Age-associated changes in skeletal muscles and their effect on mobility: an operational diagnosis of sarcopenia

The association of dementia with upper arm and waist circumference in seven low- and middle-income countries: the 10/66 cross-sectional surveys

BACKGROUND

Weight loss in dementia contributes to morbidity and mortality but the distribution of anthropometric change and its consistency between populations are less clear. Our aim was to investigate and compare the associations of dementia with waist and upper arm circumference in elders from seven low- and middle-income nations.

METHODS

Cross-sectional surveys were conducted of 15,022 residents aged 65 years and older in Cuba, Mexico, Venezuela, Peru, Dominican Republic, China, and India. Dementia was assessed using a cross-culturally validated algorithm, and anthropometric measurements were taken. Associations with dementia and dementia severity (clinical dementia rating scale) were investigated in linear regression models, with fixed-effects meta-analyses used to investigate between-country heterogeneity.

RESULTS

Dementia and increased dementia severity were both associated with smaller arm and waist circumferences with little evidence of confounding by sociodemographic and health status. Associations between dementia/clinical dementia rating and arm circumference were homogeneous between countries (Higgins I(2) 0% and 7%, respectively), whereas those with waist circumference were more heterogeneous (Higgins I(2) 67% and 62%, respectively).

CONCLUSIONS

Although cross-sectional, our findings are consistent with prospective observations of weight loss in dementia and suggest loss of both muscle and fat-the former being consistent across different settings and the latter being more context dependent.

Sarcopenic obesity in the elderly and strategies for weight management

Sarcopenia is a multifactorial age-related condition associated with a sedentary lifestyle and protein intakes during weight loss that are inadequate to maintain muscle mass. Sarcopenic obesity in the elderly is associated with a loss of independence and metabolic complications and represents a major public health challenge in individuals over the age of 65 years. It is likely that age-related losses of muscle mass and coincident increases in fat mass could be reduced through regular resistance exercise combined with adequate protein intake to maintain muscle mass. It has been established that increased protein intake will maintain muscle mass during calorie-restricted diets to a greater extent than usual protein intake. Other strategies, including the use of high-protein meal replacements or supplementation with specific ergogenic or branched-chain amino acids, may be beneficial.

Constructing an index of physical fitness age for Japanese elderly based on 7-year longitudinal data: sex differences in estimated physical fitness age

A standardized method for assessing the physical fitness of elderly adults has not yet been established. In this study, we developed an index of physical fitness age (fitness age score, FAS) for older Japanese adults and investigated sex differences based on the estimated FAS. Healthy elderly adults (52 men, 70 women) who underwent physical fitness tests once yearly for 7 years between 2002 and 2008 were included in this study. The age of the participants at the beginning of this study ranged from 60.0 to 83.0 years. The physical fitness tests consisted of 13 items to measure balance, agility, flexibility, muscle strength, and endurance. Three criteria were used to evaluate fitness markers of aging: (1) significant cross-sectional correlation with age; (2) significant longitudinal change with age consistent with the cross-sectional correlation; and (3) significant stability of individual differences. We developed an equation to assess individual FAS values using the first principal component derived from principal component analysis. Five candidate fitness markers of aging (10-m walking time, functional reach, one leg stand with eyes open, vertical jump and grip strength) were selected from the 13 physical fitness tests. Individual FAS was predicted from these five fitness markers using a principal component model. Individual FAS showed high longitudinal stability for age-related changes. This investigation of the longitudinal changes of individual FAS revealed that women had relatively lower physical fitness compared with men, but their rate of physical fitness aging was slower than that of men.

Prevalence of sarcopenia in healthy community-dwelling elderly in an urban area of Barcelona (Spain)

INTRODUCTION

The purpose of this study was to evaluate the prevalence of sarcopenia in a cohort of healthy community-dwelling elderly in an urban area in Barcelona (Spain) for native benchmarks and compare them with those published in other geographical areas.

MATERIAL AND METHODS

We prospectively evaluated a series of 200 healthy elderly in the community with preserved functional capacity and absence of cognitive impairment. We performed a comprehensive geriatric assessment and determined anthropometric data, muscle mass (MM) and the muscle mass index (MMI). Assessment of muscle mass was performed by bioelectrical impedance analysis (BIA). The cut-off point for defining sarcopenia MMI was established as less than 2 SD of the mean of a reference group comprising 220 healthy volunteers (20-42 years) in the same area. Results were compared with studies undertaken in the USA, France and Taiwan.

RESULTS

The cut-off points obtained were 8.31 Kg/m(2) for men and 6.68 Kg/m2 for women, being similar to those observed in France and Taiwan but different from the USA. The prevalence of sarcopenia observed was 33% for elderly women and 10% for males. On comparison of the prevalence of sarcopenia in the four populations, we observed some differences, particularly in males.

CONCLUSIONS

We have defined reference values for sarcopenia, determined by BIA, in our setting. We also observed a remarkable prevalence of sarcopenia in the healthy elderly community, especially in females, showing some differences from those in other geographical regions.

Sexual dimorphism modulates the impact of cancer cachexia on lower limb muscle mass and function

BACKGROUND & AIMS

There is a sparsity of data on the impact of cachexia on human muscle function. This study examined the relationship between cachexia, quality of life and the mass/function/mechanical quality of lower limb skeletal muscle in gastrointestinal cancer patients.

METHODS

Quadriceps strength and lower limb power were measured in 54 patients with gastrointestinal cancer (n = 24 ≥ 10% weight-loss) and 18 healthy controls. Quadriceps cross-sectional area was measured in 33/54 patients and in all controls using MRI. Muscle mechanical quality was defined as quadriceps strength/unit quadriceps cross-sectional area. Quality of life was assessed using the EORTC QLQ-C30. Patients with weight-loss ≥ 10% were classified as cachectic.

RESULTS

In male cachectic patients, quadriceps strength (p = 0.003), lower limb power (p = 0.026), quadriceps cross-sectional area (p = 0.019) and muscle quality (p = 0.008) were reduced compared with controls. In female cachectic patients, quadriceps strength (p = 0.001) and muscle quality (p = 0.001) were reduced compared with controls. Physical function (p = 0.013) and fatigue (p = 0.004) quality of life scores were reduced in male cachectic compared with non-cachectic patients, but not in females.

CONCLUSIONS

Muscle quality is reduced in cancer patients. The degree of impairment of lower limb muscle mass, quality and function and the impact on quality of life varies with weight-loss and sex.

A multi-cohort study of polymorphisms in the GH/IGF axis and physical capability: the HALCyon programme

BACKGROUND

Low muscle mass and function have been associated with poorer indicators of physical capability in older people, which are in-turn associated with increased mortality rates. The growth hormone/insulin-like growth factor (GH/IGF) axis is involved in muscle function and genetic variants in genes in the axis may influence measures of physical capability.

METHODS

As part of the Healthy Ageing across the Life Course (HALCyon) programme, men and women from seven UK cohorts aged between 52 and 90 years old were genotyped for six polymorphisms: rs35767 (IGF1), rs7127900 (IGF2), rs2854744 (IGFBP3), rs2943641 (IRS1), rs2665802 (GH1) and the exon-3 deletion of GHR. The polymorphisms have previously been robustly associated with age-related traits or are potentially functional. Meta-analysis was used to pool within-study genotypic effects of the associations between the polymorphisms and four measures of physical capability: grip strength, timed walk or get up and go, chair rises and standing balance.

RESULTS

Few important associations were observed among the several tests. We found evidence that rs2665802 in GH1 was associated with inability to balance for 5 s (pooled odds ratio per minor allele = 0.90, 95% CI: 0.82-0.98, p-value = 0.01, n = 10,748), after adjusting for age and sex. We found no evidence for other associations between the polymorphisms and physical capability traits.

CONCLUSION

Our findings do not provide evidence for a substantial influence of these common polymorphisms in the GH/IGF axis on objectively measured physical capability levels in older adults.

Dynapenia and aging: an update

In 2008, we published an article arguing that the age-related loss of muscle strength is only partially explained by the reduction in muscle mass and that other physiologic factors explain muscle weakness in older adults (Clark BC, Manini TM. Sarcopenia =/= dynapenia. J Gerontol A Biol Sci Med Sci. 2008;63:829-834). Accordingly, we proposed that these events (strength and mass loss) be defined independently, leaving the term "sarcopenia" to be used in its original context to describe the age-related loss of muscle mass. We subsequently coined the term "dynapenia" to describe the age-related loss of muscle strength and power. This article will give an update on both the biological and clinical literature on dynapenia-serving to best synthesize this translational topic. Additionally, we propose a working decision algorithm for defining dynapenia. This algorithm is specific to screening for and defining dynapenia using age, presence or absence of risk factors, a grip strength screening, and if warranted a test for knee extension strength. A definition for a single risk factor such as dynapenia will provide information in building a risk profile for the complex etiology of physical disability. As such, this approach mimics the development of risk profiles for cardiovascular disease that include such factors as hypercholesterolemia, hypertension, hyperglycemia, etc. Because of a lack of data, the working decision algorithm remains to be fully developed and evaluated. However, these efforts are expected to provide a specific understanding of the role that dynapenia plays in the loss of physical function and increased risk for disability among older adults.

Absolute strength and loss of strength as predictors of mobility decline in older adults: the InCHIANTI study

BACKGROUND

Theoretical definitions of sarcopenia traditionally emphasize age-related loss of muscle strength; however, most analyses of the association between strength and mobility examine strength at a single time point. This study sought to identify sex-specific cutpoints for muscle strength and power (at one time point) and 3-year changes in strength and power that would maximize prediction of 3-year mobility decline.

METHODS

Longitudinal analysis of 934 adults aged ≥65 years enrolled in the Invecchiare in Chianti study was conducted. Grip strength, knee extension strength, and lower extremity power were measured at baseline and 3 years postenrollment. Mobility function (gait speed and self-reported mobility disability) was measured at 3 and 6 years postenrollment. Classification and regression tree analysis was used to predict mobility decline from Years 3 to 6.

RESULTS

Men with knee extension strength <19.2 kg and grip strength <39.0 kg had clinically meaningful declines in gait speed of .24 m/s. Furthermore, men with power <105 W were nearly nine times more likely to develop incident mobility disability (likelihood ratio = 8.68; 95% confidence interval = 3.91, 19.44). Among women, knee extension strength <18.0 kg was associated with a minimal gait speed decline of 0.06 m/s, and women with leg power <64 W were three times more likely to develop incident mobility disability (likelihood ratio = 3.01; 95% confidence interval = 1.79, 5.08). Three-year changes in strength and power did not predict mobility decline in either sex.

CONCLUSIONS

Findings suggest that strength and power measured at one time point are more predictive of mobility decline than 3-year changes and that low strength and power are particularly powerful risk factors in men.

Long-term determinants of muscle strength decline: prospective evidence from the 22-year mini-Finland follow-up survey

OBJECTIVES

To examine long-term changes in handgrip strength and the factors predicting handgrip strength decline.

DESIGN

Longitudinal cohort study with 22 years of follow-up.

SETTING

Population-based Mini-Finland Health Examination Survey in Finland.

PARTICIPANTS

Nine hundred sixty-three men and women aged 30 to 73 at baseline.

MEASUREMENTS

Handgrip strength was measured using a handheld dynamometer at baseline and follow-up. Information on potential risk factors, namely lifestyle and chronic conditions, and their changes throughout the follow-up were based on health interviews.

RESULTS

Based on linear mixed-effect models, midlife physically strenuous work, excess body weight, smoking, cardiovascular disease, hypertension, diabetes mellitus, and asthma predicted muscle strength decline over 22 years of follow-up (P < .05 for all). In addition, pronounced weight loss, becoming physically sedentary, persistent smoking, incident coronary heart disease, other cardiovascular disease, diabetes mellitus, chronic bronchitis, chronic back syndrome, long-lasting cardiovascular disease, hypertension, and asthma were associated with accelerated handgrip strength decline (P < .05 for all).

CONCLUSION

Lifestyle and physical health earlier in life determine rate of muscle strength decline in old age. Efforts should be made to recognize persons at risk in a timely manner and target early interventions to middle-aged persons to slow down muscle strength decline and prevent future functional limitations and disability.

Force-velocity characteristics of the knee extensors: an indication of the risk for physical frailty in elderly women

OBJECTIVES

To examine the relationship between muscle strength, speed of movement, muscle mass (MM), and functional performance in elderly women and to determine optimal threshold values below which physical frailty occurs.

DESIGN

Survey.

SETTING

University-based laboratory.

PARTICIPANTS

Institutionalized women (N=123; mean age, 79.67 ± 5.2y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Force-velocity characteristics of the knee extensors were evaluated by using isometric, isokinetic, and ballistic tests on a motor-driven dynamometer. Isometric (ISOM) strength, dynamic strength, maximal speed of movement (SoM, unloaded), and speed of movement with standardized resistance of 20% (S(20)), 40% (S(40)), and 60% (S(60)) of the isometric maximum were recorded. MM of the upper leg was determined by using computed tomography. The modified Physical Performance Test (mPPT) was used to assess functional performance.

RESULTS

Force-velocity characteristics (r varied from .31-.68) and MM (r=.41) correlated significantly with functional performance (P<.05). In a forward stepwise regression model, only SoM and ISOM strength remained independently associated with mPPT score (R(2)=.49), with SoM accounting for most of the variance. The threshold value that optimally differentiates between women with mild (mPPT score, 25-31) or without (mPPT score ≥32) physical frailty was 350°/s for SoM and 1.46N m/kg for ISOM strength. Sensitivity and specificity ranged from 74% to 77% and 71% to 77%, respectively.

CONCLUSIONS

SoM is a key component in the onset of functional difficulties in elderly women. Exercise interventions specifically targeting muscle power (by including exercises at high velocities) thus might be crucial to prevent functional decline.

Are current definitions of sarcopenia applicable for older Chinese adults?

This study aims to explore whether the current definitions of sarcopenia are applicable to the older Chinese population. Participants were 783 Chinese adults recruited from four regions in Mainland China: Jinan, Guangzhou, Xi'an, and Chengdu. Body composition was measured by dual energy x-ray absorptiometry. Handgrip strength, body weight, and height were measured by trained technicians, and demographic data were collected through questionnaires. Relative appendicular skeletal muscle, skeletal muscle index (SMI=100 × skeletal muscle mass/ body mass) and residuals methods were applied to identify sarcopenia. Compared with young adults, no significant decrease was found in the relative appendicular skeletal muscle (ASM/height2) in older adults. If the criterion of two standard deviations below the mean value of ASM/height2 in young adults is used, none of older adults in this study could be diagnosed with sarcopenia. In addition, compared with the ASM/height2 and residuals methods, SMI shows higher discriminating power in the identifying persons with low handgrip strength. The data suggest that ASM/height2 method may not be appropriate for diagnosis of sarcopenia in Chinese population. However, whether SMI is a better choice remains inconclusive. Prospective studies are needed to clearly define sarcopenia in Chinese population.

Mild thyroid hormone excess is associated with a decreased physical function in elderly men

INTRODUCTION

In the adult, subclinical hyperthyroidism (Shyper) may alter skeletal muscle mass and strength. However, whether these effects are present in elderly subjects is not known. We explored the relationship between mild hyperthyroidism and physical function in a population-based sample of older persons.

METHODS

In a cross-sectional analysis, calf muscle cross-sectional area (CMA), handgrip strength, nerve conduction velocity (NCV), and Short Physical Performance Battery (SPPB) scores were compared between 364 euthyroid (Eut) and 28 Shyper men as well as between 502 Eut and 39 Shyper women. In a longitudinal analysis, we evaluated the relationship between baseline plasma TSH, FT3 and FT4 and the 3-year change in SPPB score in 304 men and 409 women who were euthyroid at enrolment.

RESULTS

At the cross-sectional analysis, Shyper men, but not women, had a significantly (p = 0.02) lower SPPB score than Eut controls, although with comparable CMA, grip strength and NCV, and were more likely to have poor physical performance (odds ratio = 2.97, p < 0.05). Longitudinal analysis showed that in Eut men higher baseline FT4 was significantly (p = 0.02) predictive of a lower SPPB score at the 3-year follow-up.

CONCLUSION

Even a modest thyroid hormone excess is associated with a reduced physical function in elderly men.

Reference values for hand grip strength, muscle mass, walking time, and one-leg standing time as indices for locomotive syndrome and associated disability: the second survey of the ROAD study

BACKGROUND

We established reference values for hand grip strength, muscle mass, walking time, and one-leg standing time as indices reflecting components of locomotive syndrome and associated disability using a large-scale population-based sample from the second survey of the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) cohort.

METHODS

We measured the above-mentioned indices in 2,468 individuals ≥ 40 years old (826 men, 1,642 women; mean age 71.8 years) during the second visit of the ROAD study. Disability was defined as certified disability according to the long-term care insurance system through public health centres of each municipality.

RESULTS

Mean values for hand grip strength (weaker side), muscle mass of the thighs, walking time for 6 m at the usual pace, and the fastest pace for men were 32.7 kg, 7.0 kg, 5.6 s, and 3.7 s, respectively, and those for women were 20.8 kg, 5.2 kg, 5.9 s, and 4.1 s, respectively. The median values for one-leg standing time (weaker side) were 14 s for men and 12 s for women. The prevalence of disability in men aged 65-69, 70-74, 75-79, and ≥ 80 was 0.0, 1.0, 6.3, and 8.8%, respectively, and in women was 3.4, 3.5, 9.2, and 14.7%, respectively. There were significant associations between the presence of disability and walking time for 6 m at the usual pace and at the fastest pace, and between the presence of disability and walking speed.

CONCLUSIONS

We established reference values for indices reflecting components of locomotive syndrome, and identified significant associations between walking ability and disability.

Grip strength and functional balance in community-dwelling older women

Background: Effective detection and treatment of balance impairment in older people is a matter of clinical urgency. 4 screening tool for impaired balance is required, as is clarity regarding the role of muscle strength in balance control.

Methods: This observational study examined the relationship between grip strength and balance in 40 community-dwelling women aged 65-95 years. Measures included grip strength, Functional Reach test, Single Leg Stance Test, Timed Up and Go test and the Berg Balance Scale. Correlation analyses were used to investigate relationships between the variables.

Findings: Significant correlations were found between grip strength and each of the balance measures. The strongest correlation (r=0.55, P<0.001) was found between right grip strength and the Berg Balance Scale. The weakest correlation (r=-0.36, P=0.012) was between left grip strength and the Timed Up and Go test. Grip strength accounted for only 14%-31% of the variance in balance test scores

Conclusions: The association between grip strength and balance was not sufficiently robust for grip strength to be recommended as a screening tool for balance impairment in older people.

Non-invasive muscle contraction assay to study rodent models of sarcopenia

Background

Age-related sarcopenia is a disease state of loss of muscle mass and strength that affects physical function and mobility leading to falls, fractures, and disability. The need for therapies to treat age-related sarcopenia has attracted intensive preclinical research. To facilitate the discovery of these therapies, we have developed a non-invasive rat muscle functional assay system to efficiently measure muscle force and evaluate the efficacy of drug candidates.

Methods

The lower leg muscles of anesthetized rats are artificially stimulated with surface electrodes on the knee holders and the heel support, causing the lower leg muscles to push isometric pedals that are attached to force transducers. We developed a stimulation protocol to perform a fatigability test that reveals functional muscle parameters like maximal force, the rate of fatigue, fatigue-resistant force, as well as a fatigable muscle force index. The system is evaluated in a rat aging model and a rat glucocorticoid-induced muscle loss model

Results

The aged rats were generally weaker than adult rats and showed a greater reduction in their fatigable force when compared to their fatigue-resistant force. Glucocorticoid treated rats mostly lost fatigable force and fatigued at a higher rate, indicating reduced force from glycolytic fibers with reduced energy reserves.

Conclusions

The involuntary contraction assay is a reliable system to assess muscle function in rodents and can be applied in preclinical research, including age-related sarcopenia and other myopathy.

The impact of behavioral intervention on obesity mediated declines in mobility function: implications for longevity

A primary focus of longevity research is to identify prognostic risk factors that can be mediated by early treatment efforts. To date, much of this work has focused on understanding the biological processes that may contribute to aging process and age-related disease conditions. Although such processes are undoubtedly important, no current biological intervention aimed at increasing health and lifespan exists. Interestingly, a close relationship between mobility performance and the aging process has been documented in older adults. For example, recent studies have identified functional status, as assessed by walking speed, as a strong predictor of major health outcomes, including mortality, in older adults. This paper aims to describe the relationship between the comorbidities related to decreased health and lifespan and mobility function in obese, older adults. Concurrently, lifestyle interventions, including diet and exercise, are described as a means to improve mobility function and thereby limit the functional limitations associated with increased mortality.

Age-related differences in lower extremity tissue compartments and associations with physical function in older adults

The lower extremities are important to performing physical activities of daily life. This study investigated lower extremity tissue composition, i.e. muscle and fat volumes, in young and older adults and the relative importance of individual tissue compartments to the physical function of older adults. A total of 43 older (age 78.3±5.6 years) and 20 younger (age 23.8±3.9 years) healthy men and women participated in the study. Older participants were further classified as either high- (HF) or low-functioning (LF) according to the Short Physical Performance Battery (SPPB). Magnetic resonance images were used to determine the volumes of skeletal muscle, subcutaneous fat (SAT), and intermuscular fat (IMAT) in the thigh (femoral) and calf (tibiofibular) regions. After adjusting for the sex of participants, younger participants had more femoral muscle mass than older adults (p<0.001 for between group differences) as well as less femoral IMAT (p=0.008) and tibiofibular IMAT (p<0.001). Femoral muscle was the only tissue compartment demonstrating a significant difference between the two older groups, with HF participants having 31% more femoral muscle mass than LF participants (mean difference=103.0±34.0 cm(3); p=0.011). In subsequent multiple regression models including tissue compartments and demographic confounders, femoral muscle was the primary compartment associated with both SPPB score (r(2)=0.264, p=0.001) and 4-meter gait speed (r(2)=0.187, p=0.007). These data suggest that aging affects all lower extremity compartments, but femoral muscle mass is the major compartment associated with physical function in older adults.

Muscle strength and BMI as predictors of major mobility disability in the Lifestyle Interventions and Independence for Elders pilot (LIFE-P)

BACKGROUND

Muscle weakness and obesity are two significant threats to mobility facing the increasing number of older adults. To date, there are no studies that have examined the association of strength and body mass index (BMI) on event rates on a widely used performance measure of major mobility disability.

METHODS

This study was a secondary analysis of a randomized controlled trial in which sedentary functionally limited participants (70-89 years, Short Physical Performance Battery ≤ 9) who were able to complete a 400-m walk test at baseline were randomized to a physical activity or health education intervention and reassessed for major mobility disability every 6 months for up to 18 months. We evaluated whether baseline grip strength and BMI predicted failure to complete the 400-m walk test in 15 minutes or less (major mobility disability).

RESULTS

Among N = 406 participants with baseline measures, lower grip strength was associated with an increased risk for developing major mobility disability, with and without covariate adjustment (p < .01): The hazard ratio (95% confidence interval) for the lowest versus high sex-specific quartile of grip strength was 6.11 (2.24-16.66). We observed a U-shaped relationship between baseline BMI and the risk of developing major mobility disability, such that the risk for participants with a BMI of 25-29 kg/m(2) was approximately half that of participants with BMI less than 25 or 30 kg/m(2) or more (p = .04 in fully adjusted analyses).

CONCLUSIONS

Our data highlight the importance of muscle weakness, low BMI, and obesity as risk factors for major mobility disability in older adults. Being overweight may be protective for major mobility disability.

Sarcopenia and obesity

Four body composition phenotypes exist in older adults: normal, sarcopenic, obese, and a combination of sarcopenic and obese. There is no consensus, however, on the definitions and classifications of these phenotypes and their etiology and consequences continue to be debated. The lack of standard definitions, particularly for sarcopenia and sarcopenic obesity, creates challenges for determining prevalence across different populations. The etiology of these phenotypes is multifactorial with complex covariate relationships. This review focuses on the current literature addressing the classification, prevalence, etiology, and correlates of sarcopenia, obesity, and the combination of sarcopenia and obesity, referred to as sarcopenic obesity.

The lipid accumulation product is associated with increased mortality in normal weight postmenopausal women

Lipid accumulation product (LAP) is an emerging cardiovascular risk factor, which is calculated from waist circumference (WC) and triglyceride (TG) levels. The aim of this study was to elucidate the relationship between LAP and cardiovascular mortality as well as the presence of type 2 diabetes with respect to gender-specific differences. We determined WC and fasting TG levels and the cardiovascular and metabolic phenotypes coronary artery disease (CAD), hypertension, metabolic syndrome, and diabetes mellitus in 2,279 men and 875 postmenopausal women who were routinely referred to coronary angiography. The LAP was calculated as (WC (cm)--65) × (TG (mmol/l)) for men and as (WC (cm)--58) × (TG (mmol/l)) for women. LAP levels were independently associated with congestive heart failure mortality in all postmenopausal women and with all-cause mortality in diabetic postmenopausal women but not in men. Multivariable-adjusted hazard ratios (with 95% confidence intervals) for all-cause, cardiovascular, and congestive heart failure mortality in the third compared to the first LAP tertile were 4.28 (1.94-9.44; P < 0.001), 3.47 (1.28-9.40; P = 0.015), and 10.77 (1.21-95.88; P = 0.033), respectively, in normal weight postmenopausal women, whereas no significant associations were found in men. LAP levels were highly associated with type 2 diabetes in all subjects, postmenopausal women, and men. High LAP values are predictive of mortality independently of other cardiovascular risk factors in normal weight and diabetic postmenopausal women but not in men. Type 2 diabetes (T2DM) was highly associated with LAP in women and men. Our study validates an inexpensive and simple risk profiling that may allow identifying postmenopausal women at high cardiovascular risk.

Effects of high-intensity resistance training on strength, mobility, balance, and fatigue in individuals with multiple sclerosis: a randomized controlled trial

BACKGROUND AND PURPOSE

Resistance exercise via negative, eccentrically induced work (RENEW) has been shown to be associated with improvements in strength, mobility, and balance in multiple clinical populations. However, RENEW has not been reported for individuals with multiple sclerosis (MS).

METHODS

Nineteen individuals with MS (8 men, 11 women; age mean = 49 ± 11 years; Expanded Disability Status Scale [EDSS] mean = 5.2 ± 0.9) were randomized into either standard exercise (STAND) or standard exercise and RENEW training (RENEW) for 3×/week for 12 weeks. Outcome measures were lower extremity strength (hip/knee flexion and extension, ankle plantar and dorsiflexion, and the sum of these individual values [sum strength]); Timed Up and Go (TUG), 10-m walk, self-selected pace (TMWSS) and maximal-pace (TMWMP), stair ascent (S-A) and descent (S-D) and 6-Minute Walk Test (6MWT), Berg Balance Scale (BBS), Fatigue Severity Scale (FSS).

RESULTS

No significant time effects or interactions were observed for strength, TUG, TMWSS, TMWMP, or 6MWT. However, the mean difference in sum strength in the RENEW group was 38.60 (representing a 15% increase) compared to the sum strength observed in the STAND group with a mean difference of 5.58 (a 2% increase). A significant interaction was observed for S-A, S-D, and BBS as the STAND group improved whereas the RENEW group did not improve in these measures.

DISCUSSION AND CONCLUSIONS

Contrary to results in other populations, the addition of eccentric training to standard exercises did not result in significantly greater lower extremity strength gains in this group of individuals with MS. Further this training was not as effective as standard exercise alone in improving balance or the ability to ascend and descend stairs. Following data collection, reassessment of required sample size indicates we were likely underpowered to detect strength differences between groups.

Strength and power training did not modify cardiovascular responses to aerobic exercise in elderly subjects

Resistance training increases muscle strength in older adults, decreasing the effort necessary for executing physical tasks, and reducing cardiovascular load during exercise. This hypothesis has been confirmed during strength-based activities, but not during aerobic-based activities. This study determined whether different resistance training regimens, strength training (ST, constant movement velocity) or power training (PT, concentric phase performed as fast as possible) can blunt the increase in cardiovascular load during an aerobic stimulus. Older adults (63.9 ± 0.7 years) were randomly allocated to: control (N = 11), ST (N = 13, twice a week, 70-90% 1-RM) and PT (N = 15, twice a week, 30-50% 1-RM) groups. Before and after 16 weeks, oxygen uptake (VO(2)), systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) were measured during a maximal treadmill test. Resting SBP and RPP were similarly reduced in all groups (combined data = -5.7 ± 1.2 and -5.0 ± 1.7%, respectively, P < 0.05). Maximal SBP, HR and RPP did not change. The increase in measured VO(2), HR and RPP for the increment in estimated VO(2) (absolute load) decreased similarly in all groups (combined data = -9.1 ± 2.6, -14.1 ± 3.9, -14.2 ± 3.0%, respectively, P < 0.05), while the increments in the cardiovascular variables for the increase in measured VO(2) did not change. In elderly subjects, ST and PT did not blunt submaximal or maximal HR, SBP and RPP increases during the maximal exercise test, showing that they did not reduce cardiovascular stress during aerobic tasks.

Fat mass limits lower-extremity relative strength and maximal walking performance in older women

The purpose of this study was to determine if excess fat negatively affects relative strength and walking gait performance in overweight, older women. Twenty-five older women (65-80 yr) were separated into normal weight (BMI<25 kg m(-2), n=11) and overweight groups (BMI 25 ≥ kg m(-2), n=14). Strength and rate of torque development (RTD) of the knee extensors and flexors, ankle plantarflexors and dorsiflexors were measured. Participants walked at standard and maximal speeds during which muscle activation, spatiotemporal and kinetic gait variables were measured. Relative to mass, overweight older women had 24% lower maximal torque and 38% lower RTD than normal weight women. Maximal walking speed was slower in overweight (1.25±0.22 vs. 1.54±0.25 m s(-1), P=0.004) and was correlated to strength (r=0.53, P<0.01) and fat mass (r=-0.65, P=0.001). At maximal speed, overweight had 11% lower vertical ground reaction force relative to mass, 8% slower stride rate, 12% shorter strides, 13% longer foot-ground contact times, 21% longer double-limb support times, 65% greater knee extensor and 78% greater plantarflexor activation (P<0.05). Overweight, older women demonstrated altered gait and reduced walking performance related to poor relative strength and rate of torque development of lower-extremity muscles.

Lipogenic regulators are elevated with age and chronic overload in rat skeletal muscle

AIM

Both muscle mass and strength decline with ageing, but the loss of strength far surpasses what is projected based on the decline in mass. Interestingly, the accumulation of fat mass has been shown to be a strong predictor of functional loss and disability. Furthermore, there is a known attenuated hypertrophic response to skeletal muscle overload with ageing. The purpose of this study was to determine the effect of 28 days of overload on the storage of intramuscular triglycerides (IMTG) and metabolic regulators of lipid synthesis in young and old skeletal muscle.

METHODS

The phosphorylation and expression of essential lipogenic regulators were determined in the plantaris of young (YNG; 6-month-old) and aged (OLD; 30-month-old) rats subjected to bilateral synergist ablation (SA) of two-thirds of the gastrocnemius muscle or sham surgery.

RESULTS

We demonstrate that age-induced increases in IMTG are associated with enhancements in the expression of lipogenic regulators in muscle. We also show that the phosphorylation and concentration of the 5'AMP-activated protein kinase (AMPK) isoforms are altered in OLD. We observed increases in the expression of lipogenic regulators and AMPK signalling after SA in YNG, despite no increase in IMTG. Markers of oxidative capacity were increased in YNG after SA. These overload-induced effects were blunted in OLD.

CONCLUSION

These data suggest that lipid metabolism may be altered in ageing skeletal muscle and is unaffected by mechanical overload via SA. By determining the role of increased lipid storage on skeletal muscle mass during ageing, possible gene targets for the treatment of sarcopenia may be identified.

Body composition (sarcopenia) in obese patients: implications for care in the intensive care unit

The study of body composition is a rapidly evolving science. In today's environment, there is a great deal of interest in assessing body composition, especially in the obese subject, as a guide to clinical and nutrition interventions. There are some strikingly different compartments of body composition between the obese and the lean patient. We do have the ability to measure body composition accurately, although these techniques can be labor intensive and expensive. The recognition of patients with sarcopenic obesity has identified a potential high-risk patient population. These body composition abnormalities may have even greater importance in the intensive care patient.

Grip work estimation during sustained maximal contraction: validity and relationship with dependency and inflammation in elderly persons

OBJECTIVES

To validate muscle endurance estimation and to examine relationships with dependency and inflammation in elderly persons.

DESIGN

Cross sectional validation and explorative study.

SETTING

Hospitalized geriatric patients and community-dwelling controls.

PARTICIPANTS

91 elderly patients (aged 83±5 years), 100 elderly controls (aged 74±5 years) and 100 young controls (aged 23±3 years).

MEASUREMENTS

Grip strength (GS) was recorded continuously during sustained maximal contraction until exhaustion. Fatigue resistance (FR) was expressed as the time during which GS drops to 50% of its maximum. Grip work (GW) was estimated as GW=GS*0.75*FR, and compared to the measured GW. In the elderly participants, relationships (controlling for age and physical activity) of GS, FR, GW and GW corrected for body weight (GW/BW) with dependency (Katz-scale) and inflammation (circulating IL-6 and TNF-alpha) were analyzed.

RESULTS

Excellent correlation between estimated and measured GW was found (r=0.98, p<0.001). The method error coefficient of variance was 10% for all participants; 7% for all elderly and 8% for young controls. Better GS, FR, GW and GW/BW was significantly related with less dependency (all p<0.05 or p<0.01, except for FR in the male) and with lower circulating IL-6 (all p<0.05 or p<0.01, except for GS in both genders). Higher IL-6 was significantly related to worse dependency (p<0.01). No significant relationships with TNF-alpha were found.

CONCLUSION

GW estimation is a valid parameter reflecting muscle endurance in elderly persons presenting diverse clinical conditions. GW is significantly related to both dependency and circulating IL-6, and is a promising outcome parameter in comprehensive geriatric assessment.

Safe neuromuscular electrical stimulator designed for the elderly

A stimulator for neuromuscular electrical stimulation (NMES) was designed, especially suiting the requirements of elderly people with reduced cognitive abilities and diminished fine motor skills. The aging of skeletal muscle is characterized by a progressive decline in muscle mass, force, and condition. Muscle training with NMES reduces the degradation process. The discussed system is intended for evoked muscle training of the anterior and posterior thigh. The core of the stimulator is based on a microcontroller with two modular output stages. The system has two charge-balanced biphasic voltage-controlled stimulation channels. Additionally, the evoked myoelectric signal (M-wave) and the myokinematic signal (surface acceleration) are measured. A central controller unit allows using the stimulator as a stand-alone device. To set up the training sequences and to evaluate the compliance data, a personal computer is connected to the stimulator via a universal serial bus. To help elderly people handle the stimulator by themselves, the user interface is kept very simple. For safety reasons, the electrode impedance is monitored during stimulation. A comprehensive compliance management with included measurements of muscle activity and stimulation intensity enables a scientific use of the stimulator in clinical trials.

[Association of physical functions with leisure-time, household, and occupational physical activity in community-dwelling older adults]

AIM

The study objective was to cross-sectionally examine the relationships among leisure-time, household, and occupational physical activity with physical functions in Japanese older adults.

METHODS

We randomly enrolled 189 community-dwelling older adults, aged 65 to 85 years, as subjects from the Basic Resident Register of Kasama City, Ibaraki prefecture. Physical activity was assessed by the Physical Activity Scale for the Elderly. Analysis of covariance was performed to determine the relationships between physical activity and physical functions, after adjustment for age and sex.

RESULTS

Leisure-time physical activity significantly correlated with one-leg balance with eyes open, sit and reach, timed standing test from along sitting position on the floor, functional reach, 5-repetition sit-to-stand, timed up and go, 5-m habitual walk, choice stepping reaction time, and power in sit-to-stand tests. Household physical activity was significantly related to 5-repetition sit-to-stand and ability in sit-to-stand. Total (leisure-time plus household plus occupational) activity was significantly correlated with one-leg balance with eyes open, functional reach, and power in sit-to-stand tests. Post-hoc testing indicated that the levels of physical functions were higher in the subjects of the third tertile than in those of the first or second tertile. No difference was found in physical functions between the first and second tertile.

CONCLUSION

Leisure-time physical activity was related to many physical functions. Household physical activity was also related to lower-extremity functions. Our data suggest that medium- or high-level physical activity may be necessary for older adults to maintain their physical functions.

Clinical trials on sarcopenia: methodological issues regarding phase 3 trials

Phase 3 trials estimate the effectiveness of an intervention to prevent, delay the onset of, or treat sarcopenia. Participants should have sarcopenia or present a sarcopenia risk profile. Control group should be characterized by the best standard of clinical care. This article further develops issues on sarcopenia definition, target population, primary and secondary end points, duration of the trials, muscle mass assessment, strength and physical performance assessment, and control of possible confounders. The challenges to conduct phase 3 trials in the elderly should not offset the opportunities for the development of new strategies to counteract sarcopenia and prevent late-life disability.

Clustering of metabolic abnormalities among obese patients and mortality after percutaneous coronary intervention

Although current literature demonstrates metabolic abnormalities are associated with mortality, obese patients who tend to have more metabolic abnormalities paradoxically have lower overall mortality rates compared to their normal-weight counterparts. In this study, we examined the prevalence of metabolic abnormality clustering and its relation to mortality in obese and normal-weight patients after percutaneous coronary intervention (PCI). Patients (n = 9,673) undergoing elective PCI from October 2003 through December 2006 at a single urban hospital were categorized by body mass index (BMI) levels of 18.5 to 24.9, 25.0 to 29.9, 30.0 to 34.9, and ≥35 kg/m(2) and by number of metabolic abnormalities possessed (hypertension, impaired fasting glucose/diabetes, triglycerides ≥150 mg/dl, high-density lipoprotein cholesterol < 40 mg/dl, and C-reactive protein ≥2.0 mg/L). All-cause mortality was assessed through June 30, 2007. Mean age of patients was 65.9 years and 66% were men. Prevalences of 4 or 5 metabolic abnormalities were 12%, 18%, 24%, and 31% in patients with BMI levels of 18.5 to 24.9, 25.0 to 29.9, 30 to 34.9, and ≥35 kg/m(2), respectively. In patients with BMI of 30.0 to 34.9 kg/m(2), hazard ratios (95% confidence intervals) for mortality associated with 2, 3, and 4 to 5 metabolic abnormalities versus 0 to 1 metabolic abnormality were 1.31 (0.79 to 2.17), 1.42 (0.83 to 2.43), and 2.39 (1.24 to 4.59), respectively. Analogous hazard ratios for patients with BMI ≥35 kg/m(2) were 1.94 (0.90 to 4.20), 1.44 (0.63 to 3.28), and 2.17 (0.91 to 5.18). All-cause mortality rates per 1,000 person-years were 55.5, 33.7, 28.3, and 33.8 in patients with BMI levels of 18.5 to 24.9, 25 to 29.9, 30 to 34.9, and ≥35 kg/m(2), respectively. In conclusion, BMI levels of 25.0 to 29.9 and 30 to 34.9 kg/m(2) were associated with lower all-cause mortality after PCI. However, an increased number of metabolic abnormalities translated into increased all-cause mortality.

Does the amount of fat mass predict age-related loss of lean mass, muscle strength, and muscle quality in older adults?

BACKGROUND

An excessive amount of adipose tissue may contribute to sarcopenia and may be one mechanism underlying accelerated loss of muscle mass and strength with aging. We therefore examined the association of baseline total body fat with changes in leg lean mass, muscle strength, and muscle quality over 7 years of follow-up and whether this link was explained by adipocytokines and insulin resistance.

METHODS

Data were from 2,307 men and women, aged 70-79 years, participating in the Health, Aging, and Body Composition study. Total fat mass was acquired from dual energy X-ray absorptiometry. Leg lean mass was assessed by dual energy X-ray absorptiometry in Years 1, 2, 3, 4, 5, 6, and 8. Knee extension strength was measured by isokinetic dynamometer in Years 1, 2, 4, 6, and 8. Muscle quality was calculated as muscle strength divided by leg lean mass.

RESULTS

Every SD greater fat mass was related to 1.3 kg more leg lean mass at baseline in men and 1.5 kg in women (p < .01). Greater fat mass was also associated with a greater decline in leg lean mass in both men and women (0.02 kg/year, p < .01), which was not explained by higher levels of adipocytokines and insulin resistance. Larger fat mass was related to significantly greater muscle strength but significantly lower muscle quality at baseline (p < .01). No significant differences in decline of muscle strength and quality were found.

CONCLUSIONS

High fatness was associated with lower muscle quality, and it predicts accelerated loss of lean mass. Prevention of greater fatness in old age may decrease the loss of lean mass and maintain muscle quality and thereby reducing disability and mobility impairments.

Sarcopenia: an undiagnosed condition in older adults. Current consensus definition: prevalence, etiology, and consequences. International working group on sarcopenia

Sarcopenia, the age-associated loss of skeletal muscle mass and function, has considerable societal consequences for the development of frailty, disability, and health care planning. A group of geriatricians and scientists from academia and industry met in Rome, Italy, on November 18, 2009, to arrive at a consensus definition of sarcopenia. The current consensus definition was approved unanimously by the meeting participants and is as follows: Sarcopenia is defined as the age-associated loss of skeletal muscle mass and function. The causes of sarcopenia are multifactorial and can include disuse, altered endocrine function, chronic diseases, inflammation, insulin resistance, and nutritional deficiencies. Although cachexia may be a component of sarcopenia, the 2 conditions are not the same. The diagnosis of sarcopenia should be considered in all older patients who present with observed declines in physical function, strength, or overall health. Sarcopenia should specifically be considered in patients who are bedridden, cannot independently rise from a chair, or who have a measured gait speed less that 1 m/s(-1). Patients who meet these criteria should further undergo body composition assessment using dual energy x-ray absorptiometry with sarcopenia being defined using currently validated definitions. A diagnosis of sarcopenia is consistent with a gait speed of less than 1 m·s(-1) and an objectively measured low muscle mass (eg, appendicular mass relative to ht(2) that is ≤ 7.23 kg/m(2) in men and ≤ 5.67 kg/m(2) in women). Sarcopenia is a highly prevalent condition in older persons that leads to disability, hospitalization, and death.

Low strength is related to diminished ground reaction forces and walking performance in older women

The purpose of this study was to determine how lower-limb strength in older women affected gait speed, supportive forces, spatial, and temporal aspects of walking gait. Twenty-four women between 65 and 80 yr performed maximal voluntary isometric contractions for the knee extensors (KE), knee flexors (KF), ankle plantarflexors (PF) and ankle dorsiflexors (DF) and were separated into low strength and normal strength groups using a KE torque threshold of 1.5 Nm kg(-1). They walked at both a standard speed of 0.8 m s(-1) and at a self-selected maximal speed on an instrumented treadmill that recorded vertical ground reaction forces (vGRF) and spatiotemporal gait measures. Older women with low strength had 30% lower KE maximal torque, 36% lower PF maximal torque, 34% lower KE rate of torque development (RTD) and 30% lower KF RTD. Low strength women demonstrated slower maximal walking speeds (1.26±0.20 m s(-1) vs. 1.56±0.20 m s(-1)), lower vGRF during weight acceptance (1.15±0.10 BW vs. 1.27±0.13 BW), lower weight acceptance rates (11.3±0.5 BW s(-1) vs. 17.0±5.5 BW s(-1)), slower stride rates, shorter stride lengths, and longer foot-ground and double-limb support times (all P<0.05). Maximal gait speed was strongly correlated to peak vGRF and rate (r=0.60-0.85, P<0.01) and moderately related to lower-limb strength (r=0.42-0.60, P<0.05). In older women with low strength, diminished peak vGRFs were associated with slower walking speeds putting them at risk for mobility limitation, disability, poor health, and loss of independence.

Poor physical function in elderly women in low-level aged care is related to muscle strength rather than to measures of sarcopenia

Purpose:

To determine the prevalence of sarcopenia and investigate relationships among body composition, muscle strength, and physical function in elderly women in low-level aged care.

Subjects and methods:

Sixty-three ambulatory women (mean age 86 years) participated in this cross-sectional study where body composition was determined by dual energy X-ray absorptiometry (DXA); ankle, knee, and hip strength by the Nicholas Manual Muscle Tester; and physical function by ‘timed up and go’ (TUG) and walking speed (WS) over 6 meters. Body composition data from a female reference group (n = 62, mean age 29 years) provided cut-off values for defining sarcopenia.

Results:

Elderly women had higher body mass index (P < 0.001), lower lean mass (P < 0.001), and higher fat mass (P < 0.01) than the young reference group. Only a small proportion (3.2%) had absolute sarcopenia (defined by appendicular skeletal muscle mass/height squared) whereas 37% had relative sarcopenia class II (defined by percentage skeletal muscle mass). Scores for TUG and WS indicated relatively poor physical function, yet these measures were not associated with muscle mass or indices of sarcopenia. In multivariate analysis, only hip abductor strength predicted both TUG and WS (both P = 0.01).

Conclusion:

Hip strength is a more important indicator of physical functioning than lean mass. Measurement of hip strength may therefore be a useful screening tool to detect those at risk of functional decline and requirement for additional care. Further longitudinal studies with a range of other strength measures are warranted.

Ageing, but not yet senescent, rats exhibit reduced muscle quality and sarcoplasmic reticulum function

AIM

Reduced muscle force greater than expected from loss of muscle mass has been reported in ageing muscles. Impaired sarcoplasmic reticulum (SR) Ca(2+) release has been implicated as a possible mechanism, and attributed to several factors, including loss of ryanodine receptor (RYR) expression and protein binding. The aim of this study was to evaluate muscle quality and SR Ca(2+) release in ageing rats that were not so old that major atrophy had occurred.

METHODS

We collected in situ force data from the plantarflexor muscle group and muscle mass from the constituent muscles to determine muscle quality (force/mass) in adult (6-8 months) and ageing (24 months) rats (n=8/group). We evaluated SR Ca(2+) uptake and release, and determined expression of key proteins associated with Ca(2+) release [RYR and FK506 binding protein (FKBP)] and uptake (SERCA, parvalbumin, calsequestrin).

RESULTS

Plantarflexor force and muscle quality were reduced with ageing (approx. 28 and 34%, respectively), but atrophy was limited, and significant only in the medial gastrocnemius (approx. 15%). The fast phase of SR Ca(2+) release was reduced with ageing in both gastrocnemii, as was FKBP expression and FKBP-RYR binding, but RYR expression was not affected. Similar, but non-significant changes were present in the plantaris, but the soleus muscle generally showed no ageing-related changes.

CONCLUSION

These data suggest a possible role for impaired SR Ca(2+) release in ageing-related loss of muscle quality, although not through loss of RYR expression.

Reliability and clinical correlates of 3D-accelerometry based gait analysis outcomes according to age and fall-risk

PURPOSE

To investigate the reliability of a 3D-accelerometry based gait analysis, and its correlates with clinical status and fall-risk.

METHODS

Forty elderly subjects presenting with increased fall-risk (OFR), 41 elderly controls (OC) and 40 young controls (aged 80.6±5.4, 79.1±4.9 and 21.6±1.4 years respectively) underwent three gait evaluations (two assessors in random order) each containing two walks of 18 m with a DynaPort MiniMod accelerometer on the pelvis. Intra- and inter-observer reliability of gait speed, step-time asymmetry, mediolateral and craniocaudal step and stride regularity were determined by ICC and CV of standard error of measurement (CV(SEM)). Relationships with cognition (MMSE), dependency, grip strength, muscle endurance, and fall-risk (fall-history, timed-get-up-and-go and Tinetti-test) were analysed in elderly participants.

RESULTS

Reliability for single walk was low (ICC<0.70, 11%<CV(SEM)<23%), except for mediolateral step regularity (0.70≤ICC<0.80) and gait speed (ICC>0.80, CV(SEM)<7%), but high (ICC>0.70, 4%<CV(SEM)<20%) when based on the mean of two walks; except for step-time asymmetry (42%<CV(SEM)<77%). Compared to OC, OFR showed significantly (p<0.05) slower gait speed, and worse step and stride regularity. Gait speed, step-time asymmetry, step and stride regularity related significantly (p<0.05) with several functional outcomes. Besides gait speed (1.158 m/s, 78% sensitivity and 78% specificity), none of the gait features showed sufficient discriminative capacity according to fall-risk.

CONCLUSIONS

In all participants together, 3D-accelerometry based gait speed and regularity showed high reliability when based on two walks of 18 m. Relationships with functional characteristics support the validity of gait variability features in elderly persons. More fundamental and prospective research is necessary to clarify their clinical value.

Association between obesity history and hand grip strength in older adults--exploring the roles of inflammation and insulin resistance as mediating factors

BACKGROUND

To examine the association between obesity history and hand grip strength, and whether the association is partly explained by subclinical inflammation and insulin resistance.

METHODS

Data are from 2,021 men and women aged 55 years and older participating in the representative population-based Health 2000 Survey in Finland. Body mass and body height, maximal hand grip strength, C-reactive protein, and insulin resistance based on homeostasis model assessment (HOMA-IR) were measured in a health examination. Recalled weight at 20, 30, 40, and 50 years of age were recorded to obtain a hierarchical classification of obesity history. Obesity was defined as body mass index ≥ 30 kg/m².

RESULTS

Earlier onset of obesity was associated with lower hand grip strength (p < .001) after controlling for age, sex, education, smoking, alcohol use, physical activity, several chronic diseases, and current body weight. Based on adjusted logistic regression models, the odds (95% confidence interval) for very low relative hand grip strength were 2.76 (1.78-4.28) for currently obese, 5.57 (3.02-10.28) for obese since age of 50 years, 6.53 (2.98-14.30) for obese since age of 40 years, and 10.36 (3.55-30.24) for obese since age of 30 years compared with never obese participants. The associations remained highly significant even after adjusting for current C-reactive protein and HOMA-IR, but these variables had only minor role in explaining the association between obesity history and hand grip strength.

CONCLUSIONS

Long-term exposure to obesity is associated with poor hand grip strength later in life. Maintaining healthy body weight throughout the life span may help to maintain adequate muscle strength in old age. Prospective studies with information on prior muscle strength are needed to examine in detail the causal association between obesity history and muscle strength.