Associations between main ambient air pollutants and ischaemic heart disease risk in the UK biobank: A prospective cohort study

Abstract

Objectives

Air pollutants have been associated with multiple cardiovascular diseases, but evidence on the long-term and combined effects of air pollutants on the incidence of ischaemic heart disease (IHD) remains limited.

Study design

Prospective cohort study.

Methods

A total of 398,547 participants from the UK Biobank were included in this prospective cohort study. Concentrations of air pollutants were calculated using the Land Use Regression (LUR) model, including particulate matter (PM) [PM_2.5, PM_10-2.5, PM₁₀] and nitrogen oxides (NO_x and NO₂). Cox proportional hazards models and restricted cubic spline models were utilised to detect associations between air pollutants and IHD incidence. A novel air pollution score was proposed to indicate the synergistic effect of five air pollutants by combining variance contribution and eigenvalue of each pollutant in principal components analysis (PCA).

Results

In a median follow-up of 12.5 years, 23,721 of 398,547 participants were diagnosed with IHD. For every 1-μg/m³ increase, the risk of IHD was 1.026 (95 % confidence interval [CI]: 1.012–1.040) and 1.002 (95 % CI: 1.001–1.003) for PM_2.5 and NO_x, respectively. This study found that for every increase in quartile of PM_2.5 level, the hazard ratios (HRs) for IHD were 1.035 (95 % CI: 0.998–1.073), 1.043 (95 % CI: 1.005–1.082) and 1. 063 (95 % CI: 1.022–1.106) compared with the lowest quartile. Long-term estimated exposure to multiple air pollutants showed a significant association with elevated risk of IHD (HRs = 1.029, 95 % CI: 1.007–1.051) and the exposure-response curve was linear.

Conclusions

Among UK adults, long-term and synchronous exposure to multiple air contaminants was associated with an increased risk of IHD.