Ambient Fine Particulate Matter Exposure and Blood Pressure: Evidence from a Large Chinese Multiple Follow-Up Study.

Objective:This study aimed to investigate the association of ambient PM2.5 exposure with blood pressure (BP) at the population level in China. Methods:A total of 14,080 participants who had at least two valid blood pressure records were selected from the China Health and Retirement Longitudinal Survey during 2011-2015. Their long-term PM2.5 exposure was assessed at the geographical level, on the basis of a regular 0.1° × 0.1° grid over China. A mixed-effects regression model was used to assess associations. Results:Each decrease of 10 μg/m3 in the 1 year-mean PM2.5 concentration (FPM1Y) was associated with a decrease of 1.24 [95% confidence interval (CI): 0.84-1.64] mmHg systolic BP (SBP) and 0.50 (95% CI: 0.25-0.75) mmHg diastolic BP (DBP), respectively. A robust association was observed between the long-term decrease in PM2.5 and decreased BP in the middle-aged and older population. Using a generalized additive mixed model, we further found that SBP increased nonlinearly overall with FPM1Y but in an approximately linear range when the FPM1Y concentration was < 70 µg/m3; In contrast, DBP increased approximately linearly without a clear threshold. Conclusion:Efficient control of PM2.5 air pollution may promote vascular health in China. Our study provides robust scientific support for making the related air pollution control policies.