A comparison of calcium, vitamin D, or both for nutritional rickets in Nigerian children

Background Nutritional rickets remains prevalent in many tropical countries despite the fact that such countries have ample sunlight. Some postulate t hat a deficiency of dietary calcium, rather than vitamin D, is often respon sible for rickets after infancy. Methods We enrolled 123 Nigerian children (median age, 46 months) with rick ets in a randomized, double-blind, controlled trial of 24 weeks of treatmen t with vitamin D (600,000 U intramuscularly at enrollment and at 12 weeks), calcium (1000 mg daily), or a combination of vitamin D and calcium. We com pared the calcium intake of the children at enrollment with that of control children without rickets who were matched for sex, age, and weight. We mea sured serum calcium and alkaline phosphatase and used a 10-point radiograph ic score to assess the response to treatment at 24 weeks. Results The daily dietary calcium intake was low in the children with ricke ts and the control children (median, 203 mg and 196 mg, respectively; P=0.6 4). Treatment produced a smaller increase in the mean (+/-SD) serum calcium concentration in the vitamin D group (from 7.8+/-0.8 mg per deciliter [2.0 +/-0.2 mmol per liter] at base line to 8.3+/-0.7 mg per deciliter [2.1+/-0. 2 mmol per liter] at 24 weeks) than in the calcium group (from 7.5+/-0.8 mg per deciliter [1.9+/-0.2 mmol per liter] to 9.0+/-0.6 mg per deciliter [2. 2+/-0.2 mmol per liter], P<0.001) or the combination-therapy group (from 7. 7+/-1.0 mg per deciliter [1.9+/-0.25 mmol per liter] to 9.1+/-0.6 mg per de ciliter [2.3+/-0.2 mmol per liter], P<0.001). A greater proportion of child ren in the calcium and combination-therapy groups than in the vitamin D gro up reached the combined end point of a serum alkaline phosphatase concentra tion of 350 U per liter or less and radiographic evidence of nearly complet e healing of rickets (61 percent, 58 percent, and 19 percent, respectively; P<0.001). Conclusions Nigerian children with rickets have a low intake of calcium and have a better response to treatment with calcium alone or in combination w ith vitamin D than to treatment with vitamin D alone. (N Engl J Med 1999;34 1:563-8.) (C)1999, Massachusetts Medical Society.