['Data on bone mineral density (BMD) are lacking in adults with childhood onset (CO)-craniopharyngioma (CP) with hypothalamic damage from the tumor. In patients with CO GH deficiency, BMD increases during GH treatment.', 'The aims were to evaluate BMD in adults with CO-CPs on complete hormone replacement, including long-term GH and to evaluate the impact of hypothalamic damage on these measures.', 'BMD (dual-energy X-ray absorptiometry), markers of bone turn over, physical activity and calcium intake were assessed in 39 CO-CP adults (20 women), with a median age of 28 (17-57) years, in comparison with matched population controls.', 'Late puberty induction was recorded in both genders, but reduced androgen levels in females only. Only CP women had lower BMD (P=0.03) at L2-L4, and reduced Z-scores at femoral neck (P=0.004) and L2-L4 (P=0.004). Both genders had increased serum leptin levels (P=0.001), which significantly correlated negatively with BMD at L2-L4 (P=0.003; r=-0.5) and 45% of CP women had Z-score levels ≤-2.0 s.d. Furthermore, 75% of those with a Z-score ≤-2.0 s.d. had hypothalamic involvement by the tumor. Calcium intake (P=0.008) and physical activity (P=0.007) levels were reduced in CP men only. Levels of ostecalcin and crossLaps were increased in CP men only.'] Are hypothalamic involvement and insufficient sex steroid supplementation associated with low bone mineral density in women with childhood onset craniopharyngioma?