Background The correlation between body composition changes, osteopenia and alterations of leptin, Insulin-like-Growth Factor-1(IGF-1) and cortisol levels has been previously found in patients with anorexia nervosa (AN).

Objective The aim of this study was to investigate the relationship between bone formation (osteocalcin-OC) and bone resorption markers (BetaCrossLaps-BCL) and changes in bone mineral density (BMD), body mass index (BMI), body fat percentage (BF%), leptin, IGF-1 and cortisol levels.

Methods BMI, spinal Z-score (DXA), BF% and leptin, IGF-1, OC, BCL, cortisol levels were measured in 2 groups of girls: AN (n = 20, age 17.2 ± 0.3 years, amenorrhea duration 21.2 ± 0.4 months) and normal weight (n = 20, age 17.5 ± 0.2 years).

Results BMI (14.2 ± 0.86 vs 20.4 ± 0.86, t = -22.77, p = 0.0009), BF%(5.0 ± 1.5 vs 22.9 ± 2.7, t = -25.79, p = 0.0001), Z score (10.5 vs 30.5, Z = -5.41, p = 0.0006) and levels of IGF-1(308.1 ± 42.6 vs 538 ± 21.6; t = -9.75, p = 0.0007), leptin (10.5 vs 30.5, Z = -5.41, p = 0.0006) and OC (16.0 ± 3.49 vs 37.2 ± 5.34, t = -14.84, p = 0.0002) were significantly lower in AN group while levels of cortisol (713 ± 69.1 vs 451 ± 15.9; t = 11.82, p = 0.0003) and BCL (28.1 vs 12.9, Z = -4.1, p = 0.0004) were higher. In AN group we found: positive correlation between OC and BMI (r = 0.984, p = 0.0008), BF% (r = 0.983, p = 0,0008), Z score (r = 0.967, p = 0.0004), leptin (r = 0.985, p = 0.0001) and IGF-1 levels (r = 0.937, p = 0.0006); negative correlation between OC and cortisol (r = -0.982, p = 0.0005); negative correlation between BCL and BMI (r = -0.764, p = 0.0009), BF% (r = -0.724, p = 0.0001), Z score (r = -0.835, p = 0.0002), leptin (r = -0.777, p = 0.0004) and IGF-1 (r = -0.766, p = 0.0008) and positive correlation between BCL and cortisol (r = 0.815, p = 0.0001).

Conclusion Adolescents with AN have significantly altered body composition, impairment of leptin, IGF-1 and cortisol secretion, alterations in bone turnover and severe osteopenia. There is a correlation between bone turnover markers and Z-score, BMI and BF% in patients with AN. We found a significant relationship between leptin, IGF-1 and cortisol levels and bone turnover markers in AN patients.