Data Sheet 1_Causal association of peripheral immune cell counts with risk of prostate cancer: insights from bidirectional Mendelian randomization.docx

ObjectivesThis study aimed to examine the causal relationships between peripheral immune cell counts and prostate cancer, adhering to Mendelian Randomization reporting guidelines for transparency and reproducibility.
MethodsIn this study, bidirectional Mendelian randomization (MR) analysis, which includes MR-Egger, weighted median, weighted mode, and inverse variance weighted (IVW) approaches, was utilized to evaluate the bidirectional causal relationship between peripheral immune cell counts and the risk of PCa.
ResultsThe primary analysis using the IVW method suggests a potential causal association between basophil counts and the risk of prostate cancer (PCa), with an odds ratio (OR) of 1.111 and a 95% confidence interval (CI) of 1.011-1.222 (P = 0.028). Conversely, non-causal associations have been observed between other peripheral immune cell types, such as white blood cells, neutrophils, lymphocytes, eosinophils, or monocytes, and the incidence of PCa (P values > 0.05). Furthermore, although reverse analysis indicated a causal link between PCa and the counts of leukocytes and neutrophils (OR = 1.013; 95% CI = 1.002–1.225; P = 0.018 and OR = 1.013; 95% CI = 1.002–1.025; P = 0.019), no causal association was detected between PCa and basophil count (P value > 0.050).
ConclusionThis study suggests a potential bidirectional link between peripheral immune cells and prostate cancer, but inconsistencies in Mendelian Randomization methods mean these findings are preliminary and require further investigation.