1.Genetics- if a parent had a hip fracture the risk doubles

2.Smoking and high amounts of alcohol (>3 units per day)

3.BMI <18.5 or previous anorexia

4.Some medications eg steroids or cancer treatments

5.Other medical conditions- eg rheumatoid arthritis, type 1 diabetes, chronic liver disease

6.Sedentary lifestyle

7.early menopause and premature ovarian insufficiency