Platelet Indices and the Causal Relationship with Myeloid Leukemia: a Mendelian Randomization Study with Dual Samples

Platelets are correlated with myeloid leukemia (ML), but to date, there have been no studies confirming the causal relationship between them.

Platelet count (PLT), mean platelet volume (MPV), plateletcrit (PCT), and platelet distribution width (PDW) data were obtained from the GWAS catalog database as exposure factors. Acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) data were obtained from the FinnGen database as outcome indicators. The causal relationship between exposure and outcome was explored using the inverse variance weighted, MR-Egger, weighted median, and simple mode methods of dual-sample Mendelian randomization (MR). The stability and reliability of the results were assessed using Cochran's test, MR-Egger regression, and MR-PRESSO methods.

An elevated PCT is positively associated with the risk of CML [ORMR-Egger = 2.591, 95% CI (1.089 - 6.166), p = 0.032; ORSimple mode = 9.873, 95% CI (1.112 - 87.646), p = 0.040]. There was no evidence of heterogeneity or plei-otropy at the gene level. However, there were no causal associations between other indices and CML, and none of the four platelet indices were causally associated with AML.

An increase in PCT significantly increases the risk of developing CML, making it a candidate biomarker for clinical screening of CML.