COMPARISON OF SKELETAL MUSCLE MASS TO FAT-FREE MASS RATIO BETWEEN JAPANESE-BRAZILIANS AND JAPANESE
T. Abe, Y. Kawakami, M. Bass, M. Kondo, T. Fukunaga
J Aging Res Clin Practice 2013;2(1):3-6
Background: It is unclear whether there are differences in absolute and relative skeletal muscle mass (SMM) between Japanese-Brazilians living in Brazil and Japanese living in Japan. Objective: To compare the SMM to fat-free mass (FFM) ratio as well as body composition. Design, setting, and participants: Eighty-four Japanese living in Tokyo and 85 Brazilians and 28 Japanese-Brazilians living in Sao Paulo were recruited for this cross-sectional study. Measurements: Muscle thickness (MTH) and subcutaneous fat thickness (FTH) were measured by B-mode ultrasound at nine anatomical sites on the anterior and posterior aspects of the body. Percentage body fat was estimated from FTH, and FFM was calculated. Total SMM was estimated using an ultrasound-derived prediction equation from MTH. Results: Body mass index were similar among the ethnic groups in men and women, while percent body fat was lower in Japanese than in Brazilians and Japanese-Brazilians. In men, absolute FFM and SMM were lower in Japanese-Brazilians than their Japanese and Brazilian counterparts. In women, there was no significant difference in absolute FFM among ethnic groups, but absolute SMM was lower in Brazilians and Japanese-Brazilians than in Japanese. As a result, the SMM:FFM ratio was lower in Brazilians and Japanese-Brazilians than in Japanese in men and women. Conclusion: SMM:FFM ratio was lower in both Brazilians and Japanese-Brazilians compared to Japanese, which may be associated with environmental factors.