Osteoporosis is a skeletal disorder characterized by low bone
mass and microarchitectural deterioration of bone tissue, with a
consequent increase in bone fragility [1 ]. It is the commonest
bone disorder in Western populations, and an important public
health issue because of the potentially devastating consequences
of fragility fracture [2 ]. Hip fractures are the most important
consequence of osteoporosis; they require hospital admission and
are associated with an excess mortality of 10–20% in the first
year after the fracture [3 ]. In white women the one in six
lifetime risk of hip fracture is greater than the one in nine
risk of developing breast cancer [4 ]. The annual cost of all
osteoporotic fractures to the United States has been estimated
as $20 billion and to the European Union as $30 billion [5
Osteoporotic fracture is a result of a combination of an injury
generating a given force, and bone strength weak enough to
fracture at that force. An established measure of bone strength
is bone mass, which