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.

Causal associations between 45 dietary intake habits and urolithiasis: insights from genetic studies

“…Tea intake, as the only reliable evidence of dietary habits in this study, yielded consistent results with previous research in significantly reducing the risk of urinary stone formation ( 9 , 26 ). A previous study has already established a relationship between fresh fruit consumption and kidney stones, which aligns with our findings ( 10 ). However, due to the continuous updates in the FinnGen database, we used the latest nephrolithiasis data that categorized the occurrence of urinary stones into upper and lower urinary tract.…”

“…Single nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for the exposure (e.g., various dietary habits) are used to estimate whether there is a causal relationship between the exposure and the outcome. Previous studies have utilized MR analysis to investigate the causal associations between coffee, tea, alcohol intake and frequency, fresh fruit consumption, and kidney stones ( 7 - 10 ). However, these studies only focused on a limited part of dietary habits and did not accurately classify different types of alcoholic beverages.…”