Association between ABO blood groups and major disease categories in a retrospective cohort of 1.7 million blood donors

Background: ABO blood groups have a certain correlation with the incidence of many diseases. We aimed to explore the association between ABO blood groups and the top 25 fatal diseases in China. Methods: We constructed a retrospective cohort of 1,704,333 blood donors to investigate the association between ABO blood groups and the top 25 fatal diseases among Chinese individuals. We summarised differences in disease patterns across blood groups using multivariate Cox proportional hazards regression models. Results: Among the enrolled participants, type A (HR = 1.07; 95% CI = 1.03-1.09, P = 0.004) and type B (HR = 1.06; 95% CI = 1.02-1.09, P = 0.045) donors were more likely to develop ischaemic heart disease (I20-25) than type O donors. Compared with type O, type A (HR = 1.10; 95% CI = 1.06-1.13, P < 0.00067) and B (HR = 1.12; 95% CI = 1.08-1.14, P < 0.00067) donors were found to have more likely to develop diabetes mellitus (E10-14) (significant after Bonferroni correction). Type AB (HR = 1.84; 95% CI = 1.40-2.13, P = 0.05) and B (HR = 1.44; 95% CI = 1.19-1.71, P = 0.036) were more likely to develop colorectal cancer (C18-C20).Type A (HR = 0.93; 95% CI = 0.90-0.96, P = 0.025) and type B (HR = 0.93; 95% CI = 0.88-0.96, P = 0.020) were less likely to develop influenza, pneumonia, and acute lower respiratory tract infections (J09-22). Mean hospital stay differed significantly among blood groups for C18-20 (P = 0.045) and I20-25 (P = 0.008). Conclusions: We found a significant correlation between ABO blood groups and the top 25 fatal diseases in China, including ischaemic heart disease, diabetes, and colorectal cancer among blood donors. The associations should be considered exploratory and require independent validation for the general population. Registration: China National Medical Research Register: MR-61-21-011750; Chinese Clinical Trial Registry: ChiCTR2200055983.