ABO blood types and cancer risk—A cohort study of 339,432 subjects in Taiwan

• In a prospective cohort of 339,432 Asians, blood type AB was associated with lower over-all cancer risk and mortality.
• Compared to blood type O, an elevated pancreatic cancer risk was associated with blood types A, B, and AB.
• Compared to blood type O, blood type A was associated with stomach cancer risk.
• Kidney cancer risk was inversely associated with blood type AB.
• Our study provides evidence of blood type influencing cancer risk; further studies in different populations are warranted.

BackgroundThe associations of laboratory-based ABO phenotypes with cancer risks and mortality have not been systematically determined.MethodsThe study subjects were 339,432 healthy individuals with laboratory-based blood types from a Taiwan cohort.ResultsCompared to blood type O, blood type A was significantly associated with an elevated risk of stomach cancer incidence (Hazard Ratio [HR], 1.38 [95% CI, 1.11–1.72]) and mortality (HR, 1.38 [95% CI, 1.02–1.86]) compared with blood type O, after adjusting for age, sex, education, smoking, alcohol drinking, physical activity, and body mass index. Non-O blood types were associated with an elevated risk of pancreatic cancer, with blood type B reaching statistical significance for incidence (HR, 1.59 [95% CI, 1.02–2.48]) and mortality (HR, 1.63 [95% CI, 1.02–2.60]). In contrast, kidney cancer risk was inversely associated with blood type AB (HR, 0.41 [95% CI, 0.18–0.93]) compared to type O.ConclusionCancer risks vary in people with different ABO blood types, with elevated risks of stomach cancer associated with blood type A and pancreatic cancer associated with non-O blood types (A, B, and AB).