Steroid therapy can cause thinning of the bones (osteopenia and osteoporosis), and increase the risk of bone fractures. At the beginning or before your steroid therapy, many patients will be asked to have a bone density test, especially if the steroid dose is high. If density is low, the bone density study It will be repeated in the future to assess the effectiveness of measures you will be using to prevent bone loss. Preventative strategies are important: a person can lose 10% to 20% bone mass within the first six months of corticosteroid therapy.