Hematocrit, hemoglobin and red blood cells are associated with vascular function and vascular structure in men

Shinji Kishimoto,Shogo Matsui,Yiming Han,Tatsuya Maruhashi,Yuji Takaeko,Ayumu Nakashima,Farina Mohamad Yusoff,Yukihito Higashi,Chikara Goto,Takahiro Harada,Takayuki Yamaji,Haruki Hashimoto,Kazuaki Chayama,Masato Kajikawa,Yasuki Kihara

doi:10.1038/s41598-020-68319-1

Abstract

High and low hematocrit (Hct) and hemoglobin (Hb) levels are associated with the risk of cardiovascular disease. The purpose of this study was to determine the relationships of Hct, Hb and red blood cells (RBCs) with vascular function and structure. We measured flow-mediated vasodilation (FMD), nitroglycerin-induced vasodilation (NID), brachial intima media thickness (IMT), and brachial-ankle pulse wave velocity (baPWV) in 807 men. The subjects were divided into six groups according to the levels of Hct, Hb and RBCs. NID was highest in the 46.0–48.9% Hct group among the six groups according to Hct levels. Brachial IMT was lowest in the 46.0–48.9% Hct group among the six groups. There were no significant differences in FMD and baPWV among the six groups. We used 46.0–48.9% Hct as a reference to define the lower tertile. The adjusted odds ratio of being in the low tertile of NID was significantly higher in the < 42.9% and ≥ 49.0% Hct groups. Adjusted odds ratio of being in the low tertile of brachial IMT was significantly lower in the < 39.9% Hct groups. Similar results were obtained for Hb and RBCs. Low and high levels of Hct, Hb and RBCs were associated with vascular smooth muscle dysfunction, and low Hct levels were associated with abnormal vascular structure. Increases in the levels of Hct, Hb and RBCs within normal ranges may have beneficial effects on the vasculature.

Highlights

High and low hematocrit (Hct) and hemoglobin (Hb) levels are associated with the risk of cardiovascular disease
There were significant differences among the six groups according to Hct levels in age, body mass index (BMI), diastolic blood pressure, total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, HbA1c, estimated glomerular filtration rate, prevalence of hypertension, prevalence of previous coronary heart disease, prevalence of previous stroke, current smokers, use of antiplatelets, use of an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, use of β-blockers, use of diuretics, use of statins, and use of insulin
The effects of Hct, Hb and red blood cells (RBCs) on vascular function and vascular structure are unclear. We demonstrated that both low and high levels of Hct, Hb and RBCs were associated with vascular smooth muscle dysfunction

Summary

Introduction

High and low hematocrit (Hct) and hemoglobin (Hb) levels are associated with the risk of cardiovascular disease. We measured flow-mediated vasodilation (FMD), nitroglycerin-induced vasodilation (NID), brachial intima media thickness (IMT), and brachialankle pulse wave velocity (baPWV) in 807 men. Adjusted odds ratio of being in the low tertile of brachial IMT was significantly lower in the < 39.9% Hct groups. Growing evidence has shown that endothelial function assessed by FMD and vascular smooth muscle function assessed by NID can serve as independent predictors of cardiovascular e vents[10,11,12]. Measurement of brachial IMT in the artery as an index of structural change of the artery and measurement of brachial-ankle pulse wave velocity (baPWV) as an index of arterial stiffness have be shown to be significantly correlated with cardiovascular risk factors[13,14]. The purpose of this study was to evaluate the relationships of levels of Hct, Hb and RBCs with vascular function and vascular structure and to evaluate the optimal cutoff levels of Hct, Hb and RBCs for maintenance of vascular function and vascular structure

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