Ambient PM_2.5 and Its Components Associated with Dynamic Progression from Different Blood Pressure States to...

The relationships between fine particulate matter (PM_2.5) and the risk of hypertension (HTN) and cardiovascular disease (CVD) have been well documented. However, the associations between specific chemical constituents of PM_2.5 and the dynamic progression of hypertensive CVD remain unclear. Using multistate models and mediation analyses in a cohort of 316,087 individuals, we investigated the associations between PM_2.5, PM_2.5 chemical components (sulfate [SO₄ ^2-], nitrate [NO₃ ^-], ammonium [NH₄ ⁺], organic matter [OM], and black carbon [BC]), and the dynamic progression from different blood pressure states to incident CVD and mortality. Our findings revealed that PM_2.5 and its constituents were positively associated with the dynamic HTN progression. For example, with each interquartile range (IQR) increase, PM_2.5, SO₄ ^2-, NO₃ ^-, NH₄ ⁺, OM, and BC were significantly associated with the disease transition from prehypertension (pre-HTN) to HTN, with hazard ratios (HRs) of 1.116 (95% confidence interval [CI]: 1.104-1.128), 1.186 (95% CI: 1.171-1.202), 1.179 (95% CI: 1.166-1.193), 1.171 (95% CI: 1.159-1.184), 1.155 (95% CI: 1.141-1.169), and 1.147 (95% CI: 1.133-1.161), respectively. Mediation analysis demonstrated that pre-HTN and HTN significantly mediated the relationships between PM_2.5, PM_2.5 components, and the increased risk of CVD and cardiovascular mortality. This study provides evidence that ambient PM_2.5 and its chemical constituents may be important determinants in the dynamic progression of HTN. Controlling exposure to PM_2.5 and its components, particularly during the pre-HTN phase, could be an effective strategy to curb the development of hypertensive CVD and alleviate its public health impact.