Bone status of children receiving anticonvulsant therapy

Bone mineral status was assessed by direct photon absorptiometry on 140 children and adolescent hospital outpatients receiving long-term anticonvulsant drug therapy and on 132 institutionalized mentally retarded subjects, 74 of whom were receiving anticonvulsant drugs. Serum calcium, phosphorus and alkaline phosphatase concentrations were determined for the hospital outpatients. Average deviations of bone mineral content (%BMC) ranged from 8.4-16.2% of normal values predicted from regression analysis. A trend toward increased demineralization was associated with length of anticonvulsant drug therapy. Mentally retarded subjects and hospital subjects with seizures accompanied by other serious disorders showed significantly greater osteopenia than hospital subjects with seizures alone. A lack of association of BMC with presence of anticonvulsant drug therapy in the mentally retarded population suggested that their low %BMC values were due to other factors related to the nature of the sample and the condition of institutionalization. Biochemical values showed a lack of association with osteopenia. A comparison of the present results on compact bone with results of others involving osteoid of trabecular bone suggests that anticonvulsant drug therapy affects these tissues differently and that the chemistry of the blood more closely reflects the osteoid proliferation of the trabecular bone rather than the changes related to the osteopenia of compact bone.