312 Bone Mineral Density in the Lumbar Spine in Anorexic Girls

Abstract

Background and aims: Cross sectional study of 161 female anorexic adolescents (14.9 ± 4.2 year). Methods: 57/161 anorexic girls received a dual X-ray absorptiometry (DEXA) to measure their bone density. DEXA scans were performed using Hologic, Inc. (QDR 2000/1500) in 19/57 patients and Lunar Prodigy (GE, Lunar, Madison, WI) in 18 patients. We measured the BMD (bone mineral density) total body (g/cm2), BMC (bone mineral content) total body (g) and BMD lumbar spine L1-L4 (g/cm2). The values of the hologic DEXA scan were standardised and calculated for the lunar values using the conversion formula of Hui et al. for the lumbar spine L1-L4, and compared with the reference values for age and gender of Van der Sluis et al. Results: Z-scores were calculated (Z-score:Patient's BMD - Expected BMD (Van der Sluis)/SD). We found in 14/57 patients a Z-score of the lumbar spine of ≥ -2, 17/57 girlshad a Z-score between ≥ -1 and ≥ -2 and in 26/57 patients the Z-score was ≥ -1. We divided the anorexic DEXA-scan group in 2 subgroups. Group 1 (n=23) were the girls with primary amenorrhea and group (n=28) were the girls with secondary amenorrhea. In 6/57 patients we had no information of the menstrual cycle. Conclusions: The anorexic girls with primary amenorhea were younger, had a lower BMI and significant lower BMD (L1-L4) and Z-scores BMD. There were no significant differences in weight loss, ghrelin and leptin. Finally we could say that an anorexia nervosa status in girls with primary amenorrhea has a severe prognosis for the bone mineral density.