Table 1.
Demographics of the study population and biologic samples for analysis of aging signature gene expression in the small airway epithelium 1
| Parameter | Healthy nonsmokers | Healthy smokers | p value 6 |
|---|---|---|---|
| n | 29 | 29 | |
| Gender (M/F) | 16/13 | 22/7 | |
| Age (yr) | 38.0 ± 12.4 | 38.8 ± 10.1 | >0.8 |
| Race (B/W/O)2 | 10/8/11 | 13/8/8 | |
| Smoking history (pack-yr) | 0 | 17.8 ± 8.4 | |
| Urine nicotine (ng/ml) | negative | 1657 ± 1527 | |
| Urine cotinine (ng/ml) | negative | 1929 ± 1060 | |
| Pulmonary function parameters3 | |||
| FVC | 106.9 ± 12.1 | 111.1 ± 11.6 | >0.17 |
| FEV1 | 106.3 ± 12.2 | 109.4 ± 13.1 | >0.35 |
| FEV1/FVC | 82.8 ± 4.9 | 81.0 ± 4.3 | >0.13 |
| TLC | 99.7 ± 17.3 | 97.6 ± 14.1 | >0.6 |
| DLCO | 90.4 ± 9.6 | 86.0 ± 5.4 | <0.04 |
| Body mass index (BMI) | 26.4 ± 5.3 | 27.8 ± 4.8 | >0.3 |
| Epithelial cells4 | |||
| % epithelial cells | 98.9 ± 0.9 | 99.2 ± 0.8 | >0.2 |
| % inflammatory cells | 1.0 ± 0.8 | 0.8 ± 0.8 | >0.2 |
| Differential cell count5 | |||
| Ciliated (%) | 71.3 ± 5.3 | 62.9 ± 6.9 | <0.00001 |
| Secretory (%) | 10.0 ± 4.5 | 12.3 ± 6.4 | >0.12 |
| Basal (%) | 9.5 ± 6.6 | 9.6 ± 6.6 | >0.96 |
| Undifferentiated columnar (%) | 8.2 ± 4.9 | 14.5 ± 8.2 | <0.001 |
1Data is presented as mean ± standard deviation.
2B = Black, W = White, O = Other.
3Pulmonary function testing parameters are given as % predicted value with the exception of FEV1/FVC, which is reported as % observed; FVC – forced vital capacity, FEV1 – forced expiratory volume in 1 sec. FVC, FEV1 and FEV1/FVC are post-bronchodilator values. TLC – total lung capacity, DLCO – diffusing capacity of the lung for carbon monoxide.
4Small airway epithelium.
5As % of small airway epithelium recovered.
6Smoker vs Nonsmoker comparison by student’s t-test with p < 0.05 being significant.