title: Global association of air pollution and heart failure: a systematic review and meta-analysis.
abstract: BACKGROUND
  Acute exposure to air pollution has been linked to myocardial infarction, but its effect on heart failure is uncertain. We did a systematic review and meta-analysis to assess the association between air pollution and acute decompensated heart failure including hospitalisation and heart failure mortality.
  
  
  METHODS
  Five databases were searched for studies investigating the association between daily increases in gaseous (carbon monoxide, sulphur dioxide, nitrogen dioxide, ozone) and particulate (diameter <2·5 μm [PM2·5] or <10 μm [PM10]) air pollutants, and heart failure hospitalisations or heart failure mortality. We used a random-effects model to derive overall risk estimates per pollutant.
  
  
  RESULTS
  Of 1146 identified articles, 195 were reviewed in-depth with 35 satisfying inclusion criteria. Heart failure hospitalisation or death was associated with increases in carbon monoxide (3·52% per 1 part per million; 95% CI 2·52-4·54), sulphur dioxide (2·36% per 10 parts per billion; 1·35-3·38), and nitrogen dioxide (1·70% per 10 parts per billion; 1·25-2·16), but not ozone (0·46% per 10 parts per billion; -0·10 to 1·02) concentrations. Increases in particulate matter concentration were associated with heart failure hospitalisation or death (PM2·5 2·12% per 10 μg/m(3), 95% CI 1·42-2·82; PM10 1·63% per 10 μg/m(3), 95% CI 1·20-2·07). Strongest associations were seen on the day of exposure, with more persistent effects for PM2·5. In the USA, we estimate that a mean reduction in PM2·5 of 3·9 μg/m(3) would prevent 7978 heart failure hospitalisations and save a third of a billion US dollars a year.
  
  
  CONCLUSIONS
  Air pollution has a close temporal association with heart failure hospitalisation and heart failure mortality. Although more studies from developing nations are required, air pollution is a pervasive public health issue with major cardiovascular and health economic consequences, and it should remain a key target for global health policy.
  
  
  BACKGROUND
  British Heart Foundation.
authors.affiliation: BHF/University Centre for Cardiovascular Science, University of Edinburgh, UK.
authors.forename: Anoop S V
authors.initials: AS
authors.lastname: Shah
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Langrish
authors.forename: Harish
authors.initials: H
authors.lastname: Nair
authors.forename: David A
authors.initials: DA
authors.lastname: McAllister
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Hunter
authors.forename: Ken
authors.initials: K
authors.lastname: Donaldson
authors.forename: David E
authors.initials: DE
authors.lastname: Newby
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Mills
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects*; D002248:Carbon Monoxide / Q000032:analysis / Q000633:toxicity; D004812:Epidemiologic Methods; D014943:Global Health; D006333:Heart Failure / Q000139:chemically induced* / Q000401:mortality; D006801:Humans; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D010126:Ozone / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter; D013458:Sulfur Dioxide / Q000032:analysis / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D013458:Sulfur Dioxide; D010126:Ozone; D002248:Carbon Monoxide; D009585:Nitrogen Dioxide