title: Blood viscosity as a forgotten factor and its effect on pulmonary flow.
abstract: BACKGROUND
  The effect of smoking on blood viscosity is widely known. There are, however, few studies on the effect of blood viscosity on pulmonary circulation.
  
  
  METHODS
  We aimed to observe the relationship between blood viscosity and pulmonary circulation among smokers and non-smokers. The study comprised 114 subjects in three groups: group 1, ex-smokers; group 2, smoked at least 10 packs/year and still smoking; group 3, never smoked. Blood viscosity (BV), pulmonary blood flow (PBF), and right ventricular systolic pressure (RVSP) were measured in all subjects.
  
  
  RESULTS
  PBF was significantly lower in group 1 compared with group 3 (p < 0.05). BV in group 1 was significantly higher than group 3 (p < 0.05) while BV in group 2 was significantly higher than group 3 (p < 0.05). PBF in group 2 was significantly lower than group 3 (p = 0.01).
  
  
  CONCLUSIONS
  We believe that BV is a significant and forgotten factor that plays an important role in pulmonary and cardiovascular diseases. BV may affect PF even during the course of smoking, and before the clinical onset of chronic obstructive pulmonary disease (COPD). Therefore, individuals at risk of pulmonary hypertension could be detected earlier with a simple blood test.
authors.affiliation: Department of Chest Disease, Haseki Training and Research Hospital, Millet St Fatih, Istanbul, 34096, Turkey. gulfidan70@gmail.com.
authors.forename: Gulfidan
authors.initials: G
authors.lastname: Cakmak
authors.affiliation: Department of Biophysics, Istanbul University Cerrahpasa Medical Faculty, Fatih, Istanbul, 34098, Turkey.
authors.forename: Fatma Ates
authors.initials: FA
authors.lastname: Alkan
authors.affiliation: Department of Cardiology Disease, Haseki Training and Research Hospital, Millet St Fatih, Istanbul, 34096, Turkey.
authors.forename: Kazim
authors.initials: K
authors.lastname: Korkmaz
authors.affiliation: Department of Family Practitioners, Haseki Training and Research Hospital, Millet St Fatih, Istanbul, 34096, Turkey.
authors.forename: Zuhal Aydan
authors.initials: ZA
authors.lastname: Saglam
authors.affiliation: Department of Biophysics, Istanbul University Cerrahpasa Medical Faculty, Fatih, Istanbul, 34098, Turkey.
authors.forename: Denizhan
authors.initials: D
authors.lastname: Karis
authors.affiliation: Department of Internal Disease, Haseki Training and Research Hospital, Millet St Fatih, Istanbul, 34096, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Yenigun
authors.affiliation: Department of Biophysics, Istanbul University Cerrahpasa Medical Faculty, Fatih, Istanbul, 34098, Turkey.
authors.forename: Meltem
authors.initials: M
authors.lastname: Ercan