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 μm in aerodynamic diameter (PM(2.5) and PM(10), 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 PM(10) from monitors nearest participants’ residences and PM(10) and PM(2.5) 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 μg/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.