Bone Abstracts

Anorexia nervosa (AN) is an eating disorder characterized by severe undernutrition. Osteopenia is a frequent, often persistent complication of anorexia nervosa (AN) in adolescent girls and occurs during a critical time of bone development. To determine the impact of chronic undernutrition on bone mineral accrual we measured bone mineral density by dual energy x-ray absorptiometry, bone metabolism markers and leptin levels in AN patients (n=19, age 22.67±1.9 years, BMI 14.13±0.39 kg/m²), with persisting amenorrhea in contrast to age matched healthy female controls (n=10, age 23.33±3.01 years, BMI 20.10±0.87 kg/m²).

We assessed: bone markers (serum osteocalcin, C-telopeptide of type I collagen -sCTX, vitamin D and PTH), and serum leptin levels measured by Linco Kit radioimmunoassay. BMD was measured by DXA at the lumbar spine. Data were presented as mean±S.E.M.

We showed that there was a significant change in AN patients to healthy controls in vitamin D levels (38.62±6.81 vs 77.50±13.61 nmol/l, P<0.01), leptin levels (4.1±0.49 vs 9.7±2.1 ng/ml, P<0.01) and z-score (−2.56±1.2 vs 0.67±0.2, P<0.01).

In both groups we found positive correlation between leptin and osteocalcin (Pearsons P<0.05), leptin and z-score (P<0.08), but negative correlation between leptin and CTx (P<0.06), and leptin and vitamin D levels (P<0.05), In AN patients, osteocalcin positively correlated with PTH (Pearsons, r=0.667, P<0.05), and with vitamin D (r=0.717, P<0.03), but negatively with t-score (r=−1.00, P=0.00).

Our findings confirmed deleterious effects of undernutrition and on bone metabolism and failure to achieve peak bone mass in AN patients. Consequences of low body weight in AN are hipoleptinemia, which is imbalance of bone turnover (high bone resorption and low bone formation), associated with low BMD.