title: Historic air pollution exposure and long-term mortality risks in England and Wales: prospective longitudinal cohort study.
abstract: BACKGROUND
  Long-term air pollution exposure contributes to mortality but there are few studies examining effects of very long-term (>25 years) exposures.
  
  
  METHODS
  This study investigated modelled air pollution concentrations at residence for 1971, 1981, 1991 (black smoke (BS) and SO2) and 2001 (PM10) in relation to mortality up to 2009 in 367,658 members of the longitudinal survey, a 1% sample of the English Census. Outcomes were all-cause (excluding accidents), cardiovascular (CV) and respiratory mortality.
  
  
  RESULTS
  BS and SO2 exposures remained associated with mortality decades after exposure-BS exposure in 1971 was significantly associated with all-cause (OR 1.02 (95% CI 1.01 to 1.04)) and respiratory (OR 1.05 (95% CI 1.01 to 1.09)) mortality in 2002-2009 (ORs expressed per 10 μg/m(3)). Largest effect sizes were seen for more recent exposures and for respiratory disease. PM10 exposure in 2001 was associated with all outcomes in 2002-2009 with stronger associations for respiratory (OR 1.22 (95% CI 1.04 to 1.44)) than CV mortality (OR 1.12 (95% CI 1.01 to 1.25)). Adjusting PM10 for past BS and SO2 exposures in 1971, 1981 and 1991 reduced the all-cause OR to 1.16 (95% CI 1.07 to 1.26) while CV and respiratory associations lost significance, suggesting confounding by past air pollution exposure, but there was no evidence for effect modification. Limitations include limited information on confounding by smoking and exposure misclassification of historic exposures.
  
  
  CONCLUSIONS
  This large national study suggests that air pollution exposure has long-term effects on mortality that persist decades after exposure, and that historic air pollution exposures influence current estimates of associations between air pollution and mortality.
authors: UK Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK Imperial College Healthcare NHS Trust, London, UK.
authors: Anna
authors: A
authors: Hansell
authors: UK Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK.
authors: Rebecca E
authors: RE
authors: Ghosh
authors: UK Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK.
authors: Marta
authors: M
authors: Blangiardo
authors: Department of Epidemiology and Biostatistics, Imperial College, London, UK.
authors: Chloe
authors: C
authors: Perkins
authors: UK Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK Swiss Tropical and Public Health Institute, Basel, Switzerland University of Basel, Basel, Switzerland.
authors: Danielle
authors: D
authors: Vienneau
authors: UK Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK.
authors: Kayoung
authors: K
authors: Goffe
authors: Department of Epidemiology and Biostatistics, Imperial College, London, UK.
authors: David
authors: D
authors: Briggs
authors: UK Small Area Health Statistics Unit, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK.
authors: John
authors: J
authors: Gulliver
mesh_terms: D000397:Air Pollution / Q000032:analysis / Q000266:history*; D004739:England; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis / Q000266:history*; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D008137:Longitudinal Studies; D010087:Oxides / Q000009:adverse effects / Q000266:history*; D052638:Particulate Matter / Q000009:adverse effects / Q000266:history*; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000209:etiology / Q000266:history* / Q000401:mortality; D012307:Risk Factors; D012906:Smoke / Q000009:adverse effects; D013457:Sulfur Compounds / Q000009:adverse effects / Q000266:history*; D013997:Time Factors; D014852:Wales
chemical_list: D010087:Oxides; D052638:Particulate Matter; D012906:Smoke; D013457:Sulfur Compounds; C405951:sulfur monoxide