Characteristics of participants in the Lung Health Study according to quintiles of baseline CRP levels
| Quintile 1(n = 960) | Quintile 2(n = 961) | Quintile 3(n = 961) | Quintile 4(n = 961) | Quintile 5(n = 960) | p for trend* | |
|---|---|---|---|---|---|---|
| CRP, C-reactive protein; BMI, body mass index; FEV1, forced expiratory volume in 1 second; BP, blood pressure. | ||||||
| *Linear trend from quintile 1 to quintile 5. | ||||||
| †Geometric mean (interquartile range). | ||||||
| ‡Post-bronchodilator values. | ||||||
| Continuous variables are presented as mean (SD) and dichotomous variables are presented as number of participants (% column totals) unless otherwise indicated. | ||||||
| CRP (mg/l)† | 0.21 (0.17–0.39) | 0.73 (0.62–0.86) | 1.39 (1.21–1.61) | 2.58 (2.17–3.06) | 7.06 (4.79–9.02) | <0.001 |
| Age (years) | 52 (7) | 53 (7) | 54 (7) | 54 (7) | 55 (6) | <0.001 |
| Men | 568 (59%) | 617 (64%) | 660 (69%) | 630 (66%) | 548 (57%) | 0.568 |
| Whites | 932 (97%) | 936 (97%) | 933 (97%) | 925 (96%) | 897 (93%) | <0.001 |
| Pack-years of smoking | 37 (18) | 39 (18) | 41 (18) | 42 (20) | 42 (19) | <0.001 |
| Continued smokers | 470 (49%) | 509 (53%) | 509 (53%) | 536 (56%) | 577 (60%) | <0.001 |
| Intermittent smokers | 296 (31%) | 275 (28%) | 269 (28%) | 267 (28%) | 244 (25%) | 0.011 |
| Daily cough | 317 (33%) | 341 (35%) | 344 (36%) | 333 (35%) | 352 (37%) | 0.185 |
| Daily sputum | 273 (28%) | 287 (30%) | 306 (32%) | 287 (30%) | 313 (33%) | 0.076 |
| BMI (kg/m2) | 24.1 (3.6) | 25.2 (3.6) | 25.6 (3.5) | 26.3 (4.0) | 26.6 (4.2) | <0.001 |
| FEV1 (l)‡ | 2.80 (0.63) | 2.80 (0.64) | 2.80 (0.63) | 2.74 (0.63) | 2.61 (0.59) | <0.001 |
| FEV1 (% predicted)‡ | 80 (9) | 79 (9) | 78 (9) | 78 (10) | 77 (9) | <0.001 |
| Diastolic BP | 76 (9) | 78 (9) | 79 (9) | 79 (9) | 79 (9) | <0.001 |
| Systolic BP | 119 (14) | 121 (15) | 123 (15) | 123 (14) | 125 (16) | <0.001 |