Depending on the cause, the disease is divided into primary and secondary osteoporosis. The primary form covers about 95 percent of cases and develops primarily due to an estrogen deficiency, i.e. during the menopause in women. In addition, primary osteoporosis occurs in both men and women due to the natural aging process of bones, calcium, vitamin D and lack of movement. Secondary osteoporosis is very rare and can occur in both genders. It is usually a consequence of certain diseases or drug therapies that have a negative effect on bone metabolism.