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The Challenge of Understanding Sarcopenia, Muscle Strength and
Disability
Jack M. Guralnik, M.D., Ph.D.
Department of Epidemiology and Public Health
University of Maryland School of Medicine
Domains of Functioning
• Physical
• Cognitive
• Psychological
• Sensory
• Social
Disability
• Expression of a physical or mental limitation in a social context
• The gap between a person’s capabilities and the demands of the environment
IOM, 1991
Disability Domains
• Self-care: ADLs
• Independence living in the
community: IADLs
• Mobility (ambulation) at home and in the community: Mobility disability
Activities of Daily Living: ADLsBasic Self-Care Tasks
• Eating
• Dressing
• Bathing
• Transferring from bed to chair
• Using the toilet
Instrumental Activities of Daily Living: IADLS
• Preparing meals• Shopping• Housekeeping• Managing money• Taking medications• Using the telephone
Prevalence of Difficulty Walking ¼ Mile, NHIS, 1998
Per
cent
Men Women
29.437.5
45.0
57.0
70.2
80.1
0
20
40
60
80
65-74 75-84 85+ 65-74 75-84 85+
Ability to move through one’s environment without assistance
Efficient and reliable locomotion is a fundamental feature of human functioning, and indeed functioning across virtually all animal species
Mobility
Proportion of Persons with Catastrophic and ProgressiveDisability Among Those Who Developed Severe Disability
Catastrophicdisability
Progressivedisability
Pro
por
tion
of t
he s
ever
ely
disa
bled
100
80
60
40
20
0
Source: Ferrucci et al. J Gerontol Med Sci 1996;51A:M123-M130.
Age (years)
69-74 75-79 80-84 85+
M M M M WWWW
Disability
Demographics
Behavioral risk factors
Disease
DisabilityFunctional Limitations
Restrictions in basic physical and mental
actions (ambulate, reach, grasp, climb stairs, speak,
see standard print)
Impairments
Dysfunction and structural abnormalities in specific body
systems (musculoskeletal, cardiovascular, etc.)
Demographics
Behavioral risk factors
Disease
Theoretical Model of the Pathway from Disease to Disability: Nagi
Mean Grip Strength in Nonsurvivors and Survivors at Baseline and Survivors at Follow-up 27 Years Later
Honolulu Heart Program and Honolulu Asia Aging Study
Source: Rantanen et al. J Appl Physiol 1998;85:2047
Mortality Rates in Groups Based on BMI and Hand Grip Strength
Honolulu-Asia Aging Study
Source: Rantanen et al. J Gerontol Med Sci 2000;55:M168-73.
Proportion of Subjects with Functional Limitations in1991-93 According to Grip Strength Tertiles
25 Years Earlier
HighestMiddleLowest
Grip Strength Tertiles
Percent
Unable to Rise from a Chair
Walking Speed 0.4 m/s
Functional Limitations
(3,218 Initially Healthy 45- to 68-year-old Men, HAAS)
Source: Rantanen et al. JAMA 1999;281:558-560.
0 5 10 15 20 25 30
Proportion of Subjects with Disability in 1991-93 Accordingto Grip Strength Tertiles 25 Years Earlier
Highest
Middle
Lowest
Grip Strength Tertiles
Doing HeavyHousehold Work
Self-reported Difficulty
Percent
(3,218 Initially Healthy 45- to 68-year-old Men, Honolulu)
Source: Rantanen et al., JAMA 1999;281:558-560.
Toileting
Dressing
Walking Up 10 Step
Walking 1/2 mile
0 5 10 15 20 25 30
Sarcopenia
• The age-related loss in skeletal muscle
• Sarx = flesh, penia = poverty– IR Rosenberg. Am J Clin Nutr 1989;50(suppl):1231-3– WJ Evans & WW Campbell. J Nutr 1993;123:465-8
The Sarcopenia Hypothesis
• Muscle mass is lost progressively after mid-adulthood
• Muscle mass correlates with strength• Low strength is a hallmark of disability• Many disabling conditions are
associated with accelerated loss of lean mass
Age-related changes in body composition
Age 63 Age 79
John Turner – Weight Lifter
Mid-Femur CT Images from the BLSA (all women with BMI 30-32)
Age=80 Years
Age=55 Years
Age=33 Years
Dual Energy X-ray Absorptiometry (DEXA)
Skeletal muscle mass and distribution in 468 men and women aged 18–88 yrIAN JANSSEN, STEVEN B. HEYMSFIELD, ZIMIAN WANG, and ROBERT ROSS
J Appl Physiol 89:81-88, 2000
Men
Women
The Effect of Bed Rest on Muscle
• Over 2 pounds of muscle in the legs (6.3% decline)
• More than 15% of lower extremity strength
After 10 days of bed rest, healthy older adults lost…
Kortebein et al. JAMA 2007;297:1772-4.
25-34 35-44 45-54 55-64 65-74 75-84 85+
-40%
-35%
-30%
-25%
-20%
-15%
-10%
-5%
0%
5%
Knee Strength
Leg Muscle Mass
Pe
rce
nt
Ch
an
ge
Longitudinal Percent Change in Muscle Strengthby Decade 25-98 yrs.
The Baltimore Longitudinal Study of Aging
Annualized declines in leg lean mass (hatched bar) and muscle strength (black bar) in the Health ABC Study.
Goodpaster BH et al. The Loss of Skeletal Muscle Strength, Mass, and Quality in Older Adults: The Health, Aging and Body Composition Study. J Gerontol A Biol Sci Med Sci. 2006;61:M1059-M1064.
Hazard Ratios for Incident Mobility Limitations by Quartiles of Three Muscle Parameters: Health ABC - WOMEN
Adjusted for: age, race, site, height, total fat mass, education, alcohol, smoking statusphysical activity, prevalent disease, self-rated health, depression, cognition and other parameters.
Visser et al, J Gerontol A Biol Sci Med Sci. 2005 Mar;60(3):324-33
0
0.5
1
1.5
2
2.5
Area Attenuation Strength
Ad
juste
d H
R
Muscle Mass and Muscle Strength are Not Equivalent
• Interventions that increase lean mass don’t necessarily increase strength (e.g. GH).
• Strength increases seen with resistance training precede and are far in excess of measurable changes in muscle mass.
• Voluntary weight loss leads to losses in skeletal mass but not changes in strength.
• Therefore, muscle mass alone is not adequate for characterizing or diagnosing sarcopenia.
European Working Group on Sarcopenia in Older People1
Low Muscle Mass and
Low Muscle Strength orLow Physical Performance
1. Cruz-Jentoft AJ et al. Age and Ageing 2010;39:412-4232. Muscaritoli M et al Clinical Nutrition 2010;29:154-159
ESPEN’s Cachexia-Anorexia & Nutrition in Geriatrics SIGs2
% muscle mass ≥ 2 sd below young adults matched on sex and ethnicity, and
Low gait speed (e.g. < 0.8 m/s over 4 meters)
New Composite Definitions
“See, the problem with doing things to prolong your life is that all the extra years come at the end, when you’re old.”
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