Distribution of ABO /Rh Blood Types Across Childhood Leukemia Subtypes: A Retrospective Cohort Study of 540 Pediatric Patients

ABSTRACT Importance Blood type has been proposed as a potential factor in cancer susceptibility; however, its role in childhood leukemia remains unclear. Prior studies have yielded conflicting results, and data from pediatric populations are limited. Objective This study examines whether ABO/Rh blood types are differentially distributed across acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML) subtypes in children. Design A retrospective cohort study was conducted that included 540 children aged 0–18 years diagnosed with leukemia between January 2010 and December 2023. Statistical associations were tested using χ 2 tests and ANOVA (R v4.1.3). Setting Database was collected from the national electronic health records from Clalit Health Services, Israel's largest healthcare provider. Participants A total of 540 pediatric oncologic patients were identified. Leukemia subtypes were distributed as acute lymphoblastic leukemia, acute myeloid leukemia, or chronic myeloid leukemia. Other data collected included blood type with its Rh type, age, sex, ethnicity, and disease outcome. Results No statistically significant association was found between blood type and leukemia subtypes ( χ 2 = 6.3, p = 0.600). This remained true after adjusting for age, sex, and ethnicity ( p values > 0.05). Survival status (alive/dead as of December 31, 2023) did not differ significantly by blood type ( p = 0.774), although O − patients showed the highest survival rate (94.1%) and AB + the lowest (82.9%). No differences were observed in blood type distribution by sex ( p = 0.892) or ethnicity ( p = 0.910). Subgroup analyses revealed slight numerical trends, such as a higher proportion of O + among AML cases (44.1%), but these lacked statistical power due to small sample sizes (AML n = 34, CML n = 10). Multivariable logistic regression showed no significant associations (all adjusted ORs 0.65–1.10; 95% CIs crossing 1.0). Conclusion In this cohort of pediatric leukemia patients, ABO/Rh blood types were not significantly associated with specific leukemia subtypes or survival outcomes. Because this study lacks a control group from the general population, it does not assess whether blood type influences the risk of developing leukemia; rather, it evaluates whether blood type is differentially distributed across leukemia subtypes among diagnosed cases. Our study contributes important evidence from a region with distinct blood type demographics and supports the need for future larger, multi‐center studies to explore subtle associations in rare subtypes and blood groups.