title: Pulmonary function as a risk factor for dementia death: an individual participant meta-analysis of six UK general population cohort studies.
abstract: BACKGROUND
  In addition to being associated with all-cause mortality and cardiovascular disease mortality, lung function has been linked with dementia. However, existing studies typically provide imprecise estimates due to small numbers of outcome events and are based on unrepresentative samples of the general population.
  
  
  METHODS
  Individual participant meta-analysis of six cohort studies from the Health Survey for England and the Scottish Health Survey (total N=54 671). Dementia-related mortality was identified by mention of dementia on any part of the death certificate (mean follow-up 11.7 years). Study-specific Cox proportional hazard models of the association between lung function and dementia-related death were pooled using random effect meta-analysis to produce overall results.
  
  
  RESULTS
  There was a dose-response association between poorer lung function and a higher risk of dementia-related death (age- and sex-adjusted HR compared to highest quartile of forced expiratory volume in 1 s (FEV1), 95% CI: second quartile 1.32, 0.99 to 1.76; third quartile 1.78, 1.30 to 2.43; fourth (lowest) quartile 2.74, 1.73 to 4.32). There was no significant heterogeneity in study-specific estimates (I(2)=0%). Controlling for height, socioeconomic status, smoking and general health attenuated but did not remove the association (second quartile 1.15, 0.82 to 1.62; third quartile 1.37, 0.96 to 1.94; fourth quartile 2.09, 1.17 to 3.71). Results for forced vital capacity and peak flow were similar.
  
  
  CONCLUSIONS
  In these general population samples, the relation between three measures of lung function and dementia death followed a dose-response gradient. Being in the bottom quartile of lung function was associated with a doubling of the risk.
authors.affiliation: Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK Scottish Dementia Clinical Research Network, NHS Scotland, UK Centre for Cognitive Ageing & Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK Division of Psychiatry, University of Edinburgh, Edinburgh, UK.
authors.forename: Tom C
authors.identifier: http://orcid.org/0000-0001-9797-2188
authors.initials: TC
authors.lastname: Russ
authors.affiliation: Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK Scottish Dementia Clinical Research Network, NHS Scotland, UK Centre for Cognitive Ageing & Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK.
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.affiliation: Department of Epidemiology and Public Health, University College, London, UK Charles Perkins Centre, University of Sydney, Australia Exercise and Sport Sciences, Faculty of Health Sciences, University of Sydney, Australia.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Stamatakis
authors.affiliation: Department of Epidemiology and Public Health, University College, London, UK.
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimäki
authors.affiliation: Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK Centre for Cognitive Ageing & Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK Department of Epidemiology and Public Health, University College, London, UK.
authors.forename: G David
authors.initials: GD
authors.lastname: Batty
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003704:Dementia / Q000401:mortality*; D004739:England / Q000453:epidemiology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006306:Health Surveys; D006801:Humans; D008168:Lung / Q000502:physiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D016016:Proportional Hazards Models; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology; D013147:Spirometry / Q000295:instrumentation / Q000379:methods; D014797:Vital Capacity / Q000502:physiology
keywords: AGEING; EPIDEMIOLOGY; MENTAL HEALTH; META ANALYSIS