Osteopaenia of the lumbar spine and femoral neck in anorexia nervosa.

The bone density in the spine, femoral neck and radius in 31 outpatients with anorexia nervosa (AN) was measured by photon absorptiometry and compared with 31 age matched controls. In all bone sites measured the patients with anorexia nervosa had reduced bone mineral density (spine- control 0.91 + .10 gHA/cm2, AN 0.75 + .09 gHA/cm2; femur- control 0.87 + .09 gHA/cm2, AN 0.67 + .07 gHA/cm2; radius-control 0.41 + .04 gHA/cm2, AN 0.38 + 0.9 gHA/cm2). The mean difference between the groups was greatest in the femoral neck at 0.21 gHA/cm2 (95% CI 0.18-.024 p less than 0.001) and least at the radius 0.04 gHA/cm2 (95% CI 0.02-0.06, p less than 0.05), the lumbar spine was intermediate with a mean difference of 0.16 gHA/cm2 (95% CI 0.12-0.2 p less than 0.001). Femoral and spinal bone mineral density was positively correlated with body mass and negatively correlated with duration of amenorrhoea. Three of these patients had vertebral crush fractures which suggests that this diminution in bone density is of clinical significance.