Case-control study of factors associated with nutritional rickets in Nigerian children

Abstract Objective: Because the causes of nutritional rickets in tropical countries are poorly understood, we conducted a case-control study to determine factors associated with rickets in Nigerian children. Study design: We compared 123 Nigerian children who had rickets with matched control subjects. Dietary, demographic, anthropometric, and biochemical data were collected to assess factors related to calcium and vitamin D status, which might predispose children to rickets. Results: Mean (± SD) daily dietary calcium intake was low in both children with rickets and control children (217 ± 88 mg and 214 ± 77 mg, respectively; P =.64). Children with rickets had a greater proportion of first-degree relatives with a history of rickets (14.6% vs 3.1%; P P =.041), and a delayed age of walking (14 vs 12 months; P P Conclusions: Vitamin D deficiency appears unlikely to be the primary etiologic factor of rickets in African children. Moreover, low dietary calcium intake alone does not account for rickets. Insufficient dietary calcium probably interacts with genetic, hormonal, and other nutritional factors to cause rickets in susceptible children. (J Pediatr 2000;137:367-73)