Dynamic association of ambient air pollution with incidence and mortality of pulmonary hypertension: A multistate trajectory analysis

BACKGROUND: There is little evidence regarding the association between ambient air pollution and incidence and the mortality of pulmonary hypertension (PH). METHODS: We included 494,750 participants at baseline in the UK Biobank study. Exposures to PM(2.5), PM(10), NO(2), and NO(x) were estimated at geocoded participants' residential addresses, utilizing pollution data provided by UK Department for Environment, Food and Rural Affairs (DEFRA). The outcomes were the incidence and mortality of PH. We used multivariate multistate models to investigate the impacts of various ambient air pollutants on both incidence and mortality of PH. RESULTS: During a median follow-up of 11.75 years, 2517 participants developed incident PH, and 696 died. We observed that all ambient air pollutants were associated with increased incidence of PH with different magnitudes, with adjusted hazard ratios (HRs) [95% confidence intervals (95% CIs)] for each interquartile range (IQR) increase of 1.73 (1.65, 1.81) for PM(2.5), 1.70 (1.63, 1.78) for PM(10), 1.42 (1.37, 1.48) for NO(2), and 1.35 (1.31, 1.40) for NO(x). Furthermore, PM(2.5), PM(10), NO(2) and NO(2) influenced the transition from PH to death, and the corresponding HRs (95% CIs) were 1.35 (1.25, 1.45), 1.31 (1.21, 1.41), 1.28 (1.20, 1.37) and 1.24 (1.17, 1.32), respectively. CONCLUSION: The results of our study indicate that exposure to various ambient air pollutants might play key but differential roles in both the incidence and mortality of PH.