Appendicular skeletal muscle mass and insulin resistance in an elderly korean population: the korean social life, health and aging project-health examination cohort.
BACKGROUND
Increasing evidence supports an association between age-related loss of muscle mass and insulin resistance. However, the association has not been fully investigated in the general population. Thus, we investigated the association between appendicular skeletal muscle mass (ASM) and insulin resistance in an elderly Korean population.


METHODS
This cross-sectional study included 158 men (mean age, 71.8) and 241 women (mean age, 70.6) from the Korean Social Life, Health and Aging Project, which started in 2011. In this study, ASM was measured by bioelectrical impedance analysis and was analyzed in three forms: ASM (kg), ASM/height(2) (kg/m(2)), and ASM/weight (%). The homeostasis model assessment of insulin resistance (HOMA-IR) was used as a measure of insulin resistance. The relationships between the ASM values and the HOMA-IR were investigated by multiple linear regression models.


RESULTS
The HOMA-IR was positively associated with ASM (β=0.43, P<0.0001) and ASM/height(2) (β=0.36, P<0.0001) when adjusted for sex and age. However, after additional adjustment for body weight, HOMA-IR was inversely associated with ASM (β=-0.43, P<0.001) and ASM/height(2) (β=-0.30, P=0.001). Adjustment for other potential confounders did not change these associations. Conversely, HOMA-IR was consistently and inversely associated with ASM/weight before and after adjustment for other potential confounders.


CONCLUSIONS
Our results support the idea that lower skeletal muscle mass is independently associated with insulin resistance in older adults. When evaluating sarcopenia or muscle-related conditions in older adults, their whole body sizes also need to be considered.
Department of Public Health, Yonsei University Graduate School, Seoul, Korea. ; Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea.
Seung Won
SW
Lee
Department of Sociology, Yonsei University College of Social Sciences, Seoul, Korea.
Yoosik
Y
Youm
Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
Won Joon
WJ
Lee
Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
Wungrak
W
Choi
Department of Clinical Nursing Science, Yonsei University College of Nursing, Seoul, Korea.
Sang Hui
SH
Chu
Division of Silver Industry, Kangnam University, Yongin, Korea.
Yeong-Ran
YR
Park
Severance Institute for Vascular and Metabolic Research, Yonsei University College of Medicine, Seoul, Korea. ; Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea. ; Cardiovascular and Metabolic Diseases Etiology Research Center, Yonsei University College of Medicine, Seoul, Korea.
Hyeon Chang
HC
Kim
Aged; Insulin resistance; Korea; Muscle mass; Sarcopenia