High dose vitamin D therapy in relation to serum calcium levels and nephrolithiasis

摘要

Institute of Medicine, USA lias published their new recommendations for Vitamin D and Calcium intake in 2010. It carried caution about hypercalcemia and nephrolithiasis with high dose of Vitamin D. This retrospective research was conducted to assess the correlation between vitamin D intake and serum calcium level. Case records from 2008 to 2011 were retrieved to obtain relevant information. The serum 25 hydroxy vitamin D levels were correlated with serum calcium levels and the intake of vitamin D as D3. The history of any new nephrolithiasis was noted. SPSS-19 was used to analyze the data. ANOVA test was used to assess whether there was any significant difference in the mean level of calcium. There were a total of 121 vitamin D levels done in patients who had normal serum albumin level, kidney and liver functions. The levels of 25 hydroxy vitamin D, calcium and albumin were recorded along with the Vitamin D intake from all sources. All patients had a minimum intake of at least 1000 mg of calcium from all sources. None of the cases showed hypercalceruia (over 10.5 mg/dL). One case had a urinary bladder stone in a diverticulum. There was a steady increase in the mean serum calcium levels as the Vitamin D3 dosage increased from 1000 to 7000 IU per day. The correlation coefficient between Vitamin D intake and serum calcium level was statistically not significant. The serum calcium levels in relation to Vitamin D dosage was not statistically significant indicating that even 2000 to 7000 IU of Vitamin D3 intake daily for several months was safe. Vitamin D3 therapy in the range of 2000 to 7000 IU per day does not cause hypercalcemia in patients with intact kidney and liver functions. Hence the chances of nephrolithiasis are not higher in these dose ranges.