title: Hemoglobin Concentration and Risk of Incident Stroke in Community-Living Adults.
abstract: In previous observational studies, hemoglobin concentrations have been associated with an increased risk of stroke. However, these studies were limited by a relatively low number of stroke events, making it difficult to determine whether the association of hemoglobin and stroke differed by demographic or clinical factors.
  
  
  
  Using Cox proportional hazards analysis and Kaplan-Meier plots, we examined the association of baseline hemoglobin concentrations with incident stroke in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a cohort of black and white adults aged ≥45 years.
  
  
  
  A total of 518 participants developed stroke over a mean 7±2 years of follow-up. There was a statistically significant interaction between hemoglobin and sex (P=0.05) on the risk of incident stroke. In Cox regression models adjusted for demographic and clinical variables, there was no association of baseline hemoglobin concentration with incident stroke in men, whereas in women, the lowest (<12.4 g/dL) and highest (>14.0 g/dL) quartiles of hemoglobin were associated with higher risk of stroke when compared with the second quartile (12.4-13.2 g/dL; quartile 1: hazard ratio, 1.59; 95% confidence interval, 1.09-2.31; quartile 2: referent; quartile 3: hazard ratio, 0.91; 95% confidence interval, 0.59-1.38; quartile 4: hazard ratio, 1.59; 95% confidence interval, 1.08-2.35). Similar results were observed in models stratified by hemoglobin and sex and when hemoglobin was modeled as a continuous variable using restricted quadratic spline regression.
  
  
  
  Lower and higher hemoglobin concentrations were associated with a higher risk of incident stroke in women. No such associations were found in men.
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.).
authors.forename: Bhupesh
authors.initials: B
authors.lastname: Panwar
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.).
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Judd
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.).
authors.forename: David G
authors.initials: DG
authors.lastname: Warnock
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.).
authors.forename: William M
authors.initials: WM
authors.lastname: McClellan
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.).
authors.forename: John N
authors.initials: JN
authors.lastname: Booth
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.).
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
authors.affiliation: From the Departments of Medicine (B.P., D.G.W., J.N.B., P.M., O.M.G.), Biostatistics (S.E.J.), and Epidemiology (J.N.B., P.M., O.M.G.), University of Alabama at Birmingham; and Departments of Epidemiology and Medicine, Emory University, Atlanta, GA (W.M.M.). ogutierrez@uabmc.edu.
authors.forename: Orlando M
authors.initials: OM
authors.lastname: Gutiérrez
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044383:Black People; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012306:Risk; D012737:Sex Factors; D020521:Stroke / Q000097:blood / Q000453:epidemiology*; D044465:White People
chemical_list: D006454:Hemoglobins
keywords: anemia; cohort studies; hematocrit; hemoglobins; renal insufficiency, chronic; stroke