Vitamin D status of ambulatory and nonambulatory mentally retarded children with and without carbamazepine treatment.

The subjects consisted of four groups: group 1 nonambulatory patients receiving carbamazepine; group 2 ambulatory patients receiving carbamazepine; group 3 nonambulatory patients receiving no drug, and group 4 ambulatory patients receiving no drugs. The serum 25-hydroxyvitamin D (25-OH-D) concentration was significantly lower in group 1 than in all other groups. There was no difference between the groups as regards the serum 1,25-dihydroxyvitamin D or 24,25-dihydroxyvitamin D concentration. Carbamazepine treatment lowers the serum 25-OH-D concentration, and inactivity which leads to a lower degree of time spent out-of-doors and thus a low exposure to sunlight still decreases the concentration. In this study a low dietary vitamin D intake probably was an aggravating factor.