Osteoporose defineres som en knoglemineraltæthed (BMD, bone mineral density) i rygrad eller hofte, der er 2, 5 standarddeviationer under gennemsnitsværdien for en normal yngre population, eller som en tidligere skørhedsfraktur uanset BMD.
Osteoporosis is defined as bone mineral density (BMD) of the spine or hip 2.5 standard deviations below the mean value of a normal young population or as a previous fragility fracture, irrespective of bone mineral density.