Vitamin D, Hypercalciuria and Kidney Stones

Area of Science:

• Nephrology
• Endocrinology
• Nutritional Science

Background:

• Nephrolithiasis (kidney stones) risk is increasing, often linked to hypercalciuria (high urinary calcium).
• Vitamin D metabolites, like calcitriol, enhance calcium absorption, potentially increasing urinary calcium and stone formation.
• Historically, low evidence linked 25-hydroxyvitamin D levels to kidney stones, despite high calcitriol in stone formers.

Purpose of the Study:

• To investigate the association between vitamin D supplementation and kidney stone formation.
• To explore the impact of vitamin D on urinary calcium excretion in stone formers.
• To identify potential predisposition factors for vitamin D-induced nephrolithiasis.

Main Methods:

• Review of prospective studies on vitamin D and calcium supplements.
• Analysis of epidemiological data correlating 25-hydroxyvitamin D levels with kidney stones.
• Examination of studies measuring urinary calcium excretion after vitamin D supplementation.

Main Results:

• Increased kidney stone episodes observed with vitamin D (alone or with calcium) in some studies.
• Association found between high 25-hydroxyvitamin D levels and kidney stone formation in specific patient groups.
• Urinary calcium excretion increased with vitamin D supplements in certain kidney stone formers.

Conclusions:

• Vitamin D supplementation may predispose certain individuals to hypercalciuria and kidney stone formation.
• The link between vitamin D, calcium metabolism, and nephrolithiasis warrants further investigation.
• Clinical guidelines for vitamin D prescription should consider potential risks for kidney stone development.