Long-Term Exposure to Fine Particulate Matter and Hypertension Incidence in China

The risk of incident hypertension associated with long-term exposure to fine particulate matter (PM_2.5) was still unclear by studies conducted in North America and Europe, and this relationship has rarely been quantified at higher ambient concentrations typically found in developing countries. We aimed to investigate the association between PM_2.5 and incident hypertension using the large-scale prospective cohorts in China. We included 59 456 participants without hypertension aged ≥18 years from the China-PAR (Prediction for Atherosclerotic Cardiovascular Disease Risk in China) project. Data on ambient PM_2.5 at participants' residential address were obtained during 2004 to 2015 using a satellite-based spatial-temporal model. Hazard ratios and 95% CIs were calculated for incident hypertension using stratified Cox proportional hazards models with adjustment of potential confounders. The findings indicated that average PM_2.5 concentration from 2004 to 2015 at study participants' address was 77.7 μg/m³. During the follow-up of 364 947 person-years, we identified 13 981 incident hypertension cases. Compared with the lowest quartile exposure of PM_2.5, participants in the highest quartile had an increased risk of incident hypertension with a hazard ratio (95% CI) of 1.77 (1.56-2.00). Each 10 μg/m³ increment of PM_2.5 concentration could increase 11% risk of hypertension (hazard ratio, 1.11; 95% CI, 1.05-1.17). This cohort study provided the first evidence from China that long-term exposure to PM_2.5 was independently associated with incident hypertension at relatively high ambient concentrations. Stringent strategies on PM_2.5 pollution control are warranted to improve the air quality and contribute to the reduction of disease burden of hypertension in China.