Association between Circulating Vitamin D Level and Urolithiasis: A Systematic Review and Meta-Analysis

Area of Science:

• Nephrology
• Endocrinology
• Nutritional Science

Background:

• Conflicting results exist regarding vitamin D levels in nephrolithiasis.
• Observational studies have investigated serum/plasma 1,25 dihydroxyvitamin D₃ (1,25(OH)₂D) and 25 hydroxyvitamin D₃ (25(OH)D) in stone formers versus controls.

Purpose of the Study:

• To systematically analyze and synthesize existing evidence on vitamin D metabolite levels in individuals with and without kidney stones.
• To clarify the association between 1,25(OH)₂D and 25(OH)D and different types of nephrolithiasis.

Main Methods:

• A comprehensive meta-analysis was conducted, systematically searching multiple databases (PubMed, Web of Science, Cochrane Library, CNKI, Wanfang).
• Thirty-two observational studies involving 23,228 participants were included in the analysis.
• Statistical methods, including weighted mean difference (WMD) and confidence intervals (CI), were used to compare vitamin D levels.

Main Results:

• Calcium stone formers showed significantly higher 1,25(OH)₂D levels compared to non-stone formers.
• No significant difference in 25(OH)D levels was observed between calcium stone formers and non-stone formers.
• Hypercalciuria stone formers exhibited increased 1,25(OH)₂D and markedly higher 25(OH)D levels compared to controls and normocalciuria stone formers.

Conclusions:

• Elevated circulating 1,25(OH)₂D is associated with urinary stones.
• Higher circulating 25(OH)D levels are significantly linked to hypercalciuria urolithiasis.
• Further research is warranted to fully elucidate the role of vitamin D in the pathogenesis of kidney stones.