Aims: The purpose of this study was to assess the vitamin D status of children with renal disease attending the outpatient clinics of our tertiary nephrology centre, allowing us to determine the prevalence of vitamin D deficiency and study its relationship with glomerular filtration rate and serum PTH concentration.
Methods: 90 boys and 53 girls: 99 White Caucasians, 38 of South Asian origin and 6 of other ethnic groups were enrolled into the study. 18 were on dialysis (15 peritoneal dialysis and 3 haemodialysis) and 61 had functioning renal transplants (19 with reduced GFR), 18 had chronic renal failure and 46 had a variety of renal disorders with normal renal function. Serum/plasma concentrations of 25(OH)D, 1,25(OH)2D, PTH, creatinine, calcium, phosphate and alkaline phosphatase were measured. Patients with serum 25(OH)D concentrations less than 25 nmol/l were considered to be deficient and 25-50 nmol/l as insufficient.
Results: 26% of all patients were 25(OH)D deficient and a further 32% insufficient. The prevalence in South Asians was higher (87% deficient/insufficient) than in White Caucasians (46% deficient/insufficient, p<0.0001). In children with reduced GFR who were not on dialysis 25(OH)D levels of less than 50 nmol/l was associated with a high PTH in 90% of cases compared to only 50% in those with normal vitamin D concentrations (p=0.013).
Conclusion: A high proportion of renal patients were vitamin D deficient/insufficient particularly children of South Asian origin. High PTH values in the setting of reduced GFR might be due to vitamin D deficiency and should lead to estimation of serum 25(OH)D concentration.