Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions

Abstract

Aims: Ambient air pollution is a major health risk, leading to respiratory and cardiovascular mortality. A recent Global Exposure Mortality Model, based on an unmatched number of cohort studies in many countries, provides new hazard ratio functions, calling for re-evaluation of the disease burden. Accordingly, we estimated excess cardiovascular mortality attributed to air pollution in Europe.

Methods and results: The new hazard ratio functions have been combined with ambient air pollution exposure data to estimate the impacts in Europe and the 28 countries of the European Union (EU-28). The annual excess mortality rate from ambient air pollution in Europe is 790 000 [95% confidence interval (95% CI) 645 000-934 000], and 659 000 (95% CI 537 000-775 000) in the EU-28. Between 40% and 80% are due to cardiovascular events, which dominate health outcomes. The upper limit includes events attributed to other non-communicable diseases, which are currently not specified. These estimates exceed recent analyses, such as the Global Burden of Disease for 2015, by more than a factor of two. We estimate that air pollution reduces the mean life expectancy in Europe by about 2.2 years with an annual, attributable per capita mortality rate in Europe of 133/100 000 per year.

Conclusion: We provide new data based on novel hazard ratio functions suggesting that the health impacts attributable to ambient air pollution in Europe are substantially higher than previously assumed, though subject to considerable uncertainty. Our results imply that replacing fossil fuels by clean, renewable energy sources could substantially reduce the loss of life expectancy from air pollution.

Keywords: Air pollution; Cardiovascular risk; Excess mortality rate; Fine particulate matter; Health promotion intervention; Loss of life expectancy.

Figure 1

Hazard ratios as a function of annual mean PM_2.5, referring to cerebrovascular disease (A) and ischaemic heart disease (B) (after ref.¹³). Solid lines show the range for which epidemiological data are available, and the dashed ones extrapolate to higher concentrations. For Global Burden of Disease 2015, the extrapolation was based on smoking studies. Shaded areas show 95% confidence intervals. CEV, cerebrovascular disease; GBD, Global Burden of Disease; GEMM, Global Exposure Mortality Model; IHD, ischaemic heart disease; PM_2.5, fine particulate matter with a diameter below 2.5 µm.

Figure 2

Regional distribution of estimated annual excess mortality rates from cardiovascular diseases (CVD = IHD + CEV) attributed to air pollution. These rates are lower limits as other non-communicable diseases are not included.

Figure 3

Estimated annual excess mortality rates attributed to air pollution in the EU-28 for lower respiratory tract infections, chronic obstructive pulmonary disease, lung cancer, cerebrovascular disease, ischaemic heart disease, and other non-communicable diseases. Bars compare results from the Global Burden of Disease (2015) and the new GEMM. CEV, cerebrovascular disease; COPD, chronic obstructive pulmonary disease; EU-28, 28 countries of the European Union; GBD, Global Burden of Disease; GEMM, Global Exposure Mortality Model; IHD, ischaemic heart disease; LC, lung cancer; LRI, lower respiratory tract infections; NCD, non-communicable diseases.

Figure 4

Estimated excess mortality attributed to air pollution in Europe, and the contributing disease categories. At least 48% are due to cardiovascular disease (ischaemic heart disease and stroke). A fraction of other non-communicable diseases should also be counted to cardiovascular diseases related mortality, with an upper limit of 32%. COPD, chronic obstructive pulmonary disease.

Figure 5

Ratio between attributable excess mortalities related to cardiovascular diseases and to respiratory diseases (including lung cancer) for different countries. The calculated ratios are lower limits as other non-communicable diseases are not included. CVD, cardiovascular diseases; RD, respiratory diseases.