| Included in this analysis | Study Group | ||
---|---|---|---|---|
 |  | SIA | SIP | UC |
No. of Subjects | N | 457 | 459 | 487 |
 | Y | 1504 | 1503 | 1477 |
Subject Characteristics | ||||
Gender | Â | Â | Â | Â |
% Male | N | 65.6 | 64.3 | 62.6 |
 | Y | 59.3 | 63.9 | 64.2 |
 |  | p =0.0151 | ns | ns |
Age, y | Â | Â | Â | Â |
Mean ± SD | N | 48.7 ± 7.1 | 48.3 ± 6.9 | 48.6 ± 7.0 |
 | Y | 48.3 ± 6.8 | 48.6 ± 6.8 | 48.4 ± 6.8 |
 |  | ns | ns | ns |
Race | Â | Â | Â | Â |
% White | N | 92.8 | 94.8 | 95.3 |
 | Y | 96.9 | 96.1 | 95.7 |
 |  | p =0.0001 | ns | ns |
FEV 1 , L – pre (S2) |  |  |  |  |
Mean ± SD | N | 2.62 ± 0.61 | 2.62 ± 0.58 | 2.59 ± 0.57 |
 | Y | 2.62 ± 0.61 | 2.65 ± 0.60 | 2.66 ± 0.60 |
 |  | ns | ns | p =0.0178 |
FEV 1 , L– post (S2) |  |  |  |  |
Mean ± SD | N | 2.73 ± 0.63 | 2.73 ± 0.60 | 2.70 ± 0.59 |
 | Y | 2.73 ± 0.64 | 2.76 ± 0.63 | 2.78 ± 0.63 |
 |  | ns | ns | p =0.0155 |
BMI, kg/ht 2 | Â | Â | Â | Â |
Mean ± SD | N | 26.0 ± 4.1 | 25.7 ± 3.9 | 25.5 ± 4.1 |
 | Y | 25.3 ± 3.9 | 25.7 ± 3.9 | 25.6 ± 3.9 |
 |  | p =0.002 | ns | ns |
Cigarettes/Day | Â | Â | Â | Â |
Mean ± SD | N | 32.6 ± 13.4 | 32.8 ± 12.8 | 31.8 ± 12.6 |
 | Y | 30.8 ± 13.1 | 31.1 ± 12.5 | 30.9 ± 12.9 |
 |  | p =0.006 | p =0.007 | ns |
Pack/Years | Â | Â | Â | Â |
Mean ± SD | N | 42.6 ± 21.7 | 41.9 ± 19.9 | 41.7 ± 20.6 |
 | Y | 39.8 ± 19.0 | 39.9 ± 18.5 | 40.2 ± 18.3 |
 |  | p =0.027 | ns | ns |
O’Connor slope |  |  |  |  |
Mean ± SD | N | −14.4 ± 28.1 | −12.2 ± 24.1 | −12.6 ± 21.6 |
 | Y | −13.2 ± 23.2 | −12.0 ± 21.3 | −12.9 ± 24.6 |
 |  | ns | ns | ns |