Near normalisation of lumbar spine bone density in young women with osteopenia recovered from adolescent onset anorexia nervosa: a longitudinal study.

To investigate the effect of the progression of adolescent onset anorexia nervosa (AN) on bone parameters we followed two cohorts (Disease cohort and recovered cohort) of adolescents for a total of 5.2 years. In the 'Disease' cohort (n = 18), lumbar spine bone density (BMD) was reduced by 0.6 SD after 0.8 years of disease and was reduced a further 1.0 SD after a total 2.5 years of disease (p < 0.001). At the third lumbar vertebra there was bone loss (-3.7%, p < 0.05) resulting in reduced volumetric BMD (-5.1%, p < 0.08). In the 'recovered' cohort, lumbar spine BMD was reduced by 1.9 SD after 1.7 years of disease, and increased by 1.5 SD after 2.7 years of recovery (p < 0.001). At the third lumbar vertebra there was an increase in bone mass (20.5%, p < 0.001) and bone volume (14.1%, p < 0.001), resulting in increased volumetric BMD (6.3%, p < 0.08). Normalisation of lumbar spine BMD may be achieved in patients with adolescent onset AN when the successful recovery of body weight is combined with the return of regular menses.