Dietary factors causally affect the risk of kidney cancer: a two-sample Mendelian randomization study

Previous observational studies have indicated potential associations between certain dietary factors and the incidence of kidney cancer. However, the causal relationship between these elements remains unknown. This study is aimed to investigate the causal relationship between dietary factors and the incidence of kidney cancer through Mendelian randomization (MR) analysis.

The study utilized genome-wide association study (GWAS) summary data from the GWAS Catalog and the IEU Open GWAS project databases. The exposure factors included consumption of dessert (n = 20,622), fruit (n = 421,155), alcohol (n = 462,346), and salt (n = 323,995). The outcomes were based on GWAS data for kidney cancer (cases = 1,103, controls = 455,245). Three MR methods, including Inverse Variance Weighted (IVW), MR-Egger, and Weighted Median, were used in the study, with IVW serving as the primary method. Sensitivity analyses such as the MR-Egger intercept test, Cochran's Q test, and leave-one-out analysis were performed to detect heterogeneity and pleiotropy.

The IVW method demonstrated a significant causal relationship between frequent alcohol consumption (OR = 1.61, 95% CI: 1.02-2.54, P = 0.040) and kidney cancer. In contrast, no causal associations were found with the consumption of alcohol (OR = 1.12, 95% CI: 0.91-1.37, P = 0.280), dessert (OR = 1.23, 95% CI: 0.71-2.12, P = 0.465), fruit (OR = 1.33, 95% CI: 0.59-3.00, P = 0.494) or salt (OR = 0.01, 95% CI: 0.00-1.49, P = 0.073). The sensitivity analyses did not reveal any evidence of pleiotropy.

This MR study suggests that frequent alcohol consumption can increase the risk of kidney cancer, whereas no significant causal relationships were detected between the consumption of dessert, fruit or salt and the risk of kidney cancer.