Bone health is determined by influences that accumulate over one's entire lifetime. Numerous factors including age, heredity, nutrition, physical activity, sex steroids and other medical problems all influence the possibility of an individual developing osteoporosis. Fractures due to minimal trauma are the important consequence of osteoporosis, but the risk of fractures is also determined by many non-skeletal risk factors such as body size and the frequency of injury. We now have effective therapeutic options to prevent bone loss and to reduce fracture risk. Assessing risk factors for both osteoporosis and for fractures allows clinicians to identify individuals for whom these therapies are most appropriate.