Effects Of Particulate Matters And Polycyclic Aromatic Hydrocarbons On Heart Rate Variability By Framingham Score

Objective： We mainly analyzed the effects of exposure to particulate matter withaerodynamic diameters≤10μm (PM₁₀) and≤2.5μm (PM_2.5) on heart rate variability （HRV）and the interaction effects of particulates and Framingham score （FRS） on decreased HRV ina panel study. To explore whether there was essential association of HRV with urinarypolycyclic aromatic hydrocarbon （PAH） mentalities and verify the effects of FRS on HRV,and further investigate possible joint effect of urinary PAH mentalities and FRS on HRV in across-sectional study.Methods: The survey and measurements were conducted in two cities-Zhuhai and Wuhan.This study population consisted of82healthy residents in Zhuhai and70healthy participantsin Wuhan. Subjects were instructed to wear the ambulatory electrocardiogram recordingssynchronizing with personal air samplers of PM₁₀and PM_2.5to continuously monitor HRVand particulates for24hours. The FRS was determined by adding up the number ofFramingham points for each risk factor such as age, low-density lipoprotein or totalcholesterol, high-density lipoprotein, blood pressure, smoker, and diabetes. The study wascomprised of1978community residents in Wuhan. We measured short-time HRV indicesusing a standard3-channel Holter monitor and determined10urinary PAH metabolites withgas chromatography-mass spectrometry.Results: After controlling for confounders, our results indicated that there was an inverserelationship between PM₁₀and HRV (P_trend=0.016and P_trend=0.018, respectively) incity-combined analyses, whereas we found no significant associations between thesevariables in city-specific analyses except in Wuhan (P_trend=0.005and P_trend=0.041, respectively). In addition, we found significant interactions between PM₁₀and FRS on TPand LF in Wuhan （for interactions, P=0.013and0.021, respectively）, and no significantinteractions between particulates and HRV in Zhuhai. The subjects with high PM₁₀in lowFRS group had greater decreased HRV than those with low PM₁₀（P=0.023for TP and P=0.004for LF）, but individuals in high FRS group did not have the significant differences. Incity-combined analyses, similar results were found. The results of cross-sectional studydemonstrated that significant correlations exist among all OH-PAHs pairwise combinations,with spearman rank correlation coefficients that ranged from0.41to0.84（P <0.0001for all）.After controlling for confounders, decreased HRV indices were significantly associated withincreased quartiles （from frist to fourth） of FRS (P_trend<0.0001for all). Individuals withincreased total concentration of urinary PAH metabolites （ΣOH-PAHs） had decreased LF(P_trend=0.008). Total concentrations of hydroxynaphthalene （ΣOHNa） was associated withSDNN (P_trend=0.013). Total concentrations of hydroxyfluorene （ΣOHFlu） also show asignificant linear trend with SDNN and LF (P_trend=0.031and P_trend=0.005, respectively). Inaddition, ΣOHNa, ΣOHFlu and FRS have a joint effect on SDNN (P_trend=0.016and P_trend=0.030). ΣOH-PAHs, ΣOHFlu and FRS combined to LF (P_trend=0.006and P_trend=0.005).Conclution: The results of panel study indicated that increased PM₁₀is associated withdecreased HRV and a interaction of PM₁₀and FRS is detrimental for HRV. Moreover, it issuggested that high FRS masks the effects of PM₁₀on HRV. The results of corss-sectionalstudy showed that increased FRS is associated with decreased the activity of cardiacautonomic function. This is the first report supporting evidence that urinary PAH metabolitesis associated with altered HRV in community residents. Moreover, there is a combined effectof urinary PAH metabolites and FRS on HRV.