Osteoporosis as defined by the World Health Organization (WHO) is having a bone density of 2.5 times or more standard deviations below the average young adult peak bone mass. In more general terms, to have osteoporosis means that the density of bone is decreased which makes bone weaker and more prone to fractures. In severe osteoporosis, a bone may break even while performing normal activities of daily living rather than as the result of some trauma.
Eating disorders increase risk of osteoporosis
Having an eating disorder in which body weight is lower than normal increases the risk of developing osteoporosis and subsequent bone fractures. Anorexia Nervosa, specifically, is one risk factor for developing osteoporosis though any eating disorder that causes an insufficient intake of calcium and vitamin D may also be risk factors.
Women who experience amenorrhea either as a result from low body weight or excessive exercise are also at increased risk for bone loss resulting in osteoporosis. Osteoporosis secondary to eating disorders occurs because both bone resorption is increased in order to maintain blood electrolyte levels and bone formation is slowed due to low estrogen levels and hypgonadism.
Men with eating disorders are also at an increased risk for developing osteoporosis. In one study, among 70 men admitted to an eating disorder clinic, 26% were found to have osteoporosis of the lumbar spine. Although this percentage is lower than found in female counterparts, the osteoporosis found in males is often more severe than that encountered in females.
Factors that increase risk of osteoporosis
Factors that increase the likelihood that a person with an eating disorder will develop osteoporosis include decreased calcium, fat, and vitamin D intake, a low body mass index, high cortisol levels in the blood, and increased length of illness duration.
Treatment for osteoporosis secondary to eating disorders includes first and foremost achieving a proper body weight. In addition, calcium and vitamin D supplementation may be necessary. Moderate weight bearing exercise may be helpful as well as a class of drugs called bisphosphonates which help rebuild bone.