title: Stressful life events are not associated with the development of dementia.
abstract: BACKGROUND
  The impact of stressful life events as a risk factor of dementia diseases is inconclusive. We sought to determine whether stressful negative life events are associated with incidental dementia in a population-based study with long-term follow-up. We also tested the hypothesis that the occurrence of positive life events could mitigate or overcome the possible adverse effects of negative life events on dementia conversion.
  
  
  METHODS
  The study involved 2,462 dementia-free participants aged 55 years and older. Information on life events was ascertained at baseline from a comprehensive Life Event Inventory, which included 56 questions about specific life events. For each life event, the emotional impact (both positive and negative) and emotional adjustment were asked for.
  
  
  RESULTS
  During follow-up, 423 participants developed dementia; of these, 240 developed Alzheimer's disease (AD). Cox regression analysis showed no association between the total number of negative life events and the incidence of dementia when adjusted solely for age and gender (hazard ratio = 0.97, 95% CI = 0.92-1.02), or with multiple adjustments for a range of covariates (hazard ratio = 0.96, 95% CI = 0.91-1.01). Similarly, neither emotional impact nor emotional adjustment to these life events was associated with incident dementia. A separate analysis of AD did not alter the results.
  
  
  CONCLUSIONS
  The result of this population-based study finds no association between negative or positive life events and dementia. Accordingly, our results reject the hypothesis that stressful life events trigger the onset of dementia diseases.
authors.affiliation: Centre for Population Studies/Ageing and Living Conditions, and Department of Psychology, Umeå University, Umeå, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Sundström
authors.forename: Michael
authors.initials: M
authors.lastname: Rönnlund
authors.forename: Rolf
authors.initials: R
authors.lastname: Adolfsson
authors.forename: Lars-Göran
authors.initials: LG
authors.lastname: Nilsson
mesh_terms: D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology / Q000209:etiology / Q000523:psychology; D003704:Dementia / Q000453:epidemiology / Q000209:etiology* / Q000523:psychology; D005260:Female; D006801:Humans; D008016:Life Change Events; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology