Association between occupational noise exposure duration and heart rate variability among Chinese adults: The role of plasma miRNAs.

We aimed to explore the association between occupational noise exposure duration and heart rate variability (HRV) and the underlying mechanism. A total of 449 subjects in a manufacturing company in Wuhan, China were included in our study and six candidate miRNAs (miR-200a-3p, miR-200b-3p, miR-200c-3p, miR-1-3p, miR-92a-3p and miR-21-5p) were tested among 200 individuals. Information combining the work histories and the occupational noise monitoring records were used to calculate the exposure of occupational noise, HRV indices were measured by using 3-channel digital Holter monitors, including the standard deviation of all normal R-R intervals (SDNN), the root mean of the square of successive differences between adjacent normal NN intervals (r-MSSD), SDNN index, low-frequency power (LF), high-frequency power (HF) and TP (total power). We found a significant linear negative dose-response relationship between occupational noise exposure duration and HRV indices (P for overall <0.05, P for nonlinear >0.05), including SDNN, r-MSSD, SDNN index, LF and HF. In the continuous models, the β (95% CIs) for each 1-year occupational noise exposure were -0.002 (-0.004, -0.001) for SDNN, -0.002 (-0.004, -0.001) for r-MSSD, -0.002 (-0.004, -0.001) for SDNN index, and -0.006 (-0.012, -0.001) for HF. Meanwhile, we also found that occupational noise exposure duration was significantly associated with lower expression of five miRNAs, when adjusting for other covariates. The β (95% CIs) were -0.039 (-0.067, -0.011) for miRNA-200c-3p, -0.053 (-0.083, -0.022) for miRNA-200a-3p, -0.044 (-0.070, -0.019) for miRNA-200b-3p, -0.032 (-0.048, -0.017) for miRNA-92a-3p, and -0.063 (-0.089, -0.038) for miRNA-21-5p in the continuous models. In addition, we found a positive association between miRNA-1-3p and LF (β = 0.039, 95% CI = 0.002, 0.080). Our study suggests that occupational noise exposure duration is associated with cardiac autonomic dysfunction, and the role of miRNAs in noise induced HRV reduction needs to be confirmed in future studies.