Rickets in Nigerian children: response to calcium supplementation

This study determined the effect of calcium supplementation in 10 Nigerian children with rickets. Serum samples and 24-hour urine specimens were obtained from the 10 children and their corresponding controls which would serve as baseline. Following the collection of samples the rachitic subjects started on calcium supplements (1000 mg/day elemental calcium divided into two doses of TUMS chewable calcium carbonate tablets). Supplementation was continued for 12 weeks. Serum and urine collections were repeated after 24 hours 7 days 4 weeks and 12 weeks of calcium therapy. An estimate of their usual calcium and phosphorous intakes was obtained and serum calcium and vitamin D measurements were monitored during the course of calcium supplementation. The rachitic children and controls had calcium intakes well below the recommended daily allowance of 800 mg/day for children. The mean serum calcium concentration for the rachitic subjects was at the lower end of the reference range for children (8.7 mg/dl) and 7 rachitic children had serum calcium level below this value. 24 hours after the first calcium administration calcium level for those seven children increased. The mean serum phosphorous concentration of the rachitic children remained significantly low throughout the course of the study. Based on the results it is concluded that rickets in Nigeria may have more than one cause depending on geographic and ethnic factors. Nine out of 10 subjects showed radiographic evidence of healing after following the supplementation regimen for 3 months. The biochemical data indicated a multifactorial etiology pointing to a possible defect in the synthesis of 25-hydroxyvitamin D.