Aetiology of nutritional rickets in rural Bangladeshi children.

objectivesA high prevalence of rickets of unknown aetiology has been reported in Chakaria, Bangladesh. Classically, rickets is caused by vitamin D deficiency but increasing evidence from Africa and Asia points towards other nutritional deficiencies or excessive exposure to some metals. The aim of this study was to investigate the aetiology of rickets in rural Bangladeshi children.

methods64 cases with rickets-like deformities were recruited at first presentation together with age-sex-village matched controls. Data and sample acquisition included anthropometry, radiographs, fasted plasma and urinary samples, 24 h weighed dietary intake together with a 24 h urine collection, and

resultsOne child had active rickets and frank hypovitaminosis D (F, n = 1) and one had deformities with radiological features of Blount disease (M, n = 1). The remaining cases were grouped into those with active rickets, defined as a radiographic Thacher score ≥1.5 (Group A, n = 24, 12M, 12F) and rickets-like bone deformities but not active rickets (Group B, n = 38, 28M, 10F). All children had a low dietary calcium intake, but this was lower in Group A than their controls (mean (SD): 156 (80) versus 323 (249) mg/day, p = 0.005). Plasma 25-hydroxyvitamin D (25OHD) was lower in Group A compared to controls; 63% of Group A and 8% of controls had a concentration <25 nmol/L (p ≤ 0.0001). There was, however, no evidence of differences in skin sunshine exposure. Group A had lower plasma calcium and phosphate and higher 1,25-dihydroxyvitamin D (1,25(OH)

conclusionNutritional rickets in this region is likely to be predominantly due to low calcium intake in the context of poor vitamin D status and exposure to environmental metals, but not H. pylori infection, anaemia or iron deficiency.