Vitamin D status is insufficient in the majority of children at diagnosis of nephrotic syndrome

INTRODUCTION: Children with nephrotic syndrome (NS) are treated for at least 12 weeks with high doses of prednisolone, which may be harmful to the bones. Vitamin D deficiency is also harmful to the bones.

METHODS: This was a prospective study of consecutive children with first episode of NS at the time of their diagnosis before treatment with glucocorticoids. The following plasma levels were measured: 25-hydroxy-vitamin-D (25(OH)D), albumin, ionised calcium, phosphate, parathyroid hormone (PTH), alkaline phosphatase and creatinine. The glomerular filtration rate (GFR) was estimated from the Schwartz formula, and only patients with normal values were included.

RESULTS: A total of 14 children were examined, 13 (93%) had 25(OH)D deficiency including 12 (86%) with moderate or severe vitamin D deficiency. The plasma 25(OH)D was positively associated with plasma albumin (p = 0.031) and negatively with PTH (p = 0.003), phosphate (p = 0.016) and body mass index percentile (p = 0.022). PTH was negatively associated with albumin (p = 0.019) and the estimated GFR (p = 0.007), and positively associated with phosphate (p = 0.008), 24-h urine protein/m2 (p = 0.018) and systolic blood pressure percentiles (p = 0.048).

CONCLUSION: The vitamin D status was insufficient in 93% of the patients. We suggest that vitamin D status in children with NS be measured routinely at the time of diagnosis so that an individual treatment strategy for vitamin D defi-ciency can be given. Further studies are needed to evaluate the effect of such treatment.

FUNDING: not relevant.

TRIAL REGISTRATION: not relevant.