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 ¦Ìm [PM2¡¤5] or <10 ¦Ìm [PM10]) air pollutants, and heart failure hospitalisations or heart failure mortality. We used a random-effects model to derive overall risk estimates per pollutant.
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 ¦Ìg/m3, 95 % CI 1¡¤42-2¡¤82; PM10 1¡¤63 % per 10 ¦Ìg/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 ¦Ìg/m3 would prevent 7978 heart failure hospitalisations and save a third of a billion US dollars a year.
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.
British Heart Foundation.