Global association of air pollution and heart failure: a systematic review and meta-analysis

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. FINDINGS: 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/m³, 95% CI 1·42–2·82; PM₁₀ 1·63% per 10 μg/m³, 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/m³ would prevent 7978 heart failure hospitalisations and save a third of a billion US dollars a year. INTERPRETATION: 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. FUNDING: British Heart Foundation.