A two-year longitudinal study on the determinant of bone mass gain at lumbar spine and hip during adolescence: the prevention of osteoporosis from adolescence

对京都3所初中的412名一年级学生和316名高中一年级学生，我们通过腰椎（L2-L4） [LS]和全髋关节[TH]的DXA测量了基线时的骨密度、身高、体重和握力。我们在346所初中中检查了相同的变量。2年后，学生（男生127人，女生219人，随访率为84.0%）和高中生160人（男生77人，女生83人，随访率为50.6%）再访。在LS（初中生：男生=10.4%/年，女生=6.0%/年；高中生：男生=4.2%/年，女生=1.4%/年）和TH（初中生：男生=8.6%/年，女生=5.3%/年；高中生：男生=4.1%/年，女生=2.7%/年），男女均有显著增加；观察不同年级和不同部位骨密度变化率的性别差异。由于初三学生比初三学生更倾向于增加骨密度，因此初三阶段对骨量的增加非常重要。2.初中生骨密度随年龄的增长而增加，而高中生骨密度不随年龄的增长而增加。然而，骨密度的年变化率随着青春期的进展而下降。3.脊柱和髋部骨密度随体重增加而增加。4.初中和高中生活方式越积极的男生和女生，在LS和TH的骨密度和变化率越大。据推测，两个年龄组的体育活动都对青少年的骨骼发育有积极影响。5.初高中阶段充足的钙摄入被认为对骨密度的获得有积极影响；尽管骨密度和钙摄入量之间没有明显的关系。

For 412 first year students from 3 junior high schools and 316 first year high school students in Kyoto, we measured BMD by DXA at the lumbar spine (L2-L4) [LS] and total hip [TH], height, weight, and grip strength at baseline. We examined the same variables in 346 of the junior high school. students (127 boys and 219 girls, follow-up rate=84.0%) and 160 of the high school students (77 boys and 83 girls, follow-up rate=50.6%) again after 2 years respectively.1.There was a significant increase in BMD at the LS (junior high school students: boys=10.4%/yr, girls=6.0%/yr; high school students: boys=4.2%/yr, girls=1.4%/yr) and TH (junior high school students: boys=8.6%/yr, girls=5.3%/yr; high school students boys=4.1%/yr girls=2.7%/yr) in both genders; and the gender differences in the rate of change in BMD at both grades and sites were observed. Since third-year junior high school students tend to increase BMD more than third-year high school students, the junior high school years are very important for bone mass gain. 2.BMD at LS and TH increased with maturity in both genders for junior high school students but not high school students. However, the annual change rates in BMD decreased with progression of puberty. 3.BMD at the spine and hip increased with weight in both sexes for both age groups. 4.Boys and girls with more active lifestyles in junior high and high school showed greater BMD and change rates at LS and TH. Physical activity for both age groups was inferred to positively influence bone development in adolescents. 5.Sufficient calcium intake in the junior high and high school years was considered to influence acquisition of bone density positively; although there was no significant relationship between BMD and calcium intake.