Table 2. Airflow Obstruction at Years 0 and 20.
| Airflow Obstruction | Present | Absent | Present | Absent |
|---|---|---|---|---|
| Year 0 | Year 20 | |||
| Number (%) | 173 (6.9%) | 2323 (93.1%) | 195 (7.8%) | 2301 (92.2%) |
| Age – years | 25.5 (0.3) | 25.0 (0.1) | 45.0 (0.3) | 45.3 (0.1) |
| Male – number (%) | 95 (54.9%) | 1039 (44.7%)† | 89 (45.6%) | 1045 (45.4%) |
| White – number (%) | 103 (59.5%) | 1316 (56.7%) | 121 (62.1%) | 1298 (56.4%) |
| Education > high school - number (%) | 102 (59.0%) | 1575 (67.8%)* | 140 (71.8%) | 1793 (77.9%)* |
| BMI1- kg/m2 | 24.3 (0.3) | 24.4 (0.1) | 26.9 (0.4) | 29.3 (0.1)§ |
| Smoking – current / previous / never (%)2 | 39.9/ 13.3 / 46.8 | 23.9 / 14.5 / 61.6§ | 34.6 / 23.0 / 42.4 | 16.7 / 19.2 / 64.1§ |
| Exposure to second hand smoke (%)3 | 166 (96.0%) | 2118 (95.5%) | 107 (54.9%) | 1082 (47.2%)* |
| FEV1 % predicted | 88.7 (0.9) | 99.6 (0.2)§ | 82.5 (1.1) | 96.3 (0.3)§ |
| FVC % predicted | 106.1 (1.0) | 100.3 (0.2)§ | 100.0 (1.1) | 96.3 (0.3)† |
| FEV1/FVC | 0.71 (0.00) | 0.85 (0.00)§ | 0.66 (0.00) | 0.80 (0.01)§ |
| COPD self-reported – number (%) | 9 (5.2%) | 45 (1.9%)* | 14 (7.2%) | 36 (1.6%)§ |
The results are mean (SE) unless otherwise noted. There are 2,496 participants.
Airflow obstruction is defined as FEV1/FVC < age, race, sex specific lower limit of normal [24]; specifics in text.
Comparisons made between airflow obstruction present and absent groups using chi-square tests for categorical variables and t-tests for continuous variables.
*
p < 0.05
†
p < 0.01
‡
p < 0.001
§
p < 0.0001