Table 1.
Baseline characteristics of the Atherosclerosis Risk in Communities study population, stratified above and below site-specific median annual average PM2.5 concentration
| Characteristic | Annual Average PM2.5 (μg/m3) | |
|---|---|---|
| ≤Site-Specific Median | >Site-Specific Median | |
| Number of participants | 5499 | 5498 |
| Age, mean (SD), yr | 63 (6) | 63 (6) |
| Female, n | 3033 (55%) | 3128 (57%) |
| Black, n | 1177 (21%) | 1231 (22%) |
| Smoker, n | ||
| Never | 2332 (43%) | 2211 (41%) |
| Former | 2362 (43%) | 2420 (44%) |
| Current | 790 (14%) | 822 (15%) |
| eGFR, mean (SD), ml/min per 1.73 m2 | 86 (16) | 86 (16) |
| eGFR<60 ml/min per 1.73 m2, n | 346 (6%) | 349 (6%) |
| UACR, median (IQR), mg/g | 3.4 (5.8) | 4.0 (6.4) |
| C-reactive protein, median (IQR), mg/L | 2.5 (4.4) | 2.5 (4.4) |
| Body mass index, mean (SD), kg/m2 | 28.8 (5.5) | 28.8 (5.7) |
| Systolic BP, mean (SD), mm Hg | 127 (19) | 128 (19) |
| Hypertension, n | 2546 (46%) | 2678 (49%) |
| Diabetes mellitus, n | 872 (16%) | 943 (17%) |
| Composite cardiovascular disease, n | 1026 (19%) | 1090 (20%) |
| Neighborhood socioeconomic score (SD) | 0.4 (5.4) | −0.3 (5.5) |
| Annual household income, n | ||
| <$25,000 | 1591 (30%) | 1699 (32%) |
| ≥$25,000 | 3676 (68%) | 3536 (66%) |
| Refused | 124 (2%) | 126 (2%) |
| Education, n | ||
| ≤11 yr | 1045 (19%) | 1042 (19%) |
| 12–16 yr | 2273 (41%) | 2358 (43%) |
| 17–21 yr | 2171 (40%) | 2091 (38%) |
| Temperature, mean (SD), °C | 12.4 (4.3) | 13.0 (4.0) |
Median annual average PM2.5 concentration for each site: Forsyth County, 15.3 μg/m3; Jackson, 12.2 μg/m3; Minneapolis, 9.4 μg/m3; and Washington County, 14.6 μg/m3. PM2.5, particulate matter <2.5 μm in aerodynamic diameter; UACR, urinary albumin-creatinine ratio; IQR, interquartile range.