Bone mineral density in children and adolescent girls with anorexia nervosa in Japan.

Background: The correlation between reduced bone mineral density (BMD) and the disease anorexia nervosa (AN) has long been established. The aim of the present study was to examine the relationship in more detail, particularly focusing on the increasing incidence of the disease occurring in adolescent patients.

Method: Twenty-four girls diagnosed with AN were enrolled in the study. All subjects ranged in age from 11.1 to 15.5 years, with an average age of 13.5 years. The BMD of lumbar spines and femoral necks were measured. All the values for BMD at admission were expressed as means +/- SD and patients with and without menarche were separately investigated.

Results: The average BMD of lumbar spines at the time of admission was -0.51 SD in total. However, the average BMD of patients without menarche was -1.28 SD, which was significantly lower than the -0.16 SD on average in patients with menarche. As a whole the BMD of femoral necks at admission tended to be lower than that of lumbar spines. Similarly, it was lower in patients without menarche (-1.7 SD on average) than in those with menarche (-0.77 SD on average).

Conclusions: BMD was lower in children and adolescent AN patients without menarche, and such a tendency was more significant at the femoral neck region. In child AN cases without menarche, the BMD, especially at the femoral neck, needs to be measured, and later recovery should be monitored closely over a long period.