Comparison of characteristics measured at CARDIA Y10 (mean age of 35 years) between the groups with and without rapid FEV1 decline (over subsequent 10 years)
| Characteristics at Y10 | Rapid FEV1 decline (n=754) | Non-rapid FEV1 decline (n=1504) | p Value |
| Age (in years) | 35.3±3.7 | 34.8±3.6 | 0.001 |
| Male | 49.9% | 41.1% | <0.001 |
| Black race | 45.8% | 42.5% | 0.15 |
| Body mass index (kg/m2) | 26.3±5.3 | 26.1±5.4 | 0.46 |
| Low socioeconomic status | 41.0% | 35.7% | 0.01 |
| Education (in years) | 14.5±2.3 | 15.2±2.5 | <0.001 |
| Never smokers | 59.6% | 64.6% | 0.02 |
| Pack-years | 3.7±6.8 | 2.7±5.7 | <0.001 |
| Self-reported low level of physical activity | 19.0% | 19.0% | 1.00 |
| Family history of diabetes mellitus | 24.0% | 27.8% | 0.04 |
| Baseline FEV1 (in millilitersmL) | 3630±790 | 3400±760 | <0.001 |
| Percent predicted FEV1 | 102.3±12.3 | 98.9±11.8 | <0.001 |
| Baseline FVC (in millilitersmL) | 4520±1020 | 4200±1000 | <0.001 |
| Percent predicted FVC | 100.5±13.8 | 96.4±13.2 | <0.001 |
| Baseline FEV1/FVC | 82±6 | 82±6 | 0.48 |
| Metabolic syndrome | 0% | 0% | 1.00 |
| Large waist circumference | 13.2% | 13.3% | 1.00 |
| High plasma triglyceride | 5.8% | 7.3% | 0.22 |
| Low plasma HDL cholesterol | 29.7% | 31.3% | 0.44 |
| Hypertension | 11.4% | 6.2% | 0.001 |
| Elevated serum glucose | 0.8% | 1.0% | 0.82 |
Note 1: Definitions: Rapid FEV1 decline group is the tertile with greatest decline in FEV1 between CARDIA Y10 and Y20 and the rest constitute the non-rapid decline group; low socioeconomic status is defined by total combined family income <$35 000 in the prior year; low-level of physical activity was self-reported as level 1 or 2 in a five-item questionnaire that compared individuals to others in the same age and sex; metabolic syndrome and its components are defined in the online data supplementary file 1. Family history of diabetes mellitus was defined by self-report of presence of diabetes mellitus in any first degree relative.
CARDIA, Coronary Artery Risk Development in Young Adults; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; HDL, high-density lipoprotein.