A pioneering two-sample Mendelian randomization (MR) analysis has uncovered significant associations between specific dietary choices and the risk of IgA nephropathy (IgAN), offering new insights into potential preventive strategies for this challenging kidney disease.
The comprehensive study, conducted by researchers at the Affiliated Hospital of Southwest Medical University in China, analyzed data from 477,784 participants, including 15,587 cases and 462,197 controls from the EBI database, examining 26 different dietary exposures categorized as protein, carbohydrates, plant-based diets, and beverages.
Key Protective Dietary Factors Identified
The research revealed several dietary elements associated with reduced IgAN risk. Cheese consumption showed a significant protective effect (OR: 0.626; 95% CI: 0.492-0.798; P=0.0001559), along with cereal intake (OR: 0.652; 95% CI: 0.439-0.967; P=0.0334126) and sushi consumption (OR: 0.145; 95% CI: 0.021-0.997; P=0.049685).
Alcohol Consumption as Risk Factor
Notably, the study identified frequent alcohol intake as a significant risk factor for IgAN development (OR: 1.267; 95% CI: 1.100-1.460; P=0.0010295). This finding remained consistent across multiple statistical validation methods, including MR-Egger regression and weighted median analyses.
Study Methodology and Validation
The research team employed robust methodological approaches, utilizing instrumental variables that met three critical assumptions: strong relation to dietary intake, independence from confounding factors, and absence of direct correlation with IgAN through non-dietary pathways. The inverse variance weighted (IVW) method served as the primary analytical approach, complemented by multiple sensitivity analyses.
Clinical Context and Implications
"The drug treatment of IgAN relies on renin-angiotensin-aldosterone system inhibitors, glucocorticoids and immunosuppressants. However, some patients experience severe adverse drug reactions and poor sensitivity," explains Dr. Longyang Jiang, the study's lead researcher. This understanding underscores the importance of identifying preventive strategies through dietary modification.
Study Limitations and Future Directions
While groundbreaking, the study acknowledges several limitations. The participant pool predominantly represented European populations, potentially limiting generalizability to other ethnic groups. Additionally, the research couldn't evaluate nonlinear associations between dietary exposures and IgAN risk, and some dietary factors remained unassessed.
This research marks the first use of Mendelian randomization to explore causal relationships between dietary patterns and IgAN risk, opening new avenues for preventive medicine in nephrology. The findings suggest that dietary modifications, particularly regarding alcohol consumption and the inclusion of protective foods, could play a crucial role in IgAN prevention strategies.
