Osteoporosis is a condition in which bones become less dense and fractures occur more easily. Osteoporosis is most often caused by gradual bone thinning that occurs with age. However, other diseases may cause osteoporosis. Cortisol is a hormone that helps the body withstand stress. Diseases that increase cortisol levels in the blood typically cause many symptoms and signs, including osteoporosis. Researchers have found that some apparently healthy people have high blood cortisol levels. Osteoporosis could be a sign of high cortisol levels in these people.