Low skeletal muscle mass associates with low femoral neck strength, especially in older Korean women: the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV).
CONCLUSIONS
Data gathered from a nationally representative cohort demonstrated that subject with low skeletal muscle mass had consistently low femoral neck composite strength indices for compression, bending, and impact, especially in older women, supporting the highly integrated nature of skeletal muscle and bone.


BACKGROUND
Skeletal muscle and bone interact mechanically and functionally. The present study was performed to investigate the association between muscle mass and femoral neck composite strength indices using a nationally representative cohort.


METHODS
This is a population-based, cross-sectional study from Korea National Health and Nutrition Examination Surveys, including 1,275 Koreans (674 women and 601 men) aged 50 years or older. Femoral neck axis length and width were measured by hip DXA scans and were combined with BMD, body weight, and height to create composite indices of femoral neck strength relative to load in three different failure modes: compression, bending, and impact. Presarcopenia was defined as an appendicular skeletal muscle mass (ASM) divided by body weight that was less than 1 SD below the sex-specific mean for young adults.


RESULTS
After adjusting for confounders, women with presarcopenia had consistently lower indices for compression strength (CSI), bending strength (BSI), and impact strength (ISI) than women without this condition. Men with presarcopenia had a lower ISI value than men without presarcopenia. Multiple regression analyses revealed that lower relative skeletal muscle mass (ASM/weight) associated significantly with lower values for all three femoral neck composite indices in women and with lower CSI and ISI in men.


CONCLUSIONS
These findings provide the first clinical evidence for the notion that age-related low muscle mass may increase the risk of osteoporotic hip fractures by decreasing femoral neck strength relative to load, especially in older women, and support the highly integrated nature of skeletal muscle and bone.
Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap2-Dong Songpa-Gu, 138-736, Seoul, South Korea.
B-J
BJ
Kim
S H
SH
Ahn
H M
HM
Kim
S H
SH
Lee
J-M
JM
Koh
D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry / Q000379:methods; D015519:Bone Density / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000473:pathology / Q000503:physiopathology*; D006621:Hip Joint / Q000473:pathology; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009749:Nutrition Surveys; D009929:Organ Size / Q000502:physiology; D055948:Sarcopenia / Q000473:pathology / Q000503:physiopathology*; D016474:Weight-Bearing / Q000502:physiology