Figure 2.

Associations of PM_2.5, elemental carbon, ozone (2008 Annual Averages), and distance to roadway with pulmonary vessel volumes on CT^a. Upper panes demonstrate difference in BVV (BV5, BV10, and TBV) by IQR of PM_2.5 (A), elemental carbon (B), ozone (C), and distance to roadway (D). Lower panes demonstrate difference in BV5^b by PM_2.5 (E), elemental carbon (F), ozone (G), and distance to roadway (H). ^aAll results from models adjusted for age at time of CT, sex, height, weight, smoking status, total pack-years of cigarette exposure, second-hand tobacco exposure during adulthood, personal educational attainment, occupation category, median value of owner-occupied housing, study cohort, date of CT and sine and cosine day of the year terms (to account for seasonality and time), any history of cardiovascular disease, and FEV₁. Distance to Roadway is defined as the negative natural log of distance to roadway (with higher values therefore indicating greater traffic-related pollution exposure), and those living ≥1 km from a major road were excluded. Results expressed per IQR of exposure. ^bPenalized splines demonstrating difference in BV5 as a function of air pollutant exposure. Data were fitted using a penalized spline with 3 degrees of freedom. The solid line represents adjusted difference in BV5 and the dashed lines indicate the 95% confidence interval bands. The distribution of the exposure is displayed by the rug plot along the x axis. BVV indicates blood vessel volumes; CT, computed tomography; IQR, interquartile range.