Bone mineral density and osteo sono assessment index in adolescents

The standard value for bone mineral density in the distal radius (R-BMD) and the osteo sono assessment index (OSI) in the os calcaneus for each sex and age in teenagers have not yet been fully reported. The R-BMD and OSI of junior and senior high school students were measured by dual energy X-ray absorptiometry (DEXA) or by a quantitative ultrasound technique. Subjects measured by DEXA included 635 junior and senior high school students (274 males and 361 females, aged 12-17 years). Ultrasound measurements were made for 2878 subjects (1733 males, 1145 females, aged 12-18 years). All subjects filled out questionnaires about their past history, family history, past and present eating habits, sports activities, and for females, the presence of menses, regularity of menses, and so on. The R-BMD in 15- to 17-year-old males was significantly higher than that in females. The R-BMD rate of increase in males was almost linear; the rate of increase in females was significantly highest from ages 12 to 13, after which R-BMD increased gradually. The OSI in 15- to 18-year-old males was significantly higher than that in females. The OSI rate of increase in males was almost linear from ages 12 to 17. The OSI in females, except in 14-year-olds, was roughly equal at each age. The OSI was significantly higher in those who regularly participated in sports, either currently or in the past. It was significantly higher in those who previously or currently consumed milk on a daily basis compared with those who had consumed little or no milk. To prevent osteoporosis, increasing peak bone mass is very important. Adequate calcium intake from dairy products which are rich in calcium and absorbed easily, and exercise in adolescence, are expected to result in increased bone formation and increased OSI.