Serum 25-Hydroxycalciferol Levels and Bone Mass in Children on Chronic Anticonvulsant Therapy

Abstract

Fifty-six children with epilepsy receiving chronic therapy with phenobarbital or diphenylhydantoin or both and 51 controls were studied to determine the effects of anticonvulsant therapy on mineral, vitamin D and bone metabolism. Combination therapy was associated with the greatest decreases in serum calcium (9.72 ± 0.06 vs. 10.40 ± 0.05 mg per 100 ml in controls; p < 0.001), serum 25-hydroxycalciferol (13.1 ± 1.0 vs. 23.6 ± 0.9 ng per milliliter in controls; p < 0.001), and bone mass by photon absorptiometry (90.5 ± 1.6 vs. 100.7 ± 1.0 per cent in controls; p < 0.001). Serum bone and liver alkaline phosphatase isoenzyme activity was increased in both treatment groups. Serum calcium concentration correlated with serum 25-hydroxycholecalciferol levels in both the single and combined drug groups. Serum 25-hydroxycholecalciferol correlated with vitamin D intake in all groups, but mean levels of the metabolite were lower for any given level of vitamin D intake in treated patients. Thus, vitamin D supplementation appears indicated in children on chronic anticonvulsant therapy. (N Engl J Med 292:550–554, 1975)