Longitudinal study of annual change of bone mass at weight-bearing and non-weight-bearing sites in college women

To examine the relationship between sports activity and bone mass acquisition, we observed one-year changes in the bone mineral content and density (BMC and BMD) of weight-bearing and non-weight-bearing bone in 68 college women who had participated in various sports since the age of 18.5 years on average. Based on their sports experience, the subjects were divided into four groups :Group A: 18 students who have not had participated in any kind of sports activity since junior high school days;Group B:8 students who had participated in team sports at junior and senior high school, then stopped practicing after entering college;Group C:14 students who had participated in team sports since junior high school;Group D:28 rhythmic sports gymnasts. Whole-body and regional BMC in the head, trunk, arms and legs, and BMD of the lumbar spine and proximal femur were measured using an XR-26 DXA scanner. Height, weight and calcium intake were similar among the four groups. and during the experiment their values changed little. With regard to annual changes in BMC and BMD for weight-bearing regions: 1) In Group A, no significant increases were observed in any of the body regions: 2) In Groups B and C, only the lumbar spine showed a significant increase. Comparing the changes in BMD in these two groups, Group C showed a larger increase than Group B, although the value did not reach statistical significance; 3) In Group D, significant increases in BMD for the lumbar spine and femoral neck and in BMC for the trunk and legs were found. The annual changes in BMD were significantly higher than Group A. As to annual changes in non-weight-bearing bones such as those in the head and arms, there were not significant differences among the groups. These data indicate that sports practice may affect changes in bone mass in weight-bearing regions in female college students. Furthermore, it is possible that the amount and quality of sports training may influence the peak bone mass and its timing.