to 1970. The participants were 6040 healthy men aged 45 to 68 years at baseline living on Oahu, Hawaii. RESULTS: The death rates per 1000 person years were 24.6 in those with BMI <20, 18.5 in the middle BMI category, and 18.0 in those with BMI > or = 25. For grip strength tertiles, the mortality rates were 24.8 in the lowest, 18.5 in the middle, and 14.0 in the highest third. In Cox regression models, within each tertile of grip strength, BMI showed only minimal effect on mortality. In contrast, in each category of BMI there was a gradient of decreasing mortality risk with increasing grip strength. Among those with BMI <20, the adjusted relative risks (RRs) of mortality over 30 years were 1.36 (95% confidence interval 1.14-1.63) for those in the lowest third of strength at baseline, 1.27 (1.02-1.58) in the middle, and 0.92 (0.66-1.29) in the highest third. Correspondingly, for those with BMI 20-24.99, the RRs of death were 1.25 (1.08-1.45), 1.14 (1.00-1.32), and 1.0 (reference) in the lowest, middle, and highest third of grip strength, respectively. In those with BMI > or =25, the RRs were 1.39 (1.16-1.65) in the lowest, 1.27 (1.08-1.49) in the middle, and 1.14 (0.98-1.32) in the highest third of grip strength. Models were adjusted for age, education, occupation, smoking, physical activity, and body height. CONCLUSIONS: In healthy middle-aged men, long-term mortality risk was associated with grip strength at baseline, independent of BMI. The possible interpretation of the finding is that early life influences on muscle strength may have long-term implications for mortality. Additionally, higher strength itself may provide greater physiologic and functional reserve that protects against mortality.

Aged↗

PubMed2002

Nutritional status and muscle strength in patients with emphysema and severe alpha(1)-antitrypsin deficiency.

BACKGROUND: The association between emphysema and weight loss is well known. Severe alpha(1)-antitrypsin deficiency is an important risk factor for the development of emphysema. STUDY OBJECTIVE: To study nutritional status and muscle strength in patients with severe alpha(1)-antitrypsin deficiency and emphysema. METHODS: Fifteen alpha(1)-antitrypsin-deficient patients with emphysema (7 men) and 18 healthy control subjects (9 men) were included in the study. Total body protein (TBP) was measured by in vivo neutron activation analysis of nitrogen. Lean body mass (LBM) was estimated from measurement of total body potassium. In analogy with body mass index (BMI), TBP index and LBM index were calculated as TBP/height squared and LBM/height squared, respectively. Respiratory muscle strength was studied by maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax), and skeletal muscle strength by handgrip test. Plasma albumin, transthyretin, and retinol-binding protein concentrations were analyzed as biochemical markers of nutritional status. RESULTS: In the alpha(1)-antitrypsin-deficient individuals, lung function test results were consistent with severe chronic airway obstruction, whereas the healthy control subjects had normal lung function. No significant differences were found in age, body weight, or BMI between the groups. TBP (p < 0.05), TBP index (p < 0.001), LBM index (p < 0.05), and plasma concentration of transthyretin (p < 0.01) were significantly lower in the patients than in the control subjects. There was a significant correlation between TBP and LBM (p < 0.001), and between TBP and body weight (p < 0.001). In the male subgroup, PImax (p < 0.05) and PEmax (p < 0.05) were significantly lower in the patients than in the control subjects. In the female subgroup, handgrip strength was significantly lower in the patients than in the control subjects (p < 0.05). Body weight was significantly correlated with handgrip test (p < 0.05) in the male patients. In the female patients, body weight was significantly correlated with PImax (p < 0.05), LBM with PEmax (p < 0.05), and LBM with handgrip test (p < 0.01). CONCLUSION: Reduced TBP and plasma transthyretin concentration in alpha(1)-antitrypsin-deficient patients with emphysema may indicate early signs of malnutrition.

Adult↗