Article type: Research Article
Authors: Tabara, Yasuharu | Igase, Michiya | Saito, Isao; | Nishida, Wataru | Kohara, Katsuhiko; | Sakurai, Susumu; | Kawamura, Ryoichi | Okada, Yoko | Hitsumoto, Shinichi | Onuma, Hiroshi; | Nagai, Tokihisa | Takata, Yasunori | Uetani, Eri | Takita, Rie | Kido, Tomoko | Ochi, Namiko | Osawa, Haruhiko; | Tanigawa, Takeshi; | Miki, Tetsuro;
Affiliations: Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan | Department of Geriatric Medicine, Ehime University Graduate School of Medicine, Toon City, Japan | Department of Molecular and Genetic Medicine, Ehime University Graduate School of Medicine, Toon City, Japan | Department of Public Health, Ehime University Graduate School of Medicine, Toon City, Japan | Division of Anti-aging and Genetics, Ehime University Proteo-Medicine Research Center, Toon City, Japan | Medical Welfare Support Center, Ehime University Hospital, Toon, Japan | Department of Clinical Laboratory Science, Faculty of Health Care, Tenri Health Care University, Tenri, Japan
Note: [] Corresponding author: Yasuharu Tabara, Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Shogoinkawaramachi 53, Sakyo-ku, Kyoto 606-8507, Japan. Tel.: +81 75 366 7407; Fax: +81 75 751 4167; E-mail: tabara@genome.med.kyoto-u.ac.jp
Abstract: BACKGROUND: Elevated hematocrit levels have been suggested to be an independent determinant of insulin resistance and type 2 diabetes. To clarify the diagnostic significance of hematocrit level, we investigated the association with hemodynamic profiles, insulin resistance and insulin sensitivity, arterial properties, and asymptomatic cerebrovascular damage in a general Japanese population. METHODS: This study included 1,978 participants from two independent cohorts. Insulin sensitivity was assessed by the oral 75 g glucose tolerance test. Carotid ultrasonography was performed to evaluate atherosclerosis and wall shear stress. Periventricular hyperintensity and lacunar infarction were assessed by brain magnetic resonance imaging. RESULTS: Hematocrit quartile showed a stepwise association with insulin sensitivity (Q1: 2.2 ± 0.7, Q2: 2.0 ± 0.7, Q3: 1.9 ± 0.7, Q4: 1.8 ± 0.6, p < 0.001) and insulin resistance (1.0 ± 0.6, 1.2 ± 0.7, 1.3 ± 0.8, 1.5 ± 1.0, p < 0.001). Multiple linear regression analysis adjusted for possible covariates identified hematocrit as an independent determinant of insulin sensitivity (β = −0.074, p = 0.019) and insulin resistance (β = 0.115, p < 0.001). However, this association was lost after further adjustment for visceral fat area and plasma alanine aminotransferase level. Further, no significant association was observed between hematocrit and carotid intima-media thickness (p = 0.306) where as wall shear stress was inversely associated with the carotid atherosclerosis (r = −0.250, p < 0.001). In contrast, a low hematocrit level was independently associated with periventricular hyperintensity (odds ratio 0.87 (95% CI 0.80–0.95), p = 0.001). CONCLUSION: Hematocrit was positively associated with insulin resistance and insulin sensitivity. This association was epiphenomenon of visceral and hepatic adiposity. Conversely, low hematocrit was a significant risk factor for periventricular hyperintensity independent of insulin resistance.
Keywords: Hematocrit, insulin resistance, atherosclerosis, cerebrovascular disease
DOI: 10.3233/CH-2012-1634
Journal: Clinical Hemorheology and Microcirculation, vol. 55, no. 3, pp. 297-311, 2013
