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- 1. 4th International Seminar on Preventive Geriatrics & 1st International Seminar on Geriatric Rehabilitation Yves ROLLAND Inserm U1027, University of Toulouse, Gerontopôle, FRANCE Evaluation of sarcopenia
- 2. A - Why a consensual definition of sarcopenia ? B - The different clinical approaches C – European Working Group on Sarcopenia Agenda
- 3. A - Why a consensual definition of sarcopenia ? B - The different clinical approaches C – European Working Group on Sarcopenia Agenda
- 4. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? Irwin Rosenberg (1989) Sarcopenia : the observed age-related decline in muscle mass Age-related loss of muscle mass Age-related loss of muscle strength Low muscle mass in old age Loss of muscle mass Loss of muscle strength Low muscle strength in old age Low muscle mass, muscle strength and function in old age Since 1989
- 5. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? What is the prevalence among countries or ethnicities ? Prevalence ? Target population ? Generalization of the results ? American Cohorts European and Asiatic Cohorts % %
- 6. Cachexia, sarcopenia, starvation, frailty - overlapping conditions 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? Sarcopenia, an overlapping condition ? Cachexia Starvation Sarcopenia Frailty An unclear distinction !
- 7. 4th International Seminar on Preventive Geriatrics Janssen I et al. J Am Geriatr Soc 2002; 50: 889 - 89 A - Why a consensual definition of sarcopenia ? Sarcopenia, an overlapping condition ? No data reported on Cachexia (Disease…) Starvation (nutritional intake..) Frailty (physical inactivity..) Prevalence of SARCOPENIA based only on muscle mass NHANES III
- 8. Medline Pubmed 2010 : 773 publications with “sarcopenia” 28 publications with “sarcopenia” + “RCT” 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? DRUGS FOR IMPROVING FUNCTIONAL STATUS IN OLDER PERSONS
- 9. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? DRUGS FOR IMPROVING FUNCTIONAL STATUS IN OLDER PERSONS Yearly costs, (US) Osteoporotic fractures $16.3 billion $18.5 billion Sarcopenia
- 10. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? DRUGS FOR IMPROVING FUNCTIONAL STATUS IN OLDER PERSONS Map of 721 studies found by search of: osteoporosis JUNE 2010
- 11. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? DRUGS FOR IMPROVING FUNCTIONAL STATUS IN OLDER PERSONS Map of 38 studies found by search of: sarcopenia Only a handful of clinical trials are under way to treat sarcopenia JUNE 2010
- 12. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? DRUGS FOR IMPROVING FUNCTIONAL STATUS IN OLDER PERSONS The FDA may not consider sarcopenia itself as an indication for treatment. How treatments of mobility limitation should be Developed ? Tested ?
- 13. 4th International Seminar on Preventive Geriatrics A - Why a consensual definition of sarcopenia ? An operational definition of sarcopenia that can be used both for research and clinical practice is needed
- 14. A - Why a consensual definition of sarcopenia ? B - The different clinical approaches C – Sarcopenia working group (European Union Geriatric Medicine Society) Agenda
- 15. ANTHROPOMETRY Low cost, easy, low accuracy BIOLOGY (creatinine excretion , 40 K) Complicated BIA (bio-impedancemetry) Low cost, easy, low accuracy IMAGING MRI and CT Muscle quality, high cost, difficult to perform, radiations DXA Low cost, accurate, easy, No information about muscle quality 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Assessment of muscle mass
- 16. ANTHROPOMETRY Low cost, easy, low accuracy BIOLOGY (creatinine excretion , 40 K) Complicated BIA (bio-impedancemetry) Low cost, easy, low accuracy IMAGING MRI and CT Muscle quality, high cost, difficult to perform, radiations DXA Low cost, accurate, easy, No information about muscle quality 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Assessment of muscle mass
- 17. B - The different clinical approaches Dual X-ray Absorptiometry (DXA) Baumgartner et al. (1998) skeletal muscle mass index (SMI) = ASM/height² in kg/m² SMI less than 2 SD below the mean SMI of a reference young population from the Rosetta study are considered sarcopenic. Men < 7.26 kg/m ² Women < 5.45 kg/m ² 4th International Seminar on Preventive Geriatrics
- 18. Osteoporosis 4th International Seminar on Preventive Geriatrics Sarcopenia ? Age (years) Age (years) B - The different clinical approaches Dual X-ray Absorptiometry (DXA) Baumgartner et al. (1998) Fracture threshold Men Woman Mobility limitation threshold Men Woman Muscle mass Bone Mineral Density
- 19. 4th International Seminar on Preventive Geriatrics Associations of sarcopenia with physical disability or a history of injury New Mexico Elder Health Survey, 1993-1995 t OR for >3 disabilities were adjusted for age, ethnicity, obesity , income, alcohol intake, physical activity score, current smoking, and comorbidity. OR for all other variables were adjusted for age, ethnicity, obesity , comorbidity, and alcohol intake. B - The different clinical approaches Dual X-ray Absorptiometry (DXA) Baumgartner et al. (1998)
- 20. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches ASM/height² Advantages - Easy to apply - Understandable Disadvantages - Need a DXA - The threshold - Obese and thin - Muscle mass : the most important clinical parameter
- 21. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Need a DXA Already used in the diagnosis of osteoporosis but Low access to the DXA, specially for frail elderly
- 22. Osteoporosis ≠ Sarcopenia 4th International Seminar on Preventive Geriatrics B - The different clinical approaches What threshold ? Reference population ? How to define mobillity limitation ? Mobility limitation threshold Men Woman Muscle mass
- 23. Dual X-ray Absorptiometry (DXA) Janssen, Baumgartner, Ross, Rosenberg, Roubenoff (2004) 4,449 participants from the Third NHANES 1988–1994 4th International Seminar on Preventive Geriatrics Moderate risk SMI 5.76-6.75 women SMI 8.51-10.75 men
- 24. Dual X-ray Absorptiometry (DXA) Janssen, Baumgartner, Ross, Rosenberg, Roubenoff (2004) 4,449 participants from the Third NHANES 1988–1994 4th International Seminar on Preventive Geriatrics High risk SMI ≤5.75 women SMI ≤8.50 men
- 25. Dual X-ray Absorptiometry (DXA) Janssen, Baumgartner, Ross, Rosenberg, Roubenoff (2004) 4,449 participants from the Third NHANES 1988–1994 4th International Seminar on Preventive Geriatrics ASM/height²
- 26. High muscle mass with mobility limitations Low Muscle mass without mobility limitations Thin Obese 4th International Seminar on Preventive Geriatrics B - The different clinical approaches (DXA) ASM/height²
- 27. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Sarcopenic Obese Dual X-ray Absorptiometry (DXA) NS, NO: nonsarcopenic, nonobese S, NO: sarcopenic, nonobese NS, O: nonsarcopenic, obese S, O: sarcopenic, obese Survival curve for time to drop in IADL by body composition type Sarcopenic Obese
- 28. 6414 persons (NHANES III) 4th International Seminar on Preventive Geriatrics B - The different clinical approaches ASM/weight x100 Sarcopenia : 1 SD below the mean = class I 2 SD below the mean = class II Men class 1 = 31.5 – 37% class 2 = <31.5% Women class 1 = 22.1 – 27.6% class 2 = <22.1
- 29. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Residual method Height (m) Appendicular Muscle Mass (kg) men r=0.49 Residual method
- 30. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Residual method Lean Mass is derived by adjusting for fat mass in addition to height Newman et al.
- 31. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches ASM/height² ASM/weight Residual method Advantages - More or less easy to apply in clinical practice - Understandable Disadvantages - Need a DXA - The threshold - Obese and thin - Muscle mass : the most important clinical parameter
- 32. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Muscle mass : the most important clinical parameter ? A strong interrelationship between lower extremity muscle mass and muscle strength muscle mass accounted for 60% of the total variance in muscle strength Lower extremity muscle mass and muscle strength are independent determinants of the severity of mobility-disability.
- 33. Potential sites and physiological mechanisms that regulate strength J Geront Med Sci 2008: 829-834 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Muscle mass : the most important clinical parameter ? Decreased cortical excitability Decreased spinal excitability Decreased maximal motor unit discharge rate slowed nerve conduction 5 Alterations in muscle architecture 6 & 7 Decreased muscle mass; Increased myocellular lipid content E-C uncoupling
- 34. Physical performance or muscle strength tests 4th International Seminar on Preventive Geriatrics B - The different clinical approaches
- 36. 4th International Seminar on Preventive Geriatrics Muscle Quality How different measures of muscle mass/function identify participants with mobility problems. Several putative indicators of sarcopenia Lauretani et al. J Appl Physiol 2003
- 37. 4th International Seminar on Preventive Geriatrics B - The different clinical approaches Grip strength, knee ext strength, muscle power… Advantages - More or less easy to apply in clinical practice - Understandable - Simple (hand grip strength, …) or no device Disadvantages - Which functional test ? - The threshold - Depend on motivation, willpower, pain (osteoarthritis) - Muscle strength : the most important parameter
- 38. A - Why a consensual definition of sarcopenia ? B - The different clinical approaches C – Sarcopenia working group (European Union Geriatric Medicine Society) Agenda
- 39. Definition & Diagnosis of Sarcopenia Endorsed by European Society for Clinical Nutrition & Metabolism International Association of Gerontology & Geriatrics International Academy of Nutrition & Aging European Union Geriatric Medicine Society 4th International Seminar on Preventive Geriatrics C - SARCOPENIA WORKING GROUP
- 40. C - EWGSOP Working Definition of Sarcopenia
- 41. C - EWGSOP Working Definition of Sarcopenia Cruz-Jentoft AJ et al. Sarcopenia: European consensus on definition and diagnosis. Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010 Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life and death. CRITERIA FOR THE DIAGNOSIS OF SARCOPENIA LOW MUSCLE MASS LOW PHYSICAL PERFORMANCE LOW MUSCLE STRENGTH OR SARCOPENIA
- 42. C - EWGSOP Working Definition of Sarcopenia Cruz-Jentoft AJ et al. Sarcopenia: European consensus on definition and diagnosis. Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010 Sarcopenia staging, which reflects the severity of the condition, is a concept that can help guide clinical management of the condition. Stage Muscle mass Muscle strength Performance Presarcopenia ↓ Sarcopenia ↓ ↓ Or ↓ Severe sarcopenia ↓ ↓ ↓
- 43. C - EWGSOP Working Definition of Sarcopenia Cruz-Jentoft AJ et al. Sarcopenia: European consensus on definition and diagnosis. Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010 LOW MUSCLE MASS LOW PHYSICAL PERFORMANCE LOW MUSCLE STRENGTH OR SARCOPENIA SEVERE SARCOPENIA PRE-SARCOPENIA AND Sarcopenia staging, which reflects the severity of the condition, is a concept that can help guide clinical management of the condition.
- 44. C - EWGSOP Working Definition of Sarcopenia Cruz-Jentoft AJ et al. Sarcopenia: European consensus on definition and diagnosis. Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010 EWGSOP Categories of sarcopenia Primary Age-related Secondary
- 45. C - EWGSOP Working Definition of Sarcopenia Cruz-Jentoft AJ et al. Sarcopenia: European consensus on definition and diagnosis. Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010 Suggested measures to diagnose sarcopenia
- 46. C - EWGSOP Working Definition of Sarcopenia Cruz-Jentoft AJ et al. Sarcopenia: European consensus on definition and diagnosis. Report of the European Working Group on Sarcopenia in Older People. Age Ageing 2010 Case finding Subject >65 years Usual gait speed No sarcopenia Muscle mass Grip stregth No sarcopenia Sarcopenia NORMAL NORMAL SLOW LOW LOW NORMAL LOW MUSCLE STRENGTH
Editor's Notes
- Lady and gentleman, Sarcopenia is currently considered to be one of the hallmarks of the aging process. It however suprising that in 2011, they is still no consensual definition of sarcopenia.
- Lady and gentleman, thank you to invite me. Sarcopenia is actually considered to be one of the hallmarks of the aging process. It howerver suprising that in 2009, they is still no consensual definition of sarcopenia. I will give the summary of on-going reflexion on sarcopenia of a groupe conducted by the EUGMS working on a definition of sarcopenia
- Lady and gentleman, thank you to invite me. Sarcopenia is actually considered to be one of the hallmarks of the aging process. It howerver suprising that in 2009, they is still no consensual definition of sarcopenia.
- Rosenberg was the first in 1989 to used the term sarcopenia. His aim was to hightlight the important of muscle muscle in the disability process. Since 1989 and the first sarcopenia workshop held by the National Institute of Aging in 1994, the definition of sarcopenia has continue to evolved. Actually, definition of sarcopenia considers loss of muscle function (muscle strength) and loss of quality (muscle strength / muscle mass) in addition to the loss of muscle protein mass. However, despite intense clinical research, a worldwide operation definition of sarcopenia is still lacking. Moreover, whether the motor functional capacity loss in elderly people (ability to rise from a chair, to prevent falls, to walk in the street, to carry a bag…) is mainly due to the loss of muscle mass or the qualitative impairment of the muscle tissue remains poorly known [3]. Irwin Rosenberg defined sarcopenia in 1989 to describe a recognized age-related decline in muscle mass among the elderly. Since 1989, various definitions of sarcopenia have evolved as our understanding of the aging process. Sarcopenia is actually considered to be one of the hallmarks of the aging process. It howerver suprising that in 2009, they is still no consensual definition of sarcopenia.
- As there is no clear definition of sarcopenia, Different prevalence among countries or ethnicities? Generalization of the results ? Target population (inclusion-exclusion) ? Outcomes ?
- Another difficulty is that many condition such as Satrva…. Lead to a loss of muscle Mass. And there still an unclear distinction between expert. It is very diffucult to distinghuish all these condition wich are frequently asscciated. It is difficult to know of what we are speaking We need to be clear, because these condition NEED different therapeutic approach.
- It would be stress that in most ^pidemiological study
- It is also important to have a clear def of sarcopenia because there is a growing interess in sarcopenia and the
- To put this in perspective, it has been estimated that the yearly economic costs of osteoporotic fractures in the United States is $16.3 billion (adjusted to 2000 dollars)
- On-going and future clinical trials on sarcopenia may radically change our preventive and therapeutic approaches of mobility disability in older people.
- An another big issu is how sarcopenia can become an indication in regard to the conditions FDA or other similar organisations. Because sarcopenia is a geriatric syndrome. Although our society urgently needs new treatments that can reduce the burden of physical decline among older persons, Guidelines on how treatments of mobility limitation should be developed and tested are currently lacking in part because a consensus has not yet been achieved regarding the identifiable target diseases. The etiology of these functional limitations is complex and often ascribed to conditions that escape the traditional definition of Disease The FDA may not consider sarcopenia itself as an indication at this time. First, its direct association with functional status and quality-of-life outcomes is complex and still being researched. Second, no professional organization has issued a position statement concerning sarcopenia as a treatable condition.
- In 1992, Chapuy and Meunier were probably the first to demonstrate that Vitamin D in Nursing reduce the risk of Hip fracture. At that period, the authors did not imagine that the reduction of therisk was not only related to the increase BMD but also to the reduction of the risk of fall. At that period they did not know the close relationship between vitamin D and Fall and sarcopenia.
- Lady and gentleman, thank you to invite me. Sarcopenia is actually considered to be one of the hallmarks of the aging process. It howerver suprising that in 2009, they is still no consensual definition of sarcopenia.
- ANTHROPOMETRY (calf, formula) Low cost, easy, low accuracy BIOLOGY (creatinine excretion, 40K) Complicated BIA Low cost, easy, low accuracy IMAGING MRI and CT Muscle quality, high cost, difficult to perform , radiations DXA (Appendicular skeletal muscle mass (kg)) Low cost, accurate, easy , No information about muscle quality
- ANTHROPOMETRY (calf, formula) Low cost, easy, low accuracy BIOLOGY (creatinine excretion, 40K) Complicated BIA Low cost, easy, low accuracy IMAGING MRI and CT Muscle quality, high cost, difficult to perform , radiations DXA (Appendicular skeletal muscle mass (kg)) Low cost, accurate, easy , No information about muscle quality
- The first approach to define sarcopenia amongst elderly subject was developed in. from the New Mexico Elders Aging Study [16] database. Their approach relies on the notion of appendicular muscular mass previously reported by Heymsfield [17]: Dual-energy X-ray Absorptiometry (DXA) allows a valid quantitative assessment of the skeletal muscle mass [18, 19]. Then, the muscular mass of the four limbs, or appendicular skeletal muscle mass (ASM) can be obtained. Sarcopenia is then defined with ASM/height² or skeletal muscle mass index (SMI) in weight per meter² (kg/m²) because a value relating to the patient measurements is necessary to study the ASM. Subjects with a SMI less than two standard deviations below the mean SMI of a reference young population from the Rosetta study [9] are then considered sarcopenic. This quantitative approach, similar to the World Health Organization (WHO) approach used to define osteoporosis, have been used by several authors using appendicular muscle mass [11, 13, 16].
- Ths strategy is analogous to that used to defined OSTEOPOROSIS which is based on T-Score values below a certain cut-off.
- In 1992, Chapuy and Meunier were probably the first to demonstrate that Vitamin D in Nursing reduce the risk of Hip fracture. At that period, the authors did not imagine that the reduction of therisk was not only related to the increase BMD but also to the reduction of the risk of fall. At that period they did not know the close relationship between vitamin D and Fall and sarcopenia.
- Advantages of this approach: - Easy to apply - understandable by most physicians Disadvantages This appoach assume that muscle mass is the most important clinical parameter to be assessed. A large body of data demonstrate that the strength generate by a unit of muscle mass is very variable between genders and tend s to decline steadily with aging. The threshold in Bone mineral density used for the for the definition of osteoporosis was selected based on observed risk of hip fracture in longitudinal studies.
- Advantages of this approach: - Easy to apply - understandable by most physicians Disadvantages This appoach assume that muscle mass is the most important clinical parameter to be assessed. A large body of data demonstrate that the strength generate by a unit of muscle mass is very variable between genders and tend s to decline steadily with aging. The threshold in Bone mineral density used for the for the definition of osteoporosis was selected based on observed risk of hip fracture in longitudinal studies.
- The threshold in Bone mineral density used for the definition of osteoporosis was selected based on observed risk of hip fracture in longitudinal studies.
- Another limitation is represented by this “U “ shape association between … The increased physical disability risk in women with very high SMI values may have in part reflected the increased fat mass and obesity in these subjects. Fat mass is an independent predictor of physical disability (21, 22), and fat mass was considerably higher (39.2 kg vs. 28.1 kg) in women with very high SMI values (≥9.00 kg/m2) than in women with moderately high SMI values (6.75–8.99 kg/m2).
- The increased physical disability risk in women with very high SMI values may have in part reflected the increased fat mass and obesity in these subjects. Fat mass is an independent predictor of physical disability (21, 22), and fat mass was considerably higher (39.2 kg vs. 28.1 kg) in women with very high SMI values (≥9.00 kg/m2) than in women with moderately high SMI values (6.75–8.99 kg/m2).
- The increased physical disability risk in women with very high SMI values may have in part reflected the increased fat mass and obesity in these subjects. Fat mass is an independent predictor of physical disability (21, 22), and fat mass was considerably higher (39.2 kg vs. 28.1 kg) in women with very high SMI values (≥9.00 kg/m2) than in women with moderately high SMI values (6.75–8.99 kg/m2).
- Compared to the non-obese, obese usually have higher muscle mass but lower muscle mass in relation to their high body weight [20]. On the other hand, thin elderly are classified sarcopenic despite a high muscle mass in relation to their low body weight. Then, the SMI misclassifies obese with a high SMI but mobility limitations and thin elderly with a low SMI but without mobility limitations.
- Because most mobility task are influence by body size, it seem more appropriate to express muscle mass in relation to body size OBJECTIVES: To establish the prevalence of sarcopenia in older Americans and to test the hypothesis that sarcopenia is related to functional impairment and physical disability in older persons. DESIGN: Cross-sectional survey. SETTING: Nationally representative cross-sectional survey using data from the Third National Health and Nutrition Examination Survey (NHANES III). PARTICIPANTS: Fourteen thousand eight hundred eighteen adult NHANES III participants aged 18 and older. MEASUREMENTS: The presence of sarcopenia and the relationship between sarcopenia and functional impairment and disability were examined in 4,504 adults aged 60 and older. Skeletal muscle mass was estimated from bioimpedance analysis measurements and expressed as skeletal muscle mass index (SMI = skeletal muscle mass/body mass x 100). Subjects were considered to have a normal SMI if their SMI was greater than -one standard deviation above the sex-specific mean for young adults (aged 18-39). Class I sarcopenia was considered present in subjects whose SMI was within -one to -two standard deviations of young adult values, and class II sarcopenia was present in subjects whose SMI was below -two standard deviations of young adult values. RESULTS: The prevalence of class I and class II sarcopenia increased from the third to sixth decades but remained relatively constant thereafter. The prevalence of class I (59% vs 45%) and class II (10% vs 7%) sarcopenia was greater in the older (> or = 60 years) women than in the older men (P <.001). The likelihood of functional impairment and disability was approximately two times greater in the older men and three times greater in the older women with class II sarcopenia than in the older men and women with a normal SMI, respectively. Some of the associations between class II sarcopenia and functional impairment remained significant after adjustment for age, race, body mass index, health behaviors, and comorbidity. CONCLUSIONS: Reduced relative skeletal muscle mass in older Americans is a common occurrence that is significantly and independently associated with functional impairment and disability, particularly in older women. These observations provide strong support for the prevailing view that sarcopenia may be an important and potentially reversible cause of morbidity and mortality in older persons.
- Relative LM was first calculated using the index (aLM/ ht2) proposed by Baumgartner,5,9 but instead of comparing index values with a cutoff from a younger population, participants were classified as sarcopenic if their value fell into the sex-specific lowest 20% of the distribution of the index in order to compare this method with the alternative below. Of note, these cutpoints of 7.23 kg/ht2 (men) and 5.67 kg/ht2 (women) were similar to values previously reported of 7.26 kg/ht2 (men) and 5.45 kg/ht2 (women).5,9 A second measure of relative LM was derived by adjusting for fat mass in addition to height. Linear regression was used to model the relationship between aLM on height (meters) and fat mass (kg). The residuals of the regression were used to identify those whose LM was much lower or higher than the predicted value. A positive residual would indicate a relatively muscular individual, whereas negative values would indicate relatively sarcopenic individuals. The 20th percentile of the distribution of residuals was used as the cutpoint for sarcopenia. Separate models were fit for men (aLM (kg)5–22.481 24.14height (m)10.21total fat mass (kg)) and women (aLM (kg)5–13.19114.75height (m)10.23 total fat mass (kg)). A tabulation of LM by height and fat mass in the Health ABC cohort based on these equations is available from the first author.
- When you use this approach you reduce the overestimation of sarcopenia in the thin and also improve the underestimation in the obese. Relative LM was first calculated using the index (aLM/ ht2) proposed by Baumgartner,5,9 but instead of comparing index values with a cutoff from a younger population, participants were classified as sarcopenic if their value fell into the sex-specific lowest 20% of the distribution of the index in order to compare this method with the alternative below. Of note, these cutpoints of 7.23 kg/ht2 (men) and 5.67 kg/ht2 (women) were similar to values previously reported of 7.26 kg/ht2 (men) and 5.45 kg/ht2 (women).5,9 A second measure of relative LM was derived by adjusting for fat mass in addition to height. Linear regression was used to model the relationship between aLM on height (meters) and fat mass (kg). The residuals of the regression were used to identify those whose LM was much lower or higher than the predicted value. A positive residual would indicate a relatively muscular individual, whereas negative values would indicate relatively sarcopenic individuals. The 20th percentile of the distribution of residuals was used as the cutpoint for sarcopenia. Separate models were fit for men (aLM (kg)5–22.481 24.14height (m)10.21total fat mass (kg)) and women (aLM (kg)5–13.19114.75height (m)10.23 total fat mass (kg)). A tabulation of LM by height and fat mass in the Health ABC cohort based on these equations is available from the first author.
- Advantages of this approach: - Easy to apply - understandable by most physicians Disadvantages This appoach assume that muscle mass is the most important clinical parameter to be assessed. A large body of data demonstrate that the strength generate by a unit of muscle mass is very variable between genders and tend s to decline steadily with aging. The threshold in Bone mineral density used for the for the definition of osteoporosis was selected based on observed risk of hip fracture in longitudinal studies.
- Although muscle mass is related to strength, it is by no means the only determinant of force production. Objectives— This study examined the influence of lower extremity body composition and muscle strength on the severity of mobility-disability in community-dwelling older adults. Methods— Fifty-seven older males and females (age 74.2 ± 7 yrs; BMI 28.9 ± 6 kg/m2) underwent an objective assessment of lower extremity functional performance, the Short Physical Performance Battery test (SPPB). Participants were subsequently classified as having moderate (SPPB score > 7: n = 38) or severe mobility impairments (SPPB score ≤7: n = 19). Body composition was assessed using dual-energy X-ray absorptiometry and provided measures of bone mineral density (BMD), total leg lean mass (TLM) and total body fat. Maximal hip extensor muscle strength was estimated using the bilateral leg press exercise. Multiple logistic regression analysis was utilized to identify the significant independent variables that predicted the level of mobility-disability. Results— TLM was a strong independent predictor of the level of functional impairment, after accounting for chronic medical conditions, BMD, body fat, body weight and habitual physical activity. In a separate predictive model, reduced muscle strength was also a significant predictor of severe functional impairment. The severity of mobility-disability was not influenced by gender (p = 0.71). A strong association was elicited between TLM and muscle strength (r = 0.78, p < 0.01). Conclusions— These data suggest that lower extremity muscle mass is an important determinant of physical performance among functionally-limited elders. Such findings may have important implications for the design of suitable strategies to maintain independence in older adults with compromised physical functioning. Additional studies are warranted to assess the efficacy of lifestyle, exercise or therapeutic interventions for increasing lean body mass in this population. This investigation has demonstrated that lower extremity muscle mass and muscle strength are independent determinants of the severity of mobility-disability in older adults with compromised physical functioning. These findings are important as they suggest that, within this specific population, these two modifiable physiological parameters have stronger predictive capability compared to several other previously reported anthropometric and lifestyle correlates of functional decline. Our findings also confirm a strong interrelationship between lower extremity muscle mass and muscle strength, and extend this association among a group of mobility-impaired elders who exhibited performance-based limitations in physical functioning. The loss of muscle mass with advancing age, or sarcopenia, is hypothesized as being closely associated with the deterioration of physical function (26). From the published literature, this relationship has not been firmly established, as studies describing the relation between low muscle mass and physical function have provided inconsistent results (12,13,15,27,28). There may, however, be several plausible explanations for this discordance. Many of the previous large-scale observational studies have attempted to characterize this relationship in healthy, well-functioning older adults with relatively narrow age ranges (27). This may have resulted in an underestimation of any observed associations, as mobility-impaired elders are more likely to have lower muscle mass and reduced muscle strength when compared to elders of high functional status (6,14,26). Furthermore, many of the previous studies have also used selfreport methods to assess functional status. Incident mobility limitations based on subjective self-report measures have been shown to be influenced by factors such as cognitive status, perceived mastery, and depressive symptoms, which may lead to a potential misclassification bias in these studies (15). In addition, there is also the strong likelihood that the sarcopeniafunctional decline relationship is influenced by other inevitable and concurrent age-related Reid et al. Page 5 J Nutr Health Aging . Author manuscript; available in PMC 2008 September 19. NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript changes in body composition and muscle quality, which may include an increase in fat tissue, a loss of bone mass, and alterations in neural activation (26). The current study confirms that the age-related loss of lean muscle mass and strength are important determinants of mobility-disability in old age. We sought to overcome many of the limitations in previous studies by incorporating a robust, objective and well-validated method to ascertain functional status. After controlling for several other physiological and lifestyle factors associated with decreased function, logistic regression analyses revealed that for every kilogram increase in total lean leg mass, the odds of having severe functional limitations decreased by 53% (Table 4). The relation between muscle mass and mobility-disability was also supported by the generalized additive model analysis, which showed graphically that a SPPB score > 7 was associated with a marked increase in lean leg muscle mass. Given this relationship, together with the finding that muscle mass accounted for over 60% of the total variance in muscle strength in this population of frail elders, it was not surprising that muscle strength was also a significant independent predictor of the severity of mobility-disability in a separate regression model. It is also highly likely that additional indices of muscle quality such as neuromuscular function and skeletal muscle fat infiltration would explain a portion of the total variance in muscle strength and contribute to the severity of mobility-disability in these participants (29). Unfortunately, these additional factors were not assessed in the current study. The findings described in this study support the view that intervention strategies designed to preserve both skeletal muscle mass and muscle strength should be initiated among older adults. Resistance exercise may be particularly beneficial because it has been shown to attenuate or reverse the age-related decrements in muscle mass and strength (30–33). However, other factors have also been reported to contribute to the age-associated decline in skeletal muscle mass. These include declining levels of steroid hormones, reduced dietary protein intake, and decreased levels of physical activity (14). Additional studies are still necessary in order to develop optimal interventions designed to maintain muscle mass, strength and function among older adults. Despite the robust association between muscle mass and function, there are limitations associated with this study. The cross-sectional nature of the analysis precludes definitive causal inferences about the relationship between muscle mass, strength and the level of mobilitydisability. It is also possible that the decline in functional performance may have preceded the reductions in both muscle mass and strength in this population. Although DXA assessment of muscle mass is reproducible and has been validated against other body composition assessment methodologies, it does not capture important intrinsic changes in muscle quality (e.g. intermuscular fat infiltration) that accompany aging (34). Conclusions The findings of this study suggest that preservation of skeletal muscle mass may be an important intervention in the disablement pathway among mobility-impaired older adults. Such findings may have important implications for the design of suitable strategies to maintain functional independence, and indicate that efforts to preserve and increase muscle mass are likely to have a significant effect on preserving strength and function in this population. Additional studies are warranted to assess the efficacy of exercise, lifestyle or pharmacologic interventions for increasing muscle mass in functionally-limited elders. Further prospective research is also needed to delineate the relative contributions of muscle mass and muscle strength, together with the role of other neuromuscular, anthropometric, and lifestyle factors that potentially contribute to the onset and progression of mobility-disability with advancing age.
- Potential sites and physiological mechanisms that regulate strength. The neuromuscular system contains several potential sites that can affect voluntary force or power production, such as excitatory drive from supraspinal centers, a-motoneuron excitability, antagonistic muscle activity, motor unit recruitment and rate coding, neuromuscular transmission, muscle mass, excitation-contraction (E-C) coupling processes, and muscle morphology and architecture. There is evidence of aging-induced alterations at nearly every denoted site within the system such as, but not limited to, the following: (1) decreased cortical excitability (36); (2) decreased spinal excitability (29); (3) decreased maximal motor unit discharge rate (28); (4) slowed nerve conduction (37); (5) alterations in muscle architecture (reduced fascicle length and pennation angle, and tendon stiffness) (33); (6) decreased muscle mass (sarcopenia) (12); (7) increased myocellular lipid content (38); (8) E-C uncoupling (i.e., decreased number of dihydropyridine receptors) (35). Please see Figure 3 for a more detailed processes related to dynapenia.
- The same amount of muscle mass can generate different level of strength. So, muscle strength alone is probably not the best way of define sarcopenia. The main effect of loss of muscle mass is the reduced muscle strength. Then, another option to define sarcopenia is to assess muscle strength, such as grip strength which can provide an estimation of global muscle strength [34] or lower extremity physical performances accessed for instance on leg press. This approach seems logical as several authors have reported that muscle strength more than muscle mass was independently associated with physical performances [35]. However, different factors may underlie and contribute in varying degree to the loss of muscle strength and loss of muscle mass. Moreover, loss of muscle quality, an important component of the definition of sarcopenia, supposed an assessment of both muscle strength and muscle mass.
- The same amount of muscle mass can generate different level of strength. So, muscle strength alone is probably not the best way of define sarcopenia. The main effect of loss of muscle mass is the reduced muscle strength. Then, another option to define sarcopenia is to assess muscle strength, such as grip strength which can provide an estimation of global muscle strength [34] or lower extremity physical performances accessed for instance on leg press. This approach seems logical as several authors have reported that muscle strength more than muscle mass was independently associated with physical performances [35]. However, different factors may underlie and contribute in varying degree to the loss of muscle strength and loss of muscle mass. Moreover, loss of muscle quality, an important component of the definition of sarcopenia, supposed an assessment of both muscle strength and muscle mass.
- InCHIANTI The prevalence of sarcopenia was maximum for muscle power. However, lower extremity muscle power was no better than knee extension torque or handgrip in the early identification of poor mobility. in skeletal muscles and their effect on mobility: an operational diagnosis of sarcopenia. J Appl Physiol 95: 1851–1860, 2003; 10.1152/japplphysiol.00246.2003.—Sarcopenia, the reduction of muscle mass and strength that occurs with aging, is widely considered one of the major causes of disability in older persons. Surprisingly, criteria that may help a clinician to identify persons with impaired muscle function are still lacking. Using data from a large representative sample of the general population, we examined how muscle function and calf muscle area change with aging and affect mobility in men and women free of neurological conditions. We tested several putative indicators of sarcopenia, including knee extension isometric torque, handgrip, lower extremity muscle power, and calf muscle area. For each indicator, sarcopenia was considered to be present when the measure was 2 SDs below the mean. For all four measures, the prevalence of sarcopenia increased with age, both in men and women. The age-associated gradient in prevalence was maximum for muscle power and minimum for calf-muscle area. However, lower extremity muscle power was no better than kneeextension torque or handgrip in the early identification of poor mobility, defined either as walking speed 0.8 m/s or inability to walk at least 1 km without difficulty and without developing symptoms. Optimal cutoff values that can be used in the clinical practice to identify older persons with poor mobility were developed. The findings of the study lay the basis for a cost-effective, clinical marker of sarcopenia based on a measure of isometric handgrip strength. Our findings should be verified in a longitudinal study.
- Advantages of this approach: - Easy to apply - understandable by most physicians Disadvantages This appoach assume that muscle mass is the most important clinical parameter to be assessed. A large body of data demonstrate that the strength generate by a unit of muscle mass is very variable between genders and tend s to decline steadily with aging. The threshold in Bone mineral density used for the for the definition of osteoporosis was selected based on observed risk of hip fracture in longitudinal studies.
- Lady and gentleman, thank you to invite me. Sarcopenia is actually considered to be one of the hallmarks of the aging process. It howerver suprising that in 2009, they is still no consensual definition of sarcopenia.
- I will give the summary of on-going discussion of a groupe conducted by the EUGMS working on a definition of sarcopenia