Bone quality: A determinant for certain risk factors for bone fragility

Abstract

Low bone quantity alone is insufficient cause for fragility fractures. This paper examines the role of bone quality in the fracture risk associated with age, sex, and race. Aspects of bone quality to be considered are bone architecture, matrix, mineralization, and fatigue damage. The trabecular network becomes progressively disconnected and weaker with age. Death of old osteocytes leads to hypermineralization and brittleness of bone. The stability of bone collagen declines with age, and unremodeled bone accumulates fatigue damage. The lower bone fragility rates in males than in females may be due to a combination of the larger male skeleton, greater cortical bone density after age 60 years, and greater bone turnover which would replace fatigue damaged bone. Fragility fracture rates in American and African blacks are lower than in whites, bone mineral density (BMD) is greater in American but not in African blacks (except for hip BMD), and American blacks have lower and African blacks higher bone turnover compared to whites. In South African blacks, trabeculae are thicker and better connected and trabecular bone undergoes less destructive age changes than in whites. To reconcile the disparate findings in American and African blacks we suggest that both groups have a genetic tendency to greater BMD than whites; American blacks realize this potential and African blacks do not, possibly because of calcium deficiency. Consequent high turnover removes fatigue damage and so improves bone quality. Weight-bearing activity in African blacks may be responsible for good hip bone density and thick trabeculae.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential Effects of Bone Structural and Material Properties on Bone Competence in C57BL/6 and C3H/He Inbred Strains of Mice

“…4 and 5). Since the two strains showed similar variation in strength, this implies that strength in C3H bone, much more than in B6, is determined not only by structural but also by other bone properties, often referred to as ''bone quality'' [46][47][48]. The term ''bone quality'' incorporates the effects of ultrastructural properties such as mineralization, microporosity, microdamage, the distribution and activity of the three main cell types in bone (osteoclasts, osteoblasts, and osteocytes), and collagen quality.…”

Bone quantity and quality in past populations

“…The idea of a compensatory mechanism to maintain bone quality in the face of reduced bone mass has been similarly suggested in modern ethnic groups, such as African blacks (Schnitzler, 1993). Compensatory mechanisms to protect bone quality in past populations could thus have been aided and further maintained by activity levels and physical demands of lifestyle.…”

Low Serum Levels of Undercarboxylated Osteocalcin in Postmenopausal Osteoporotic Women Receiving an Inhibitor of Bone Resorption

“…Bone quality includes structural strength such as microarchitecture, and intrinsic material properties such as degree of mineralization, collagen crosslinkage, and damage accumulation (Schnitzler 1993;Saito et al 2006).…”