Association between dried fruit intake and kidney function: research from univariate and multivariate Mendelian...

Area of Science:

• Nephrology
• Nutritional Epidemiology
• Genetic Epidemiology

Background:

• Observational studies suggest a link between dried fruit consumption and kidney function.
• Limitations of previous studies include confounding factors and reverse causality.
• A Mendelian randomization approach is needed to establish causality.

Purpose of the Study:

• To investigate the potential causal relationship between dried fruit intake and kidney function markers.
• To assess the impact of dried fruit on blood urea nitrogen (BUN), creatinine (CR), uric acid (UA), and cystatin C (CysC).

Main Methods:

• A two-sample Mendelian randomization (MR) study was performed.
• Genome-wide association study (GWAS) data was utilized for large-scale genetic analysis.
• Inverse variance weighting (IVW), MR-Egger, and weighted median methods were employed for robust analysis.
• Multivariate Mendelian randomization (MVMR) was used to adjust for potential confounders like alcohol and smoking.

Main Results:

• Increased dried fruit intake was causally associated with lower levels of BUN, CR, UA, and CysC.
• No significant association was found with hematuria or microalbuminuria.
• The causal effect on BUN and CR diminished after accounting for alcohol consumption and smoking in MVMR analysis.
• The causal effect on UA and CysC weakened but remained significant after adjustment for alcohol and smoking.

Conclusions:

• Dried fruit intake may have a beneficial causal effect on kidney function markers, particularly in the absence of smoking and alcohol consumption.
• The observed association between dried fruit intake and kidney function is influenced by lifestyle factors such as alcohol and smoking.
• These findings suggest a potential dietary strategy for managing chronic kidney disease progression.