Table 1

 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
Men568 (59%)617 (64%)660 (69%)630 (66%)548 (57%)0.568
Whites932 (97%)936 (97%)933 (97%)925 (96%)897 (93%)<0.001
Pack-years of smoking37 (18)39 (18)41 (18)42 (20)42 (19)<0.001
Continued smokers470 (49%)509 (53%)509 (53%)536 (56%)577 (60%)<0.001
Intermittent smokers296 (31%)275 (28%)269 (28%)267 (28%)244 (25%)0.011
Daily cough317 (33%)341 (35%)344 (36%)333 (35%)352 (37%)0.185
Daily sputum273 (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 BP76 (9)78 (9)79 (9)79 (9)79 (9)<0.001
Systolic BP119 (14)121 (15)123 (15)123 (14)125 (16)<0.001