Table 1.
Comparison of Selected Lung Function Trajectory Groups among Young Smokers (40–50 yr of Age) in the Lovelace Smokers’ Cohort (N = 222)
| Characteristics | ND |
RD |
P Value | ||
|---|---|---|---|---|---|
| High LF (n = 40) | Low LF (n = 70) | High LF (n = 68) | Low LF (n = 44) | ||
| Age, yr | 44.6 ± 3.2 | 45.4 ± 3.9 | 44.8 ± 3.1 | 46.7 ± 3.2 | 0.03 |
| Male | 10 (25) | 21 (30) | 18 (26.5) | 7 (15.9) | 0.26 |
| Hispanic | 15 (37.5) | 21 (30) | 16 (23.5) | 6 (13.6) | 0.01 |
| BMI, kg/m2 | 27.6 ± 6.3 | 30.6 ± 8 | 26.9 ± 5.2 | 27.2 ± 6.4 | 0.13 |
| Education, ≥HS | 23 (57.5) | 47 (67.1) | 54 (79.4) | 23 (52.3) | 0.92 |
| Current smoker | 30 (75) | 56 (80) | 45 (66.2) | 34 (77.3) | 0.56 |
| Pack-year | 30.2 ± 13.7 | 34.5 ± 15.8 | 28 ± 10.2 | 36.9 ± 16.4 | 0.34 |
| Exposure to fumes | 14 (35) | 19 (27.5) | 19 (27.9) | 14 (32.6) | 0.87 |
| Exposure to dust | 6 (15) | 6 (8.7) | 5 (7.4) | 9 (20.9) | 0.48 |
| Wood smoke exposure | 10 (25.6) | 20 (29) | 19 (28.4) | 16 (37.2) | 0.31 |
| Follow-up, yr | 4.1 ± 2.1 | 4.2 ± 2.4 | 4.3 ± 2.5 | 3.3 ± 2.3 | 0.19 |
| Visits, n | 4 ± 1.4 | 4 ± 1.5 | 4 ± 1.5 | 3 ± 1.3 | 0.06 |
| FEV1, L | 3.5 ± 0.7 | 2.5 ± 0.5 | 3.5 ± 0.7 | 2.3 ± 0.5 | 0.001 |
| FVC, L | 4.3 ± 0.9 | 3.4 ± 0.7 | 4.4 ± 0.9 | 3.3 ± 0.8 | 0.05 |
| FEV1/FVC × 100 | 80.7 ± 3.2 | 73.7 ± 9.7 | 79.9 ± 4.8 | 70.5 ± 10.4 | 0.001 |
| FEV1% predicted | 106.2 ± 6.1 | 76 ± 10.4 | 108.5 ± 7.4 | 74.9 ± 12.7 | 0.002 |
| FVC% predicted | 106.1 ± 6.2 | 83.1 ± 11.7 | 109.5 ± 8.9 | 85.3 ± 11.4 | 0.09 |
| Bronchodilator reversibility | 0 (0) | 1 (1.4) | 2 (2.9) | 8 (18.2) | 0.001 |
| TLC, L | 5.7 ± 0.5 | 6 ± 1.4 | 6 ± 1.2 | 6 ± 1.3 | 0.72 |
| DlCO, ml/min/mm Hg | 30.5 ± 2.9 | 23.2 ± 7 | 25.8 ± 6.6 | 23.3 ± 11.7 | 0.54 |
| Baseline COPD | 0 (0) | 19 (27.1) | 2 (2.9) | 18 (40.9) | 0.01 |
| Incident COPD | 2 (5) | 3 (4.3) | 3 (4.4) | 10 (22.7) | 0.01 |
| Days to Inc. COPD | 1,502 ± 775 | 1,101 ± 1021 | 1,506 ± 936 | 525 ± 618 | 0.001 |
| Age at Inc. COPD, yr | 52 ± 7.1 | 49 ± 5 | 49.3 ± 5.5 | 49.5 ± 2.8 | 0.69 |
| FEV% diff. | −4.7 ± 3 | −13.3 ± 15.8 | 8.9 ± 3.2 | 13.4 ± 10.3 | <0.0001 |
| FVC% diff. | −5.5 ± 4.2 | −10.9 ± 10 | 5.8 ± 4.7 | 5.1 ± 9.8 | <0.0001 |
| Ann. absolute FVC diff. | 0.1 | 0.1 | −0.1 | −0.1 | <0.0001 |
| Ann. decline rate, L | 0.06 ± 0.1 | 0.1 ± 0.1 | −0.09 ± 0.1 | −0.1 ± 0.1 | <0.0001 |
| Chron. bronchitis | 10 (25) | 29 (41.4) | 25 (36.8) | 18 (40.9) | 0.29 |
| mMRC score ≥ 2 | 10 (25) | 29 (41.4) | 19 (27.9) | 29 (67.4) | 0.004 |
| SGRQ total | 16.3 ± 17.6 | 24.2 ± 17.3 | 18.2 ± 15.8 | 28.8 ± 20.7 | 0.03 |
| SF-36 total | 118.5 ± 20.5 | 111.4 ± 21.3 | 117.3 ± 17.2 | 104.8 ± 20.5 | 0.04 |
| History of asthma | 7 (17.5) | 19 (27.5) | 15 (22.1) | 8 (18.6) | 0.79 |
Definition of abbreviations: Ann. = annual; BMI = body mass index; Chron. bronchitis = chronic bronchitis (self-reported cough and phlegm for at least 3 mo over the course of 2 consecutive years); COPD = chronic obstructive pulmonary disease; diff. = difference; HS = high school; Inc. = incident; LF = lung function; mMRC = modified Medical Research Council Dyspnea Questionnaire; ND = no decline; RD = rapid decline; SF-36 = 36-Item Short Form Questionnaire; SGRQ = St. George’s Respiratory Questionnaire.
Data are shown as n (%) or mean ± SD. Unless otherwise indicated, all variables shown are at baseline. Significant P values appear in bold. The P values shown are based on the Jonckheere Terpstra test for categorical variables and multivariate analysis of variance for continuous variables.