A Longitudinal Study on Bone Mineral Density at Lumbar Spine and Total Hip and its Determinants in Japanese Adolescents − Focus on Sports Activity at Junior High School and High School −
【Supercategory：7. DESCENTE SPORTS SCIENCE Subcategory：7.26 Vol.26】
Aim: Puberty is considered to be an important growth period with major changes in both lifestyle and the acquisition of peak bone mass. At present, there is a lack of quantitative and qualitative information concerning those topics in Japanese children and adolescents. The purpose of the present study was to clarify associations between sports activity in junior high school and high school, and bone mineral density (BMD) and the rate of change in BMD at the lumbar spine and total hip in high school age.
Methods: For 160 third grade students of high school in Kyoto, Japan, we measured BMD by DXA (QDR4500, Hologic) at the lumbar spine (L2-L4) and total hip, height, weight and grip strength (follow up study). Past and present history of illness, lifestyle factors such as dietary calcium intake and exercise habits, and information on maturity were obtained from detailed interviews. The same variables were examined in the first grade, 2 years before (baseline study). We analyzed 156 third grade students (75 boys and 81 girls) who had no disease and were not on medication affecting bone metabolism.
Results: There was significant increase in BMD at the lumbar spine (boys: 4.2%/yr, girls: 1.4%/yr) and total hip (boys: 4.1%/yr, girls: 2.7%/yr) in both genders, but the annual change rates of BMD in high school decreased in comparison with junior high school age. When BMD and the annual change rates in BMD was adjusted for weight and maturity by the analysis of covariance, the boys and girls with more sports active lifestyle in their junior high school and high school age showed greater BMD of spine and hip at baseline and follow up. In multiple regression analyses, sports activity in their junior high school and high school had a significant positive independent effect on BMD at baseline and follow up of both genders and the annual change rates in BMD of girls at both skeletal sites.
Conclusions: Although there was significant increase in BMD at the lumbar spine and total hip in both genders, it was suggested that the peak of the increase in BMD passed in the high school age. Sports activity in junior high school and high school age was the important determinant of bone development in adolescents.
DESCENTE SPORTS SCIENCE Vol.26/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
Methods: For 160 third grade students of high school in Kyoto, Japan, we measured BMD by DXA (QDR4500, Hologic) at the lumbar spine (L2-L4) and total hip, height, weight and grip strength (follow up study). Past and present history of illness, lifestyle factors such as dietary calcium intake and exercise habits, and information on maturity were obtained from detailed interviews. The same variables were examined in the first grade, 2 years before (baseline study). We analyzed 156 third grade students (75 boys and 81 girls) who had no disease and were not on medication affecting bone metabolism.
Results: There was significant increase in BMD at the lumbar spine (boys: 4.2%/yr, girls: 1.4%/yr) and total hip (boys: 4.1%/yr, girls: 2.7%/yr) in both genders, but the annual change rates of BMD in high school decreased in comparison with junior high school age. When BMD and the annual change rates in BMD was adjusted for weight and maturity by the analysis of covariance, the boys and girls with more sports active lifestyle in their junior high school and high school age showed greater BMD of spine and hip at baseline and follow up. In multiple regression analyses, sports activity in their junior high school and high school had a significant positive independent effect on BMD at baseline and follow up of both genders and the annual change rates in BMD of girls at both skeletal sites.
Conclusions: Although there was significant increase in BMD at the lumbar spine and total hip in both genders, it was suggested that the peak of the increase in BMD passed in the high school age. Sports activity in junior high school and high school age was the important determinant of bone development in adolescents.
DESCENTE SPORTS SCIENCE Vol.26/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
| Researcher | Hiroshi Naka*1, Masayuki Iki*2, Akemi Morita*2, Junko Tamaki*2, Yukihiro Ikeda*2 |
|---|---|
| University or institution | *1 Kyoto University of Education, *2 Department of Public Health, Kinki University School of Medicine |
Keywords
Puberty, peak bone mass, sports activity, bone mineral density(BMD)