ABO and Rhesus blood groups and risk of type 2 diabetes: evidence from the large E3N cohort study

Aims/hypothesis: The objective of this study was to evaluate the relationship of ABO blood type (A, B, AB and O), Rhesus factor (positive or negative) and a combination of the two (ABO × Rhesus) with type 2 diabetes mellitus risk.

Methods: In total, 82,104 women from the large prospective E3N cohort were followed between 1990 and 2008. Multivariate Cox regression models were used to estimate HRs and 95% CIs.

Results: Those with either the A (HR 1.10 [95% CI 1.02, 1.18]) or B (HR 1.21 [95% CI 1.07, 1.36]) group were at increased risk of type 2 diabetes mellitus compared with those with the O group. The association with the AB group did not reach statistical significance (HR 1.17 [95% CI 0.99, 1.39]). There was no difference in type 2 diabetes mellitus risk between Rhesus positive and negative groups (HR 0.96 [95% CI 0.88, 1.05]). When the universal donors (O⁻) were taken as the reference category, we observed an increased risk for both A⁺ (HR 1.17 [95% CI 1.02, 1.35]) and A⁻ (HR 1.22 [95% CI 1.03, 1.45]) individuals. The greatest increase in risk was seen for those with the B⁺ blood group (HR 1.35 [95% CI 1.13, 1.60]). We also observed a greater type 2 diabetes mellitus risk for those with the AB⁺ group (HR 1.26 [95% CI 1.02, 1.57]). Adjustment for fasting plasma glucose and lipid concentrations in a case–control subsample did not alter the associations.

Conclusions/interpretation: This study suggests that people with the O blood type have a lower risk of developing type 2 diabetes mellitus. Therefore, blood group should be investigated in future clinical and epidemiological studies on diabetes, and further pathophysiological research is needed to determine why individuals with blood type O have a lower risk of type 2 diabetes mellitus.