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Clinical Hemorheology and Microcirculation xx (20xx) x–xx DOI 10.3233/CH-141862 IOS Press
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Amparo Vay´aa,∗ , Ana Sarnagoa , Oscar Fustera , Rafael Alisb and Marco Romagnolib a
Hemorheology and Haemostasis Unit, Service of Clinical Pathology, La Fe University Hospital, Valencia, Spain b University Research Institute “Dr. Vi˜na Giner”, Molecular and Mitochondrial Medicine, Catholic University of Valencia, “San Vicente M´artir”, Valencia, Spain
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Abstract. Red blood cell distribution width (RDW) is a routine red blood cell count parameter which has been shown to be associated with inflammatory parameters. Recently, some authors proposed that RDW seems to be a marker of an adverse lipidic profile. In order to clarify whether RDW is related to inflammation, plasma lipids, or both, we determined anthropometric, hematimetric, inflammatory and lipidic parameters in 1111 healthy subjects. RDW correlated directly with age, body mass index (BMI), inflammatory parameters (plasma viscosity, erythrocyte sedimentation rate (ESR), fibrinogen, leukocyte and neutrophil count), and inversely with iron and hematimetric parameters (P < 0.05). When subjects were divided according to gender, RDW correlated inversely with triglycerides only in women (P < 0.05). When subjects were classified into RDW-quartiles, increased RDW values were accompanied by decreased serum iron levels and hematimetric indices (P < 0.01), whereas age and inflammatory markers increased according to RDW-quartiles (P < 0.001 and P < 0.05, respectively). However, plasma lipids did not change with increasing RDW-quartiles (P > 0.05). In the linear regression analysis, age, hemoglobin, MCV (beta coefficient: 0.202, −0.234, −0.316, P < 0.001) and fibrinogen (beta coefficient: 0.059, P = 0.048) were the only independent predictors of RDW. The present study indicates that RDW is associated with inflammatory markers and hematimetric indices, but not with plasma lipid levels in a healthy population.
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Influence of inflammatory and lipidic parameters on red blood cell distribution width in a healthy population
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Keywords: Red blood cell distribution width, inflammatory markers, lipids
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1. Introduction
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Red blood cell distribution width (RDW) is a routine blood cell count parameter that reflects size variations in erythrocytes, indicating the degree of anisocytosis [6]. RDW has been used traditionally in the differential diagnosis of microcytic anemia, although increased RDW is also commonly found in iron, folate and vitamin B12 deficiency [3, 4, 6] In the last few years, high RDW values have been reported in several cardiovascular disorders such as ischemic heart disease [26], acute and chronic heart failure [7, 8], and stroke [1], inflammatory diseases [13, 23] and it has been shown to be associated with all-cause, cardiac and non-cardiac mortality [2, 18, 19]. However, the pathogenic mechanism underlying RDW with several of the above-mentioned clinical situations is not established. Some authors suggest that RDW may be considered an inflammatory biomarker as it has been correlated with several inflammatory parameters, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), in
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∗ Corresponding author: Amparo Vay´a, MD, PhD, Hemorheology and Hemostasis Unit, Service of Clinical Pathology, La Fe University Hospital, Avda. de Campanar, 21, 46009, Valencia, Spain. Tel./Fax: +34 963862714; E-mail: vaya
[email protected].
1386-0291/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
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A. Vay´a et al. / Influence of inflammatory and lipidic parameters
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2. Patients and methods
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a large cohort of unselected outpatients [16]. The same author, in a recent paper, found that high RDW is associated with a globally unfavorable lipid profile as it correlates inversely with HDL-cholesterol in both men and women, and directly with hypertriglyceridemia, and with the COL/HDL ratio only in women [15]. In order to clarify whether RDW is related to inflammation, plasma lipids, or both, we analyzed RDW along with anthropometric, hematimetric, inflammatory and lipidic parameters in a healthy Mediterranean population.
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2.1. Laboratory methods
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Venous blood samples were obtained by sterile antecubital venipuncture after overnight fasting for 12 h between 08:00 h and 10:00 h, with a minimum stasis. Blood was collected in vacuum tubes containing trisodium citrate for fibrinogen and ESR measurement, EDTA K3 for the hematological and hemorheological analysis and dry tubes for the biochemical determinations. Biochemical parameters (glucose, total-cholesterol, HDL-cholesterol and triglycerides) were evaluated by enzymatic techniques and iron by colorimetric techniques in an AU5400 Olympus Autoanalyzer (Mishima, Japan). LDL-cholesterol was calculated using the Friedewald formula [10]. CRP was determined by immunoturbidity in the same autoanalyzer above mentioned. Basic hematological parameters were determined by a Sysmex XE- 2100 (Roche Diagnostics S.L., Barcelona, Spain), including white blood cell (WBC) and neutrophil count, hemoglobin, hematocrit (Hct) and cellular indices (i.e., mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and RDW). Fibrinogen was evaluated in an ACL-TOP autoanalyzer (Instrumentation Laboratory, Milan, Italy). ESR was performed according to the Westergren technique by means of a Viscomatic 30 Plus Analyzer (Menarini, Brna, Spain). Plasma viscosity was determined in a capillary plasma viscosimeter (Fresenius GmbH, Germany) at 37◦ C. Waist circumference (cm) was measured by well-trained medical staff using the same instruments for all the participants. Height (cm) and weight (kg) were recorded, and BMI was calculated (kg/m2 ). Laboratory values are given in conventional units; conversions to Syst`eme International units are as follows: glucose (nmol/L), multiply by 0.0555; Total-cholesterol, HDL-cholesterol and LDL-cholesterol (mmol/L), multiply by 0.0259; triglycerides (mmol/L), multiply by 0.0113; iron (mol/L), multiply by 0.179; CRP (nmol/L), multiply by 9.524 and fibrinogen (mol/L), multiply by 0.0294.
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Between 2007 and 2013, 1111 healthy volunteers were examined in our laboratory. The group comprised 549 men and 562 women, aged 44 ± 14 and 45 ± 14, respectively. They belonged to our hospital staff and came to the Preventive Medicine service for a routine check-up. Subjects were from the same geographical area (Eastern Spain) and were all Caucasians. Exclusion criteria were organic, malignant, hematological, infectious or inflammatory diseases, previous history of ischemic heart disease or stroke and previous thrombo-embolism. Thirty-eight subjects (7 men and 31 women) were anemic (3.4%), according to the WHO criteria; i.e., hemoglobin
