Adolescent idiopathic scoliosis. Is low melatonin a cause?

Background. Although the cause of adolescent idiopathic scoliosis remains unclear, pinealectomy is followed by the development of scoliosis in chickens. Melatonin is the only hormone secreted by pineal gland. Objective. To assess serum melatonin levels in adolescents with idiopathic scoliosis. Methods. Serum melatonin was assayed once, at 12:00 hours, in each of 20 adolescents with idiopathic scoliosis and 10 age-matched siblings. In the patient group, mean age was 14.3 years and the mean Cobb angle was 54.5 degrees (range, 20 degrees-110 degrees). Mean age in the control group was 14 years. Results. Serum melatonin was significantly lower in the patients (mean, 7.7 pg/ml; range, 4 to 13 pg/ml) than in the controls (mean, 29.9 pg/ml; range, 19.3 to 46 pg/mL) (P < 0.00001). The 12 surgically treated patients had a mean melatonin level of 8.1 pg/mL, versus 7.2 pg/mL in the eight other patients (nonsignificant P and regression coefficient values). Serum melatonin was not significantly correlated with the Cobb's angle (regression coefficient, 0.18; P < 0.44). Conclusion. Our data suggest that serum melatonin levels may contribute to the pathogenesis of idiopathic scoliosis. (C) 2000 Editions scientifiques ei. medicales Elsevier SAS.