Effect of antiepileptic drugs on bone mineral density in children between ages 6 and 12 years

We assessed the effects of sodium valproate and carbamazepine monotherapy o n bone mineral density (BMD) in children. BMD at the lumbar vertebrae (L-1- L-4) and radius-ulna was measured by the dual-energy x-ray absorptiometry ( DEXA) method in 19 children (9 girls, 10 boys) with uncomplicated epilepsy and in 57 healthy children (28 girls, 29 boys), between the ages of 6 and 1 2 years. The study patients had been receiving either sodium valproate (n = 13) or carbamazepine (n = 6) monotherapy for more than 6 months. There wer e no significant differences between the control and study patients in age, height, weight, physical activity, or of serum concentrations of calcium, phosphate, and transaminases (aspartate aminotransferase, alanine aminotran sferase). However, the serum alkaline phosphatase concentration was greater in the patient group as compared with the control group. BMD values were l ower in girl patients (L-1-L-4; 0.497 +/- 0.08 vs 0.566 +/- 0.07 g/cm(2), p < 0.05), but not in boys (0.534 +/- 0.06 vs 0.530 +/- 0.08 g/cm(2)). While BMD reduction was 8% in valproate therapy (midregion of radius-ulna; 0.287 +/- 0.03 vs 0.312 +/- 0.04 g/cm(2), p < 0.04), it was reduced only 4.5% in the carbamazepine-treated group (0.298 +/- 0.01 vs 0.312 +/- 0.04 g/cm(2), statistically not significant), although the mean durations of monotherapy with valproate (1.8 +/- 0.7 years) and carbamazepine (1.7 +/- 0.8 years) w ere similar. Thus decreased bone mineralization was observed in children wi th epilepsy, treated with sodium valproate even though treatment was for a rather short time.