Relation between body composition and age in healthy Japanese subjects

Objective: To describe the relation between body composition and age measur ed by dual-energy X-ray absorptiometry (DXA) in healthy Japanese adults. Design: Cross-sectional study. Subjects and measurements: The subjects were 2411 healthy Japanese adults ( males 625, females 1786, age 20 -79 y) who attended the Fukuoka Health Prom otion Center, Fukuoka, Japan for health check-up. Body composition was dete rmined by DXA (QDR-2000, Hologic) for the whole body and three anatomical r egions of arms, legs and trunk. Results: The mean Values of body mass index (BMI) and percentage fat mass ( %FM) were 23.2 +/- 3.1 (s.d.) kg/m(2) and 21.8 +/- 6.8% for males and 22.1 +/- 3.3 kg/m(2) and 32.0 +/- 7.5% for females, respectively. For males, cur vilinear relations with the peaks in their forties or fifties were seen for the variables associated adiposity, ie BMI, waist and hip circumference, w aist-hip ratio, total or regional fat mass (FM), %FM and ratio of trunk FM to leg FM. For females, most of these variables increased linearly in older subjects. Lean mass (LM), bone mineral content (BMC) and bone mineral dens ity (BMD) of the whole body and appendicular LM were relatively constant un til the forties and then decreased in both sexes. The rates of decrease in the total or appendicular LM were larger for males than for females, wherea s those in BMC or BMD were larger for females than for males. Conclusions: This study presents the first detailed data on body compositio n in Japanese, which may be useful when comparing with populations of diffe rent racial and ethnic backgrounds and studying ill subjects.