Osteoporosis is a disease of bone in which the bone mineral density (BMD) is reduced, bone microarchitecture is disrupted, and the amount and variety of non-collagenous proteins in bone is altered. Osteoporotic bones are more susceptible to fracture. Osteoporosis is defined by the World Health Organization (WHO) as either a bone mineral density 2.5 standard deviations below peak bone mass (20-year-old sex-matched healthy person average) as measured by DXA, or any fragility fracture. While treatment modalities are becoming available (such as the bisphosphonates), prevention is still considered the most important way to reduce fracture. Due to its hormonal component, more women, particularly after menopause, suffer from osteoporosis than men. In addition it may be caused by various hormonal conditions, smoking and medications (specifically glucocorticoids). Osteoporotic fractures are those that occur under slight amount of stresses that would not normally lead to fractures in nonosteoporotic people. Typical fractures occur in the vertebral column, hip and wrist.