Serum concentrations of 25-hydroxyvitamin D in Florida children: effect of anticonvulsant drugs

Abstract

The mean serum concentration of 25-hydroxyvitamin D (25OHD), determined by nonchromatographic radioassay, was significantly lower (P less than .02) in Florida children with epilepsy treated with anticonvulsant drugs (34.4 +/- 11.3 [SD] ng/ml) than in normal subjects (40.9 +/- 14.3), despite exposure of both groups to sunlight throughout the year. In 12% of children treated with anticonvulsant drugs, the 25OHD level was below the lowest value recorded in the control group. The mean serum concentration of 25OHD in normal Philadelphia children (27.5 +/- 9.1 ng/ml) was significantly less than in either group of Florida subjects. Annual monitoring of calcium homeostasis and vitamin D status is indicated in Southern children receiving anticonvulsant drugs, but routine vitamin D supplementation of such patients is unnecessary.