ABO blood group system and risk of brain tumors: A retrospective case–control study in Northeast of China

Aim: The findings on ABO blood groups and risk of brain tumors are inconsistent and contradictory. The aim of this study was to investigate this association through a case–control study in the northeast of China. Methods: Between 2001 and 2016, a total of 2077 cases with glioma (n = 612), meningioma (n = 816), and pituitary adenoma (n = 649), and 2716 healthy controls were retrospectively included in this study. Data were statistically analyzed by comparing to the participants with blood type O; after adjusting for age, gender, smoking, and alcohol status. Results: A comparatively higher incidence of glioma was observed with blood type B and AB cases (adjusting odds ratio [OR] = 1.389 [1.087–1.777] and 95% confidence interval [CI] = 2.260 [1.572–3.250]). A comparatively lesser incidence of pituitary adenoma was observed with blood type B and AB cases (adjusting OR = 0.561 [0.445–0.706] and 95% CI = 0.358 [0.307–0.619]). Moreover, a comparatively lesser incidence of meningioma was observed with blood type B cases (adjusting OR and 95% CI of 0.577 [0.463–0.717]). Conclusion: Blood type B and AB could be associated with a higher incidence of glioma and lesser incidence of pituitary adenoma, with a decreased risk of meningioma in blood type B individuals. Future studies are needed to reconfirm our finding and explore the underlying mechanisms linking brain tumors to ABO blood types.