title: Hematocrit and the risk of cardiovascular disease in a Japanese community: The Hisayama Study.
abstract: OBJECTIVE
  The association between hematocrit levels and the risk of cardiovascular disease (CVD) has been reported inconsistently. We aimed to investigate the association of hematocrit levels with the development of stroke and coronary heart disease (CHD) in a general Japanese population.
  
  
  METHODS
  A total of 2585 community-dwelling Japanese individuals aged 40 years or older in 1988 were followed up for 19 years. These subjects were divided into four groups according to the sex-specific quartiles of hematocrit at baseline.
  
  
  RESULTS
  During the follow-up, 301 subjects developed stroke (210 ischemic and 91 hemorrhagic) and 187 developed CHD. The risk of ischemic stroke was higher in both the lowest (Q1: men, ≤44.7%; women, ≤39.3%) and the highest (Q4: men, ≥49.7%; women, ≥43.8%) quartiles than in the third quartile (Q3: men, 47.1%-49.6%; women, 41.7%-43.7%) used as a reference (multivariable-adjusted hazard ratios [95% confidence intervals]: Q1, 1.55 [0.99-2.43]; Q2, 1.44 [0.93-2.23]; Q3, 1.00; and Q4, 1.62 [1.06-2.50]; P = 0.86 for trend). In contrast, hematocrit levels and the risk of hemorrhagic stroke showed a linear inverse association (Q1, 1.91 [1.03-3.54]; Q2, 1.26 [0.68-2.34]; Q3, 1.00; and Q4, 0.81 [0.41-1.61]; P = 0.009 for trend). The risk of CHD increased significantly in Q4 (Q1, 1.13 [0.71-1.80]; Q2, 1.08 [0.69-1.71]; Q3, 1.00; and Q4, 1.60 [1.04-2.46]; P = 0.13 for trend).
  
  
  CONCLUSIONS
  Our findings suggest that both elevated and decreased hematocrit levels are associated with an increased risk of CVD, but the influence of hematocrit is different among subtypes of CVD.
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Gotoh
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. Electronic address: junhata@cohort.med.kyushu-u.ac.jp.
authors.forename: Jun
authors.initials: J
authors.lastname: Hata
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Ninomiya
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Hirakawa
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nagata
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Mukai
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Masayo
authors.initials: M
authors.lastname: Fukuhara
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Fumie
authors.initials: F
authors.lastname: Ikeda
authors.affiliation: Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Ago
authors.affiliation: Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Takanari
authors.initials: T
authors.lastname: Kitazono
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kiyohara
mesh_terms: D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000097:blood / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D003327:Coronary Disease / Q000097:blood / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006400:Hematocrit; D006801:Humans; D015994:Incidence; D020300:Intracranial Hemorrhages / Q000097:blood / Q000453:epidemiology; D007564:Japan / Q000453:epidemiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D020521:Stroke / Q000097:blood / Q000453:epidemiology; D013997:Time Factors
keywords: Coronary heart disease; Epidemiology; General populations; Hematocrit; Stroke