Mendelian randomization analysis reveals fresh fruit intake as a protective factor for urolithiasis

Abstract

Objective: Previous studies have proposed that food intakes are associated with the risk of urolithiasis. Here, we conducted a two-sample Mendelian randomization (MR) study to evaluate the causal effects of different food intakes on urolithiasis. Methods: Independent genetic variants associated with different food intakes at a genome-wide significant level were selected from summary-level statistics of genome-wide association studies from the UK Biobank. The association of these instrumental variables with urolithiasis was studied in a cohort from FinnGen Consortium. Results: Among the 15 studied food intake exposures, tea intake (odds ratio [OR] = 0.433, 95% confidence interval [CI] = 0.281–0.667, p value = 1.470 × 10–4) and fresh fruit intake (OR = 0.358, 95% CI = 0.185–0.694, p value = 0.002) were found to significantly reduce the risk of the calculus of kidney and ureter. The association remained consistent in the sensitivity analyses. After adjusting for the effects of vitamin D and vitamin C, fresh fruit intake remained the reverse causal association with the calculus of kidney and ureter. Conclusions: Genetically proxied fresh fruit intake is causally associated with a reduced risk of the calculus of kidney and ureter.