Table 1.
Descriptive characteristics (mean ± SD or %) of study participants.
| Characteristic | Emphysema cohort | Lung function cohort | ||
|---|---|---|---|---|
| 1-year estimate(n= 6,515) | 20-year estimate(n = 4,813) | 1-year estimate(n = 3,791) | 20-year estimate(n = 2,811) | |
| Percent emphysema (%), –910 HU | 19.9 ± 13.4 | 20.5 ± 13.6 | 20.2 ± 13.3 | 20.7 ± 13.5 |
| Airflow limitation (%)a | 5.7 | 5.8 | 5.9 | 5.9 |
| Percent predicted FEV1 | 93.9 ± 17.8 | 93.5 ± 18.1 | 93.8 ± 17.9 | 93.4 ± 18.2 |
| Percent predicted FVC | 95.5 ± 16.2 | 95.2 ± 16.3 | 95.4 ± 16.2 | 95.2 ± 16.3 |
| Percent predicted FEV1/FVC | 98.5 ± 10.7 | 98.4 ± 10.9 | 98.4 ± 10.7 | 98.3 ± 10.9 |
| FEV1 (L) | 2.4 ± 0.7 | 2.4 ± 0.7 | 2.4 ± 0.7 | 2.4 ± 0.7 |
| FVC (L) | 3.2 ± 1.0 | 3.2 ± 1.0 | 3.2 ± 1.0 | 3.2 ± 1.0 |
| FEV1/FVC (%) | 75.1 ± 8.5 | 75.0 ± 8.7 | 75.0 ± 8.5 | 74.9 ± 8.6 |
| Age (years) | 62 ± 10 | 62 ± 10 | 61 ± 10 | 62 ± 10 |
| Female (%) | 54 | 53 | 51 | 50 |
| Race/ethnicity (%) | ||||
| White | 37 | 43 | 36 | 39 |
| Black | 28 | 30 | 24 | 28 |
| Chinese | 11 | 7 | 15 | 10 |
| Hispanic | 24 | 21 | 25 | 22 |
| Education (%) | ||||
| Less than high school | 17 | 15 | 18 | 15 |
| High school | 18 | 19 | 17 | 19 |
| Higher education | 47 | 47 | 46 | 46 |
| Advanced degree | 18 | 19 | 19 | 20 |
| Any smoke exposure (%) | 48 | 50 | 46 | 49 |
| Smoking status (%) | ||||
| Never | 51 | 49 | 48 | 46 |
| Former | 36 | 38 | 42 | 44 |
| Current | 13 | 13 | 10 | 10 |
| Pack-years of smoking (%) | ||||
| 0 | 52 | 50 | 54 | 52 |
| ≤ 10 | 19 | 19 | 16 | 15 |
| > 10 and ≤ 20 | 10 | 10 | 9 | 9 |
| > 20 | 20 | 21 | 21 | 23 |
| Residential stability (years) | ||||
| ≥ 10 | 69 | 75 | 68 | 75 |
| ≥ 20 | 45 | 52 | 44 | 51 |
| Study site (%) | ||||
| Winston-Salem, NC | 15 | 17 | 13 | 15 |
| New York, NY | 18 | 16 | 23 | 19 |
| Baltimore, MD | 14 | 16 | 11 | 14 |
| St. Paul, MN | 15 | 17 | 13 | 15 |
| Chicago, IL | 18 | 18 | 18 | 19 |
| Los Angeles, CA | 20 | 16 | 23 | 17 |
| Air pollution | ||||
| PM2.5 (μg/m3) | 16.3 ± 3.7 | 22.0 ± 5.0 | 14.2 ± 2.4 | 22.2 ± 5.0 |
| PM10 (μg/m3) | NA | 34.3 ± 7.7 | NA | 34.7 ± 7.7 |
| NOx (ppb) | 48.3 ± 25.2 | NA | 41.1 ± 21.1 | NA |
| NA, not applicable. aAir flow restriction defined as an FEV1/FVC and FEV1 less than the lower limit of normal (LLN). | ||||