Long-Term Exposure to Airborne Particles and Arterial Stiffness: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND: Increased arterial stiffness could represent an intermediate subclinical outcome in the mechanistic pathway underlying associations between average long-term pollution exposure and cardiovascular events. OBJECTIVE: We hypothesized that 20 years of exposure to particulate matter (PM) <= 2.5 and 10 mu m in aerodynamic diameter (PM2.5 and PM10, respectively) would be positively associated with arterial stiffness in 3,996 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) who were seen at six U. S. study sites. METHODS: We assigned pollution exposure during two decades preceding a clinical exam (2000-2002) using observed PM10 from monitors nearest participants' residences and PM10 and PM2.5 imputed from a space-time model. We examined three log-transformed arterial stiffness outcome measures: Young's modulus (YM) from carotid artery ultrasound and large (C-1) and small (C-2) artery vessel compliance from the radial artery pulse wave. All associations are expressed per 10 mu g/m(3) increment in PM and were adjusted for weather, age, sex, race, glucose, triglycerides, diabetes, waist: hip ratio, seated mean arterial pressure, smoking status, pack-years, cigarettes per day, environmental tobacco smoke, and physical activity. C-1 and C-2 models were further adjusted for heart rate, weight, and height. RESULTS: Long-term average particle exposure was not associated with greater arterial stiffness measured by YM, C-1, or C-2, and the few associations observed were not robust across metrics and adjustment schemes. CONCLUSIONS: Long-term particle mass exposure did not appear to be associated with greater arterial stiffness in this study sample.