Sarcopenic obesity predicts instrumental activities of daily living disability in the elderly.
OBJECTIVE
To determine the association of sarcopenic obesity with the onset of Instrumental Activities of Daily Living (IADL) disability in a cohort of 451 elderly men and women followed for up to 8 years.


METHODS
Sarcopenic obesity was defined at study baseline as appendicular skeletal muscle mass divided by stature squared <7.26 kg/m2 in men and 5.45 kg/m2 in women and percentage body fat greater than the 60th percentile of the study sample (28% body fat in men and 40% in women). Incident disability was defined as a loss of two or more points from baseline score on the IADL. Subjects with disability at baseline (scores < 8) were excluded. Cox proportional hazards analysis was used to determine the association of baseline sarcopenic obesity with onset of IADL disability, controlling for potential confounders.


RESULTS
Subjects with sarcopenic obesity at baseline were two to three times more likely to report onset of IADL disability during follow-up than lean sarcopenic or nonsarcopenic obese subjects and those with normal body composition. The relative risk for incident disability in sarcopenic obese subjects was 2.63 (95% confidence interval, 1.19 to 5.85), adjusting for age, sex, physical activity level, length of follow-up, and prevalent morbidity.


CONCLUSIONS
This is the first study, to our knowledge, to indicate that sarcopenic obesity is independently associated with and precedes the onset of IADL disability in the community-dwelling elderly. The etiology of sarcopenic obesity is unknown but may include a combination of decreases in anabolic signals and obesity-associated increases in catabolic signals in old age.
Baumgartner
Richard N
RN
Aging and Genetic Epidemiology Program, Division of Epidemiology and Preventive Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131,USA. rbaumgartner@salud.unm.edu
Wayne
Sharon J
SJ
Waters
Debra L
DL
Janssen
Ian
I
Gallagher
Dympna
D
Morley
John E
JE
D000203:Activities of Daily Living; D000273:Adipose Tissue; D000368:Aged; D000375:Aging; D001168:Arthritis / Q000453:epidemiology; D001823:Body Composition; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D006233:Persons with Disabilities / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology; D008875:Middle Aged; D018908:Muscle Weakness / Q000150:complications*; D009133:Muscular Atrophy / Q000150:complications*; D009765:Obesity / Q000150:complications*; D016016:Proportional Hazards Models; D012306:Risk