Table 1. The Baseline Characteristics of the Lung Health Study Participants According to Quintiles of Myeloperoxidase Levels in Serum at Year 5.
| Quint1 | Quint2 | Quint3 | Quint4 | Quint5 | P | |
| Number | 935 | 936 | 935 | 936 | 935 | |
| Myeloperoxidase (ng/ml) | 36.0±9.9 | 65.7±8.3 | 97.9±10.9 | 147.5±19.0 | 290.9±151.7 | <.0001 |
| Age (years) | 54.2±6.7 | 53.3±6.9* | 53.6±6.7 | 53.3±6.7* | 52.7±6.9* † | 0.0001 |
| Men (%) | 61.9% | 62.0% | 63.6% | 62.8% | 65.6% | 0.4567 |
| White (%) | 97.0% | 96.0% | 95.0% | 97.0% | 97.0% | 0.0660 |
| BMI (kg/m2) | 25.7±3.7 | 25.7±4.1 | 25.5±3.8 | 25.4±3.8 | 25.6±4.1 | 0.4357 |
| Age at which smoking began (years) | 17.7±4.3 | 17.6±3.9 | 17.5±3.8 | 17.4±3.6 | 17.3±3.5 | 0.0708 |
| Smoking duration (pack-years) | 39.8±18.8 | 39.6±18.8 | 40.1±18.4 | 40.2±18.6 | 40.8±18.5 | 0.5725 |
| Sustained quitters (%) | 22.6% | 22.3% | 19.7% | 13.6% | 10.1% | <.0001 |
| Intermittent quitters (%) | 32.2% | 30.8% | 25.9% | 26.8% | 25.7% | |
| Continuing smokers (%) | 45.2% | 46.9% | 54.4% | 59.6% | 64.3% | |
| FEV1% Predicted at recruitment (year 0) | 78.4±9.2 | 78.5±9.1 | 78.6±8.9 | 78.0±9.0 | 78.7±9.0 | 0.4372 |
| FEV1% at blood draw (year 5) | 76.1±12.1 | 75.6±12.2 | 75.1±11.7 | 73.8±12.3 | 74.6±12.0* | 0.0005 |
| FEV1% at year 11 | 70.7±14.5 | 70.1±15.3 | 68.8±14.6 | 68.3±15.4* | 68.3±15.6* | 0.0049 |
| CRP (mg/L) | 1.11 (1.66)‡ | 1.21 (2.01)‡ | 1.39 (2.39)‡ | 1.56 (2.78)‡ | 1.90 (3.50)‡ | <.0001 |
Abbreviations: FEV1, forced expiratory volume in 1 second; BMI, body mass index. Study participants were divided into 5 identical groups based on myeloperoxidase levels. Data are presented as mean ± SD.
*
p<.05 versus quintile 1.
†
p<.05 versus quintile 2.
‡
p<.05 versus each other.