Related Experiment Video
Updated: Jul 30, 2026
Method and Instrumented Fixture for Femoral Fracture Testing in a Sideways Fall-on-the-Hip Position
Published on: August 17, 2017
Bone strength and its determinants in pre- and early pubertal boys and girls
Heather Macdonald1, Saija Kontulainen, Moira Petit
1School of Human Kinetics, University of British Columbia, Vancouver, Canada. hmacdona@interchange.ubc.ca
Abstract:
Higher fracture rates in women than men may be related to a sex difference in bone strength that is thought to emerge during growth. However, sexual dimorphism in bone strength and the determinants of bone strength in boys and girls are not well understood. Thus, our objectives were to (1) compare tibial bone strength and its components (geometry and density) between pre- and early pubertal boys and girls and (2) identify the contribution of muscle cross-sectional area and other modulating factors to bone outcomes. We used pQCT to assess the distal tibia (8%) and tibial midshaft (50%) in 424 Asian and Caucasian pre- and early pubertal boys and girls. Our primary outcomes were bone strength index (BSI, mg2/mm(4)) at the distal tibia and strength strain index (SSI, mm3) at the midshaft. We also assessed components of bone strength including bone geometry [total (ToA) and cortical (CoA) cross-sectional areas, mm2] and total (ToD, mg/cm3) and cortical (CoD, mg/cm3) density. We used ANCOVA to compare bone outcomes between boys and girls in each maturity group (PRE or EARLY pubertal by Tanner stage) and multiple regression to evaluate the contribution of muscle cross-sectional area (MCSA, mm2 by pQCT), maturity, ethnicity, physical activity, dietary calcium, and vertical jump height to bone outcomes. After adjusting for tibial length and MCSA, bone strength indices were 6-15% (P < 0.05) greater in PRE and EARLY boys compared with PRE and EARLY girls. The sex difference in bone strength was due largely to greater bone areas (4-6%) in boys. At the distal tibia ToD was significantly greater in PRE boys (6%, P < 0.001) compared with PRE girls and at the midshaft CoD was slightly greater in both PRE and EARLY girls (1%, P = 0.01). After adjusting for tibial length, MCSA was the primary explanatory variable of tibial bone geometry and strength in both sexes accounting for 10-16% of the variance. The influence of maturity, ethnicity, physical activity, and dietary calcium on pQCT bone outcomes was small and was both site- and sex-specific. Sexual dimorphism in tibial bone strength is evident in prepuberty. Our results are consistent with a functional model of bone development in which bone adapts its geometry and strength to withstand challenges from muscle forces during growth.
Related Concept Videos
01:10Nature and Nurture
01:29Bone Formation by Intramembranous Ossification
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...
01:29Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:17Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
01:09Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:20Introduction to the Skeletal System
Components of the Skeletal System
Bone, or osseous tissue, is a hard connective tissue that forms an internal support structure for the human body. Bones shield vulnerable organs and soft tissue from external forces. For example, the vertebral bones protect and support the spinal cord.
Cartilage, a semi-rigid connective tissue found in regions such as...