Remember, if the building crew does not have building materials, it cannot do its job. Calcium is the building block for bone and if the body does not have enough the bone will suffer. In fact, the body needs to maintain a steady level of calcium in the blood stream and if it is not receiving enough through its diet, it will pull it out of the bone. There are factors outside your control as well as within your control. The factors you cannot control are your gender, race and ethnic background.
Women are at greater risk than men.
Caucasian and Asian women are at greater risk than Black women. A family history of osteoporosis increases your risk. Older age and being post menopausal contributes to your risk. Lastly, if you have had a fracture as an adult that might suggest your bones never reached maximal density. Factors within your control include smoking and alcohol use.