| All participants(N = 1488) | Rate of decline study | Baseline lung function study | |||||
| Fast decliners(n = 266) | Non-decliners(n = 293) | p Value | High function(n = 532) | Low function(n = 527) | p Value | ||
| Gender (M/F) | 948/540 | 158/108 | 197/96 | N/A | 352/180 | 325/202 | N/A |
| Age (years) | 48.41 (0.18) | 49.47 (0.40) | 47.48 (0.40) | <0.001 | 46.21 (0.77) | 50.76 (0.26) | <0.001 |
| Smoking history (pack-years)* | 40.41 (0.48) | 43.23 (1.18) | 38.35 (1.06) | 0.002 | 35.33 (0.13) | 45.24 (0.81) | <0.001 |
| Smoking status during 5-year follow-up† | |||||||
| Continuing smokers | 979 | 266 | 293 | N/A | 264 | 286 | N/A |
| Intermittent quitters | 315 | N/A | N/A | N/A | 157 | 158 | N/A |
| Sustained quitters | 194 | N/A | N/A | N/A | 111 | 83 | N/A |
| BMI (kg/m2) | 25.49 (0.10) | 25.22 (0.25) | 25.77 (0.21) | 0.091 | 25.39 (0.15) | 25.57 (0.18) | 0.455 |
| ΔFEV1/year (% predicted pre-BD)‡ | −0.98 (0.05) | −4.13 (0.07) | 1.09 (0.04) | <0.001 | −0.55 (0.07) | −1.22 (0.08) | <0.001 |
| ΔFEV1/year (% predicted post-BD)§ | −0.85 (0.04) | −3.44 (0.08) | 0.70 (0.05) | <0.001 | −0.75 (0.06) | −0.74 (0.08) | 0.949 |
| Baseline FEV1 (% predicted pre-BD)¶ | 74.15 (0.30) | 72.68 (0.54) | 75.51 (0.47) | <0.001 | 86.49 (0.13) | 61.07 (0.18) | <0.001 |
| Baseline FEV1 (% predicted post-BD)** | 77.57 (0.34) | 75.00 (0.56) | 79.80 (0.47) | <0.001 | 91.81 (0.10) | 62.57 (0.14) | <0.001 |
| Median (IQR) IL6 (pg/ml) | 2.60 (1.80–4.20) | 2.75 (2.00–4.03) | 2.70 (1.70–4.50) | 0.184 | 2.50 (1.70–3.90) | 2.70 (1.85–4.55) | 0.12 |
Values are mean (SEM) for continuous data.
BD, bronchodilator; BMI, body mass index; FEV1, forced expiratory volume in 1 s; IL6, interleukin 6.
*Number of packs of cigarettes smoked per day × number of years smoking.
†Continuing smokers: participants who reported smoking at each annual visit. Sustained quitters: participants who were validated by salivary cotinine or exhaled carbon monoxide levels as abstinent at every annual visit. Intermittent quitters: participants who were not sustained quitters or continuing smokers.
‡Change in lung function over a 5-year period per year as pre-bronchodilator percentage predicted FEV1.
§Change in lung function over a 5-year period per year as post-bronchodilator percentage predicted FEV1.
¶Lung function at the start of the Lung Health Study as measured by pre-bronchodilator FEV1 percentage predicted.
**Lung function at the start of the Lung Health Study as measured by post-bronchodilator FEV1 percentage predicted.