There is an online tool called FRAX. This takes the result of your DEXA scan which is called your t-score and factors in additional risks including smoking, family history, previous fractures, alcohol intake, and rheumatoid arthritis. It's a bit complicated as it requests the type of scanner used. Physicians can use it to decide whether to advise drug treatment in borderline cases. It provides a per cent chance of having a fracture in the next ten years. The higher the percentage, the more likely you are to benefit from treatment
It can be difficult to decide whether to use medication in addition to Calcium, Vitamin D and weight bearing exercise.
http://www.shef.ac.uk/FRAX/tool.aspx?country=9