Long-term Exposure To Fine Particulate Matter Components And Prevalence Of Subclinical Atherosclerosis In The Multi-Ethnic Study Of Atherosclerosis

Background. Concentrations of outdoor fine particulate matter (PM2.5) have been associated with cardiovascular disease. Effects of exposure to PM2.5may be due to PM chemical composition.Methods. Using data from the Multi-Ethnic Study of Atherosclerosis (MESA) collected at baseline (2000-2002), cross-sectional associations of PM2.5and PM2.5components (elemental carbon [EC], organic carbon [OC], silicon and sulfur) with measures of subclinical atherosclerosis (coronary artery calcium [CAC] and carotid intima-media thickness [CIMT]) were investigated in6,256US adults without clinical cardiovascular disease. PM component exposures were estimated in three ways using MESA fixed monitoring data:(1) nearest monitor (the primary approach);(2) inverse-distance monitor weighting (IDW); and (3) city-wide average.Results. Using the exposure estimate based on nearest monitor, CIMT was positively associated with OC, but not with PM2.5total mass, EC, silicon or sulfur. Other associations were also seen with some of the other approaches to estimating exposure, especially for Silicon, although these were not entirely consistent. None of the PM measures were associated with either the presence or extent of CAC. In sensitivity analyses, some findings were sensitive to control for sonographerConclusion. Of the PM2.5components, only OC was associated with increased CIMT; OC was also associated with CIMT using secondary approaches to estimating exposure. PM2.5chemical composition may be important in determining the effect of PM exposure on atherosclerosis.