[A comparison of fat and muscle thickness in Japanese and American women].

The purpose of this study was to investigate the ethnic differences in the body composition, thickness of subcutaneous fat and muscle between Japanese and American white females. Thirty-six Japanese (aged 20-30 years) and 42 American white females (aged 20-29 years) served as subjects. Percentage of fat weight (%fat) and fat free weight (FFW) were assessed by hydrostatic weighing. Subcutaneous fat and muscle thickness were measured by using B-scan ultrasound equipment with a 5MHz transducer at eight sites: forearm, biceps, triceps, subscapular, abdomen, quadriceps, hamstrings and posterior calf. There were no significant differences in %fat between Japanese and American subjects. However, American subjects had significantly higher values in FFW compared to Japanese. The Americans showed higher muscle thickness than Japanese at every site and higher fat thickness of biceps, triceps and hamstrings compared to Japanese subjects. For fat thickness at the abdomen, however, Japanese indicated significantly higher values than American. In both Japanese and Americans, relative values of fat weight (FW) and FFW per unit of height were significantly related to each of the sum of fat and muscle thicknesses obtained from every measurement site respectively. There were no differences in fat thickness at a given FW/height between Japanese and Americans.(ABSTRACT TRUNCATED AT 250 WORDS)