title: Influence of Cardiovascular Fitness and Muscle Strength in Early Adulthood on Long-Term Risk of Stroke in Swedish Men.
abstract: OBJECTIVE
  Low cardiovascular fitness (fitness) in mid- and late life is a risk factor for stroke. However, the respective effects on long-term stroke risk of fitness and muscle strength in early adulthood are unknown. Therefore, we analyzed these in a large cohort of young men.
  
  
  METHODS
  We performed a population-based longitudinal cohort study of Swedish male conscripts registered in 1968 to 2005. Data on fitness (by the cycle ergometric test; n=1 166 035) and muscle strength (n=1,563,750) were trichotomized (low, medium, and high). During a 42-year follow-up, risk of stroke (subarachnoidal hemorrhage, intracerebral hemorrhage, and ischemic stroke) and fatality were calculated with Cox proportional hazards models. To identify cases, we used the International Classification of Diseases-Eighth to Tenth Revision in the Hospital Discharge Register and the Cause of Death Register.
  
  
  RESULTS
  First-time stroke events were identified (subarachnoidal hemorrhage, n=895; intracerebral hemorrhage, n=2904; ischemic stroke, n=7767). For all stroke and fatality analysis any type of first-time stroke was recorded (n=10,917). There were inverse relationships in a dose-response fashion between fitness and muscle strength with any stroke (adjusted hazard ratios for the lowest, compared with the highest, tertile of each 1.70 [1.50-1.93] and 1.39 [1.27-1.53], respectively). There were stronger associations for fatal stroke. All 3 stroke types displayed similar associations. Associations between fitness and stroke remained when adjusted for muscle strength, whereas associations between muscle strength and stroke weakened/disappeared when adjusted for fitness.
  
  
  CONCLUSIONS
  At the age of 18 years, low fitness and to a lesser degree low muscle strength were independently associated with an increased future stroke risk.
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.). david.aberg@medic.gu.se.
authors.forename: N David
authors.initials: ND
authors.lastname: Åberg
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: H Georg
authors.initials: HG
authors.lastname: Kuhn
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Jenny
authors.initials: J
authors.lastname: Nyberg
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Margda
authors.initials: M
authors.lastname: Waern
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Peter
authors.initials: P
authors.lastname: Friberg
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Johan
authors.initials: J
authors.lastname: Svensson
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Kjell
authors.initials: K
authors.lastname: Torén
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Annika
authors.initials: A
authors.lastname: Rosengren
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Maria A I
authors.initials: MA
authors.lastname: Åberg
authors.affiliation: From the Department of Internal Medicine, Institute of Medicine (N.D.Å., J.S.), Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology (H.G.K., J.N., M.A.I.Å., M.N.), Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology (M.W.), Department of Molecular and Clinical Medicine, Institute of Medicine (P.F., A.R.), Occupational and Environmental Medicine, Institute of Medicine (K.T.), and Department of Primary Health Care, Institute of Medicine (M.A.I.Å.), Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden; and Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia (M.N.).
authors.forename: Michael
authors.initials: M
authors.lastname: Nilsson
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005080:Exercise Test / Q000379:methods; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D011159:Population Surveillance; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis* / Q000453:epidemiology*; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
keywords: epidemiology; exercise; incidence; muscles; stroke