Association Between Habitation Altitude,Ambient Air Pollution With Left Ventricular Structure And Diastolic Function

Background and objectiveFew studies have found a detectable adverse association between habitation altitude,air pollutants with cardiac imaging phenotypes in asymptomatic individuals,however,little studies were reported about the influence based on a large-scale population from a nationwide study.The aim of this study is to explore the association of long-term exposure to different altitude habitats,ambient air pollution(PM2.5 and PM10)with LV structure and LVDD among a large-scale free-living population.MethodsData of Part ? from two large-scale cross-sectional studies which were conducted with similar investigation method and items,including the China Hypertension Survey(CHS)and the chronic cardiopulmonary disease survey in Xinjiang and Tibet area of China.A total of 34,215 residents were eligible and recruited in the study.24,401 participants were selected only from the CHS in Part ? to explore the impact of PM2.5 and PM10 due to the bias of air pollutant concentration measurements in Xinjiang and Tibet.The clinical evaluation of left ventricular function based on echocardiography,and all experienced echocardiographers were trained using the protocol.Defined and evaluated left ventricular diastolic dysfunction(LVDD)according to the 2009 American Society of Echocardiography(ASE)guidelines.Altitude of each survey sites were estimated from 2400 homogenized surface stations,and was divided into low(<1,500m),middle(1,500-3,500m)and high(?3,500m)level groups.The air pollutants annual average concentrations of the survey year for each participant was divided into three levels according to the tertiles of the value.ResultsPart ?:Among the 34,215 participants(55.87 years,male 45.92%;altitude ranging 3.1?4,507 m),weighted LVDD prevalence was 37.84%,and 35.19%,1.29%,1.36%were diagnosed as Grade ??? LVDD,respectively.After adjusted the various confounding factors,negative linear association were found between left ventricular end-diastolic diameter(LVEDD),left atrial diameter(LA diameter),interventricular septum thickness(IVSD),left ventricular mass index(LVMI)and habitation altitude.With per 500-meter altitude increment,the estimation(95%CI)of LVEDD and LVMI were-0.34(-0.36--0.31)and-1.39(-1.51--1.27),respectively.Compared with low level group,the ORs(95%CI)of LVDD for middle and high level group were 1.95(1.77-2.14)and 2.22(1.91-2.57),respectively(Ptrend<0.001).There was a nonlinear relationship(upwards sloping "W" shape,Pnon-linear<0.001)between altitude and the risk of LVDD assessed the restricted cubic spline(RCS).Moreover,the results were also similar in stratified and sensitivity analyses.Part ?:The mean age of participants was 56.4 years,46.53%were male.After adjusted the various confounding factors,positive linear association were found between left ventricular end-systolic diameter(LVESD),IVSD,left ventricular posterior wall thickness(LVPWD),relative wall thickness(RWT),LVMI and PM2.5 or PM10 concentration.With per 10?g/m3 increment of PM2.5 and PM10,the estimation(95%CI)of LVMI was 1.52(0.86-2.19)and 2.23(1.92-2.54).The ORs(95%CI)for LVDD in the fully adjusted model were 1.25(1.15-1.37)and 2.25(1.98-2.54)for the participants in the middle and worst third level of PM2.5 condition when compared to the best third group,respectively.There was a 58%(95%CI:51%-66%)elevated LVDD risk with per 10?g/m3 increment.There was a "J" shape concentration-response relationship between annual average ambient PM2.5 with the LVDD risk assessed the RCS(Pnon-liner<0.001).The LVDD risk(95%CI)was 0.89(0.87-0.91)for per 10?g/m3 PM10 increment.Although there was a positive linear association between PM10 and LVDD risk around 70-120?g/m3,the overall LVDD risk was tend to downward when assessed the RCS.Moreover,the results were also similar in stratified and sensitivity analyses.ConclusionsElevated habitation probable lead to LV myocardial remodeling,and represents decreased LV volume and LVMI.Higher altitude is associated with increased risk of LVDD among people living over 1,500m.The significantly association between ambient PM2.5 and PM10 concentration with LV hypertrophy,enlargement was demonstrated in the current study.And the risk of LVDD was significantly influenced by elevated PM2.5 instead of PM10.