Originalien Z Gerontol Geriat DOI 10.1007/s00391-015-0886-z Received: 25 June 2014 Revised: 20 January 2015 Accepted: 3 March 2015
D. Spira1 · K. Norman1 · J. Nikolov1 · I. Demuth1,2 · E. Steinhagen-Thiessen1 · R. Eckardt1
© Springer-Verlag Berlin Heidelberg 2015
Prevalence and definition of sarcopenia in community dwelling older people
1 Charité Research Group on Geriatrics, Charité-Universitätsmedizin, Berlin, Germany 2 Institute of Medical and Human Genetics, Charité-Universitätsmedizin, Berlin, Germany
Data from the Berlin aging study II (BASE-II) Introduction The term sarcopenia was first introduced by Irwin H. Rosenberg and rated as a clinically relevant phenomenon [30]. As understood today, sarcopenia is a syndrome that describes the age-associated loss of muscle mass, muscle strength and muscle function. It is known that from the age of 50 years onwards, muscle mass decreases by 1–2 % annually and muscle strength is reduced by approximately 1.5 % annually between the age of 50 and 60 years [7, 15, 18, 35]. A fundamental characteristic of sarcopenia is the combination of quantitative decline, reflected by the decrease of muscle cells via apoptosis and a reduction of muscle fiber quantity and qualitative decline seen in the decreasing strength that a single muscle fiber can produce in relation to its size [1, 22, 31]. The clinical importance of sarcopenia can easily be imagined if it is taken into account that a certain amount of muscular function is indispensable for all basic activities of daily life. Moreover, sarcopenia is linked with adverse outcomes, such as disability, falls, loss of independence and increased morbidity and mortality [17]. The importance of sarcopenia in health care requires not only a standardized definition but also definitive diagnostic criteria. This is currently part of an on-going scientific debate but the definitions proposed by the European working group on sarcopenia in older people (EWGSOP) and the international working group on sarcopenia (IWGS) are of particular im-
portance [8, 12, 23]. Whereas the definition by the EWGSOP considers muscle mass and strength or function, the definition of the IWGS focuses on muscle mass and function. Function is usually reflected by gait speed and mobility which was also taken into account in the consensus conference convened by the Society of Sarcopenia, Cachexia and Wasting Disorders that concluded that sarcopenia with limited ability should be considered an important clinical entity [23]. The aim of this study was to determine the prevalence of sarcopenia in a cohort of community dwelling old people living in Berlin, Germany, using these established diagnostic criteria and to discuss the variable impact on the prevalence. Furthermore, the impact of the respective sarcopenia definitions on self-reported capabilities in physical performance was also studied.
Material and methods Participants All participants gave written informed consent and the ethics committee of the Charité Universitätsmedizin Berlin approved the study (approval number EA2/029/09). Altogether 1405 healthy participants from the Berlin aging study II (BASE-II) recruited between 2009 and 2013 were included in this analysis. The BASE II is a prospective epidemiological study to investigate factors associated with healthy or unhealthy aging in residents of
the greater metropolitan area of Berlin as described previously in detail [3]. Briefly, eligibility criteria at the time of recruitment were healthy community dwelling, well-functioning older subjects aged between 60 and 80 years. Participants were excluded if they (1) reported difficulty walking one quarter of a mile without assistance, (2) suffered from Parkinson's disease, had experienced stroke or myocardial infarction, (3) undergone head, heart or vascular surgery or (4) suffered from dementia or malignant diseases. Anthropometric measurements. Body weight was measured in light clothes with a portable electronic scale to the nearest 0.1 kg and height was determined to the nearest 0.1 cm using an electronic weighing and measuring station (seca 764, seca, Hamburg, Germany). Weight and height were used to calculate body mass index (BMI) as weight (kg)/height (m)2. Body composition. Body composition was assessed with dual-energy X-ray absorptiometry (DXA Hologic® QDR® DiscoveryTM, Hologic, Bedford, MA). A trained technician performed the DXA measurement protocol. Appendicular skeletal muscle mass (ASM) in kilograms was calculated as the sum of the regional muscle mass of the four limbs and the skeletal muscle mass index (SMI) as ASM/ height2 (kg/m2) [2]. Dr. Dominik Spira and Priv.-Doz. Dr. Kristina Norman contributed equally to this work. Zeitschrift für Gerontologie und Geriatrie
1
Originalien Table 1 Characteristics of the study population according to gender (mean ± standard devia-
tion)
Age (years) Body mass index (kg/m2) Skeletal muscle mass index (kg/m2) Hand grip strength (kg) Timed up and go test (s)
Men n = 622 68.4 ± 3.6 27.3 ± 3.7 7.77 ± 0.77 37.6 ± 6.6 7.8 ± 1.4
Hand grip strength. Maximum isometric hand grip strength was measured in both hands with a Smedley Dynamometer (Scandidact, Denmark) and the highest value was chosen. The subjects performed the test while standing comfortably with shoulders adducted and neutrally rotated, the elbow flexed to 90°, forearms and wrists in a neutral position. The subjects were instructed to perform a maximum isometric contraction, the test was performed three times and the highest value was recorded. The cut-off values suggested by Fried et al. [13] and also recommended by Cruz-Jentoft et al. [8] were used to identify reduced grip strength. Timed up and go test. Since gait speed was not available for all participants but in order to fulfill the requirements of both consensus statements [6, 29] to combine muscle mass with a functional parameter, the timed up and go test (TUG) was used as part of the comprehensive geriatric assessment. The time in seconds taken to stand up from a standard chair, walk a distance of 3 m, turn, walk back to the chair and sit down was measured for the subjects. Participants who completed the test in less than 10 s were deemed freely mobile [28]. Self-reported physical performance. Participants were asked whether they had difficulties performing certain physical tasks, such as lifting or carrying, bending or kneeling, climbing several flights of stairs, walking (> 1 km) or performing strenuous activities, such as lifting heavy objects, walking fast or running (graded as severe/moderate/no difficulties). Definitions of sarcopenia. Sarcopenia (low SMI only) was defined according to the definition by Baumgartner et al. [2]:
2
Zeitschrift für Gerontologie und Geriatrie
Women n = 783 67.9 ± 3.6 26.6 ± 4.6 6.08 ± 0.79 23.5 ± 4.5 7.6 ± 1.3
P-value 0.005 0.001 0.0001 0.0001 0.005
SMI ≤ 7.26 kg/m2 in men and ≤ 5.5 kg/m2 in women. Sarcopenia with limited mobility was defined as low SMI and slow TUG test performance (> 10 s): sarcopenia with reduced strength was determined by low SMI and decreased handgrip strength as suggested by Fried et al. [13].
Statistical analyses Statistical analysis was carried out using the software package IBM Statistics SPSS 21. Data are given in percent or as mean and standard deviation. Bivariate relationships between variables were analyzed using Spearman’s correlation. In order to compare means between groups, Student’s t-test was employed. The χ2-test was used to compare percentages between groups. An acceptable level of statistical significance was established a priori at p
D. Spira1 · K. Norman1 · J. Nikolov1 · I. Demuth1,2 · E. Steinhagen-Thiessen1 · R. Eckardt1
© Springer-Verlag Berlin Heidelberg 2015
Prevalence and definition of sarcopenia in community dwelling older people
1 Charité Research Group on Geriatrics, Charité-Universitätsmedizin, Berlin, Germany 2 Institute of Medical and Human Genetics, Charité-Universitätsmedizin, Berlin, Germany
Data from the Berlin aging study II (BASE-II) Introduction The term sarcopenia was first introduced by Irwin H. Rosenberg and rated as a clinically relevant phenomenon [30]. As understood today, sarcopenia is a syndrome that describes the age-associated loss of muscle mass, muscle strength and muscle function. It is known that from the age of 50 years onwards, muscle mass decreases by 1–2 % annually and muscle strength is reduced by approximately 1.5 % annually between the age of 50 and 60 years [7, 15, 18, 35]. A fundamental characteristic of sarcopenia is the combination of quantitative decline, reflected by the decrease of muscle cells via apoptosis and a reduction of muscle fiber quantity and qualitative decline seen in the decreasing strength that a single muscle fiber can produce in relation to its size [1, 22, 31]. The clinical importance of sarcopenia can easily be imagined if it is taken into account that a certain amount of muscular function is indispensable for all basic activities of daily life. Moreover, sarcopenia is linked with adverse outcomes, such as disability, falls, loss of independence and increased morbidity and mortality [17]. The importance of sarcopenia in health care requires not only a standardized definition but also definitive diagnostic criteria. This is currently part of an on-going scientific debate but the definitions proposed by the European working group on sarcopenia in older people (EWGSOP) and the international working group on sarcopenia (IWGS) are of particular im-
portance [8, 12, 23]. Whereas the definition by the EWGSOP considers muscle mass and strength or function, the definition of the IWGS focuses on muscle mass and function. Function is usually reflected by gait speed and mobility which was also taken into account in the consensus conference convened by the Society of Sarcopenia, Cachexia and Wasting Disorders that concluded that sarcopenia with limited ability should be considered an important clinical entity [23]. The aim of this study was to determine the prevalence of sarcopenia in a cohort of community dwelling old people living in Berlin, Germany, using these established diagnostic criteria and to discuss the variable impact on the prevalence. Furthermore, the impact of the respective sarcopenia definitions on self-reported capabilities in physical performance was also studied.
Material and methods Participants All participants gave written informed consent and the ethics committee of the Charité Universitätsmedizin Berlin approved the study (approval number EA2/029/09). Altogether 1405 healthy participants from the Berlin aging study II (BASE-II) recruited between 2009 and 2013 were included in this analysis. The BASE II is a prospective epidemiological study to investigate factors associated with healthy or unhealthy aging in residents of
the greater metropolitan area of Berlin as described previously in detail [3]. Briefly, eligibility criteria at the time of recruitment were healthy community dwelling, well-functioning older subjects aged between 60 and 80 years. Participants were excluded if they (1) reported difficulty walking one quarter of a mile without assistance, (2) suffered from Parkinson's disease, had experienced stroke or myocardial infarction, (3) undergone head, heart or vascular surgery or (4) suffered from dementia or malignant diseases. Anthropometric measurements. Body weight was measured in light clothes with a portable electronic scale to the nearest 0.1 kg and height was determined to the nearest 0.1 cm using an electronic weighing and measuring station (seca 764, seca, Hamburg, Germany). Weight and height were used to calculate body mass index (BMI) as weight (kg)/height (m)2. Body composition. Body composition was assessed with dual-energy X-ray absorptiometry (DXA Hologic® QDR® DiscoveryTM, Hologic, Bedford, MA). A trained technician performed the DXA measurement protocol. Appendicular skeletal muscle mass (ASM) in kilograms was calculated as the sum of the regional muscle mass of the four limbs and the skeletal muscle mass index (SMI) as ASM/ height2 (kg/m2) [2]. Dr. Dominik Spira and Priv.-Doz. Dr. Kristina Norman contributed equally to this work. Zeitschrift für Gerontologie und Geriatrie
1
Originalien Table 1 Characteristics of the study population according to gender (mean ± standard devia-
tion)
Age (years) Body mass index (kg/m2) Skeletal muscle mass index (kg/m2) Hand grip strength (kg) Timed up and go test (s)
Men n = 622 68.4 ± 3.6 27.3 ± 3.7 7.77 ± 0.77 37.6 ± 6.6 7.8 ± 1.4
Hand grip strength. Maximum isometric hand grip strength was measured in both hands with a Smedley Dynamometer (Scandidact, Denmark) and the highest value was chosen. The subjects performed the test while standing comfortably with shoulders adducted and neutrally rotated, the elbow flexed to 90°, forearms and wrists in a neutral position. The subjects were instructed to perform a maximum isometric contraction, the test was performed three times and the highest value was recorded. The cut-off values suggested by Fried et al. [13] and also recommended by Cruz-Jentoft et al. [8] were used to identify reduced grip strength. Timed up and go test. Since gait speed was not available for all participants but in order to fulfill the requirements of both consensus statements [6, 29] to combine muscle mass with a functional parameter, the timed up and go test (TUG) was used as part of the comprehensive geriatric assessment. The time in seconds taken to stand up from a standard chair, walk a distance of 3 m, turn, walk back to the chair and sit down was measured for the subjects. Participants who completed the test in less than 10 s were deemed freely mobile [28]. Self-reported physical performance. Participants were asked whether they had difficulties performing certain physical tasks, such as lifting or carrying, bending or kneeling, climbing several flights of stairs, walking (> 1 km) or performing strenuous activities, such as lifting heavy objects, walking fast or running (graded as severe/moderate/no difficulties). Definitions of sarcopenia. Sarcopenia (low SMI only) was defined according to the definition by Baumgartner et al. [2]:
2
Zeitschrift für Gerontologie und Geriatrie
Women n = 783 67.9 ± 3.6 26.6 ± 4.6 6.08 ± 0.79 23.5 ± 4.5 7.6 ± 1.3
P-value 0.005 0.001 0.0001 0.0001 0.005
SMI ≤ 7.26 kg/m2 in men and ≤ 5.5 kg/m2 in women. Sarcopenia with limited mobility was defined as low SMI and slow TUG test performance (> 10 s): sarcopenia with reduced strength was determined by low SMI and decreased handgrip strength as suggested by Fried et al. [13].
Statistical analyses Statistical analysis was carried out using the software package IBM Statistics SPSS 21. Data are given in percent or as mean and standard deviation. Bivariate relationships between variables were analyzed using Spearman’s correlation. In order to compare means between groups, Student’s t-test was employed. The χ2-test was used to compare percentages between groups. An acceptable level of statistical significance was established a priori at p
