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

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 x Rhesus) with type 2 diabetes mellitus risk. 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. 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. 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.