Our bone remodels (i.e. formation and resorption) continuously at sites known as bone remodeling units. At these sites formation and resorption of bones is accomplished by osteoblasts and osteoclasts, respectively. This process of remodeling is controlled by hormonal and other factors. The bone mass continues to increase till the age of 30-35 years (peak bone mass). It remains stable for sometime and thereafter, bone loss starts gradually (after 40-50 years of age).


The normal balance between bone formation and bone loss maintains the bone mass. Whenever there is increased resorption and/or decreased formation of bone, osteoporosis may result. Therefore, peak bone mass which one attains during first three decades of life becomes very important in determining the future risk of developing osteoporosis, and its severity.