Osteoporosis: An Overview

Abstract

Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue. Approximately 8 million women and 2 million men in the United States have osteoporosis, and 34 million persons have osteopenia. Primary osteoporosis is the result of bone loss related to the decline in gonadal function associated with aging. Secondary osteoporosis may result from chronic diseases, exposures, or nutritional deficiencies that adversely impact bone metabolism. Various factors are known to influence bone mass accumulation during growth which include genetic factors, endocrine factors (sex steroids, calcitriol, insulin-like growth factor-I (IGF-I)), mechanical forces (physical activity, body weight). The ideal screening method to characterize bone status would include parameters of bone density, bone microarchitecture, markers of bone formation and marks of bone resorption. The favored methods of bone evaluation are DEXA, CXD and one another low cost method of screening in which skin fold thickness (SFT) is measured over the fourth metacarpus with Holtain Tanner Whitehouse calipers. Non pharmacological and pharmacological treatment may improve the bone loss in osteoporosis. The biological and biomechanical characteristics of orthopaedic implants, bone-graft substitutes (with or without osteogenic bone morphogenetic proteins) can be tested on large numbers of animals maintained with a level of experimental control, impossible in human clinical research. Various animal models mainly used for osteoporosis are immobilized rat model, nonhuman primate ovariectomized model the ovariectomized mouse model, the senescence accelerated mouse (SAM/P6) model, the mouse glucocorticoid treated model.