[Vitamin D status in children with renal diseases]

Assessment of vitamin D status in children with selected renal diseases based on serum 25OHD3 level taking into consideration type of kidney disease, vitamin D supplementation and season of the year.

Retrospective analysis of 127 children aged from 0.6 to 17.7 years, median 9.5 [24 with risk status of urolithiasis (RSU), 29 with urolithiasis, 15 with glomerulonephritis, 59 with idiopathic nephrotic syndrome (INS)] was performed. Serum concentrations of 25OHD3, 1,25(OH)2 D3, calcium, and phosphorus were measured. The correlation of 25OHD3 with the type of kidney disease, supplementation of vitamin D, seasons, gender, age, and the dose of glucocorticosteroids (in children with glomerulopathies) were analyzed.

In all children serum concentration of 25OHD3 from 4.3 to 72.6 ng/mL (median 21.1 ng/mL). The deficiency or insufficiency of vitamin D were observed in 55 (43.3%) analyzed children with kidney diseases. The deficiency or insufficiency of vitamin D were observed in 49.1% children with RSU and urolithiasis, and in 39.2% with glomerulonephritis and INS: in 36% children supplemented with vitamin D and 54% not supplemented (NS). In winter, 25OHD3 serum concentration was significantly higher in children supplemented with vitamin D compared to not supplemented [median 21.5 ng/mL vs 16.5 ng/mL (p<0.05)]. There were no significant differences in serum concentrations of 25OHD3 , 1,25(OH)2 D3 , calcium, phosphorus and calcium x phophorus product depending on type of kidney disease and gender. The significant negative correlation was found between 25OHD3 and patients' age (r=-0.26 p<0.01) and between calcium (r=0.31, p<0.05) and calcium x phosphorus in children supplemented with vitamin D (r=0.28, p<0.05).

Our results suggest the necessity to develop new strategies in vitamin D supplementation in children with kidney diseases. Futher studies shoud also be performed to evaluate their efficiency.