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.

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/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.

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.

Figure 1

Association between (A) gaseous and (B) particulate air pollutants and heart failure hospitalisation or heart failure mortality ppm=parts per million. ppb=parts per billion.

Figure 2

Additional analysis across all gaseous and particulate air pollutants *Kwon et al provided separate estimates for all age groups and for people older than 75 years. This study therefore appears twice in the additional analysis when stratified by age. For the overall analysis, we have used the estimates provided for all age groups. †Kwon and Peel et al provided separate estimates stratified by study design and therefore appear twice in the additional analysis. For the overall analysis, we have used the estimates provided for the time-series study design. ppm=parts per million. ppb=parts per billion.

Figure 3

Median daily PM_2·5 concentrations and estimated impact of a reduction in PM_2·5 to a target concentration on heart failure hospitalisation per US state Heart failure hospitalisation rates were not available for 15 states (appendix); data not shown for Mississippi (median daily PM_2·5 13·4 μg/m³; annual reduction in heart failure hospitalisations 15 per 100 000). US state abbreviations are defined in the appendix.