Influence of hemoglobin on blood pressure among people with GP.Mur blood type^☆

GP.Mur is a clinically important red blood cell (RBC) type. GP.Mur and band 3 interact on the RBCs. We previously observed that healthy adults with GP.Mur type present slightly higher blood pressure (BP). Because band 3 and Hb comodulate nitric oxide (NO)-dependent vasodilation and hemoglobin (Hb) is positively associated with BP, we aimed to test whether these could contribute to higher BP in GP.Mur+ people.

We recruited 989 non-elderly adults (21% GP.Mur) free of catastrophic illness and not on cardiovascular or anti-hypertensive medication. Their body indices, blood lab data and lifestyle data were collected for analyses of potential BP-related factors (BMI, age, smoking, Hb, and GP.Mur).

BMI and age remained the most significant contributors to BP. GP.Mur slightly increased systolic BP (SBP). The direct correlation between Hb and BP was only found in Taiwanese non-anemic men, not women. After age and BMI adjusted, we estimated an increase of 1.8 mmHg and 2.6 mmHg of SBP by 1 g/dL Hb among men without and with GP.Mur type, respectively. Hb was generally lower among people expressing GP.Mur, which likely limited their larger impact on BP.

GP.Mur contributed to BP in both Hb-dependent and Hb-independent fashion. A pronounced impact of hemoglobin on BP likely requires sufficient Hb, as GP.Mur increased the sensitivity of SBP to Hb only in non-anemic Taiwanese men, and not in Taiwanese women or anemic men. The mechanism through which GP.Mur affected BP independent of Hb is unknown.