Table 1. Baseline Characteristics and Comorbidities According to PM2.5 Quartilea.
| Characteristic | Quartile 1 (PM2.5 range, 9.13-10.07 μg/m3) (n = 7856) | Quartile 2 (PM2.5 range, 10.07-10.52 μg/m3) (n = 7915) | Quartile 3 (PM2.5 range, 10.52-11.11 μg/m3) (n = 7847) | Quartile 4 (PM2.5 range, 11.11-15.74 μg/m3) (n = 7796) |
|---|---|---|---|---|
| Age, median (IQR), y | 76.6 (66.2-84.4) | 77.7 (67.4-85.0) | 76.9 (65.3-84.4) | 76.6 (64.6-85.0) |
| Female sex | 3616 (46.0) | 3968 (50.1) | 4038 (51.5) | 4191 (53.8) |
| Black race | 75 (1.0) | 330 (4.2) | 936 (11.9) | 1572 (20.2) |
| Heart failure | 3935 (50.1) | 4350 (55.0) | 4613 (58.8) | 4850 (62.2) |
| Hypertension | 6144 (78.2) | 6363 (80.4) | 6497 (82.8) | 6618 (84.9) |
| Diabetes | 2089 (26.6) | 2432 (30.7) | 2645 (33.7) | 2845 (36.5) |
| CAD | 3002 (38.2) | 3310 (41.8) | 3545 (45.2) | 3800 (48.7) |
| PAD | 831 (10.6) | 982 (12.4) | 1081 (13.8) | 1238 (15.9) |
| TIA | 219 (2.8) | 255 (3.2) | 248 (3.2) | 235 (3.0) |
| Social factors, median (IQR)b | ||||
| Annual household income, $ | 78 021 (58 913-96 510) | 56 069 (46 132-73 588) | 44 319 (35 873-56 148) | 33 166 (25 467-43 386) |
| Some college attendance, % | 14.8 (10.4-18.1) | 16.5 (12.7-21.2) | 18.4 (12.6-23.9) | 18.4 (11.8-24.5) |
| High school diploma, % | 23.7 (16.6-30.8) | 28.4 (22.9-37.5) | 30.5 (21.2-39.1) | 31.3 (19.5-39.1) |
Abbreviations: CAD, coronary artery disease; IQR, interquartile range; PAD, peripheral arterial disease; PM2.5, particulate matter measuring 2.5 μm or less; TIA, transient ischemic attack.
a
Data are presented as number (percentage) of participants unless otherwise indicated.
b
Social factors derived from estimates obtained by the US Census Bureau.33