Short-term ambient particulate air pollution exposure, microRNAs, blood pressure and lung function

Ambient particulate air pollution is a risk factor for cardiovascular and respiratory disease, yet the biological mechanisms underlying this association are not well understood. The current study aimed to investigate the mediation role of microRNAs on the association between personal PM_2.5 exposure and blood pressure and lung function. One hundred and twenty adults (60 truck drivers and 60 office workers) aged 18-46 years were assessed on the June 15, 2008 and at follow-up (1- to 2-weeks later). MicroRNAs were extracted from the peripheral blood samples. Compared to truck drivers, there is a significant increase in FEF_25-75, FEV₁, and FEV₁/FVC and a decrease in PM_2.5 in office workers (all p < 0.05). According to the Bonferroni corrected threshold p-value < 6.81 × 10^-5 (0.05/734) used, personal PM_2.5 data showed a significant positive association with miR-644 after the adjustment for age, BMI, smoking status, and habitual alcohol use. The mediation effect of miR-644 on the association between personal PM_2.5 exposure and FEF_25-75 [B (95%CI) = -1.342 (-2.810, -0.113)], PEF [B (95%CI) = -1.793 (-3.926, -0.195)], and FEV₁/FVC [B (95%CI) = -0.119‰ (-0.224‰, -0.026‰)] was significant only for truck drivers after the adjustment for covariates. There were no similar associations with blood pressure. These results demonstrate microRNAs to potentially mediate association of PM_2.5 with lung function. Subsequent studies are needed to further elucidate the potential mechanisms of action by which the mediation effect of microRNAs is achieved with this process.