ABO blood types and cancer risk--a cohort study of 339,432 subjects in Taiwan

BACKGROUND: The associations of laboratory-based ABO phenotypes with cancer risks and mortality have not been systematically determined.

METHODS: The study subjects were 339,432 healthy individuals with laboratory-based blood types from a Taiwan cohort.

RESULTS: Compared 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.

CONCLUSION: Cancer 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).