Computed Tomography-Derived Skeletal Muscle Radiodensity Predicts Peak Weight-Corrected Jump Power in Older Adults: The Korean Urban Rural Elderly (KURE) Study.

Affiliation

Choi H(#)(1), Hong N(#)(2), Park N(2), Kim CO(3), Kim HC(4), Choi JY(5), Youm Y(6), Rhee Y(7).
Author information:
(1)Yonsei University College of Medicine, Seoul, South Korea.
(2)Department of Internal Medicine, Severance Hospital, Endocrine Research Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea.
(3)Division of Geriatrics, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
(4)Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, South Korea.
(5)Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea.
(6)Department of Sociology, Yonsei University College of Social Sciences, Seoul, South Korea.
(7)Department of Internal Medicine, Severance Hospital, Endocrine Research Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea. [Email]
(#)Contributed equally

Abstract

Computed tomography (CT)-derived skeletal muscle area (SMA) and skeletal muscle radiodensity (SMD) reflect distinctive quantitative and qualitative characteristics of skeletal muscles. However, data on whether CT-based muscle parameters, especially SMD, can predict muscle function is limited. In a prospective cohort, 1523 community-dwelling older adults who underwent abdominal CT scans and the countermovement two-legged jumping test on a ground reaction force platform were analyzed (mean age 74.7 years, 65.1% women). SMA and SMD were measured at third lumbar vertebra level (L3). Individuals with low jump power (peak weight-corrected jump power < 23.8 W/kg in men and < 19.0 W/kg in women using clinically validated threshold) were older; had lower SMA, SMD, and maximal grip strength values; and had lower chair rise test and timed up and go test performance than those without low jump power. SMD was positively associated with peak weight-corrected jump power (adjusted β = 0.33 and 0.23 per 1 HU increase in men and women, respectively, p < 0.001). One HU decrement in SMD was associated with 10% elevated odds of low jump power (adjusted OR [aOR] 1.10, p < 0.001) after adjusting for age, sex, height, inflammation, and insulin resistance markers, whereas the association of SMA with low jump power was attenuated (aOR 1.00, p = 0.721). SMD showed better discrimination for low jump power than SMA (AUC 0.699 vs. 0.617, p < 0.001), with additional improvement when added to SMA and conventional risk factors (AUC 0.745 to 0.773, p < 0.001). Therefore, CT-measured L3 SMD can be a sensitive surrogate marker for muscle function along with SMA in older adults, which merits further investigation.