title: Cardiovascular fitness in early adulthood and future suicidal behaviour in men followed for up to 42 years.
abstract: BACKGROUND
  Cardiovascular fitness influences many aspects of brain function. However, the relationship between cardiovascular fitness and suicidal behaviour is unknown. Therefore, we aimed to determine whether cardiovascular fitness at age 18 years is associated with future risk of suicide attempt/death.
  
  
  METHODS
  We performed a population-based Swedish longitudinal cohort study of male conscripts with no previous or ongoing mental illness (n = 1,136,527). The conscription examination, which took place during 1968-2005, included the cycle ergonometric test and tests of cognitive performance. Future risk of suicide attempt/death over a 5- to 42-year follow-up period was calculated with Cox proportional hazards models controlling for several confounders including familial factors.
  
  
  RESULTS
  At least one suicide attempt was recorded for 12,563 men. Death by suicide without a prior attempt was recorded in 4814 additional individuals. In fully adjusted models low cardiovascular fitness was associated with increased risk for future attempt/death by suicide [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.64-1.94]. The HR changed only marginally after exclusion of persons who received in-patient care for depression (HR 1.76, 95% CI 1.61-1.94). Poor performance on both the cardiovascular fitness and cognitive tests was associated with a fivefold increased risk of suicide attempt or suicide death (HR 5.46, 95% CI 4.78-6.24).
  
  
  CONCLUSIONS
  Lower cardiovascular fitness at age 18 years was, after adjustment for a number of potential confounders, associated with an increased risk of attempt/death by suicide in adulthood. It remains to be clarified whether interventions designed to improve fitness in teens can influence the risk of suicidal behaviour later in life.
authors.affiliation: Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: M A I
authors.initials: MA
authors.lastname: Åberg
authors.affiliation: Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Nyberg
authors.affiliation: Occupational and Environmental Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Torén
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Sörberg
authors.affiliation: Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: H G
authors.initials: HG
authors.lastname: Kuhn
authors.affiliation: Department of Psychiatry and Neurochemistry, Neuropsychiatric Epidemiology Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Waern
mesh_terms: D000293:Adolescent; D000328:Adult; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000517:prevention & control*; D003863:Depression / Q000453:epidemiology; D005544:Forecasting; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology*; D016016:Proportional Hazards Models; D012042:Registries / Q000706:statistics & numerical data; D012306:Risk; D013405:Suicide / Q000706:statistics & numerical data; D013406:Suicide, Attempted / Q000706:statistics & numerical data; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult