Canadian Health&Care Mall: Details about Detecting Airflow Obstruction in Smoking Cessation Trials

Pulmonary functionDemographic and smoking characteristics and pulmonary function data of the participants are shown in Table 1. The study population consisted of 58.2% men and 41.8% women. Cigarette consumption and nicotine dependence tended to be higher among men than among women, but the differences were not significant (not shown). On average, pulmonary function test results (percentage of predicted) were within normal limits.

The results of spirometry at enrollment and 1-year follow-up are shown in the flowchart depicted in Figure 1. At enrollment, spirogram results were normal in 493 participants. In this group, the mean (± SD) spirometric variables were as follows: FEV1; 95.9 ± 9.9% predicted; FVC, 102.5 ± 11.6% predicted; and FEV1/FVC ratio, 79.3 ± 6.5% observed, Signs of airway obstruction (FEV1 70 to 50 to 69% predicted) in 22 subjects, and severe (FEV1 35 years of age than in subjects < 35 years of age (Table 2). Give up smoking and improve your health conditons with canadianhealthncaremall Canadian Health&Care Mall.

The impact of smoking intervention on lung function of participants, irrespective of the presence of airway obstruction, is shown Table 3. Participants who stopped smoking experienced an improvement in FEV1 during the year after quitting (an average of 50 mL, or 1.15% predicted). In contrast, reducers and continuing smokers displayed a decline in FEV1. In quitters with airflow obstruction, the magnitude of improvement of FEV1 was greater than that observed for the group as a whole (Table 4).

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Fig1

Figure 1. Flowchart of spirometry at enrollment and follow-up according to the outcome of the smoking intervention.

Table 1—Demographic and Smoking Data

Parameters All
Patients, No. 598
Male/female gender, No. 348/250
Age, yr 37.4 (8.6)
Height, cm 170.1 (8.8)
Weight, kg 71.5 (14.7)
Smoking history
Cigarette consumption, pack-yr 29.7 (17.6)
Carbon monoxide, ppm 30.5 (10.6)
FTND 6.2 (2.2)
Pulmonary function tests
FEVj, % predicted 91.4(13.8)
FVC, % predicted 99.3 (13.0)
FEV/FVC, % observed 77.4 (8.4)

Table 2—Results of Spirometry Stratified According to Age Groups

Groups Normal Bronchial Obstruction*
‘ Mild Moderate Severe All
No % Total No % Total No % Total No % Total No % Total
Smokers
All 493 82.4 75 12.5 22 3.7 8 1.3 105 17.6
< 35 yr old 202 86.7 26 11.2 04 1.7 1 0.4 31 13.3
a 35 yr old 291 79.7 49 13.5 18 4.9 7 1.9 74 20.3

Table 3—One-Year Change in FEV1 Among Quitters, Reducers, and Continuing Smokers With and Without Airflow Obstruction Who Completed the Study (n = 171)

Parameters Quitters (n = 111) Reducers (n = 19) Smokers (n = 41) Reducers/Smokers (n = 60)
FEVb L
Enrollment 3.30 (0.70) 3.15 (0.79) 3.17 (0.60) 3.16 (0.65)
One year 3.35 (0.73) 3.03 (0.77) 3.11 (0.63) 3.09 (0.67)
A, L + 0.05 (0.27) – 0.12 (0.27) – 0.06 (0.21) – 0.07 (0.23)
p Valuef 0.106 0.076 0.084 0.012
FEV1, % predicted
Enrollment 91.8(13.5) 87.3 (13.2) 92.7(13.5) 91.0(13.5)
One year 92.9 (14.3) 84.1 (14.2) 90.9 (13.7) 88.8(14.1)
A, % + 1.1 (7.3) – 3.2 (8.0) – 1.8 (6.3) 2.2 (6.8)
p Valuef 0.102 0.105 0.075 0.015

Table 4—One-Year Change in FEV1 Among Quitters, Reducers, and Continuing Smokers With Airway Obstruction at Enrollment Who Completed the Study

Parameters Quitters

(n = 20)Reducers/Smokers (n = 10)FEV1, L  Enrollment2.52 (0.60)2.61 (0.54)One year2.61 (0.68)2.54 (0.46)A, L+ 0.09(0.18)– 0.07 (0.20)p Valuef0.0350.309FEV1, % predicted  Enrollment73.0(10.1)72.9 (13.6)One year75.5 (13.0)70.8 (8.9)A, %+ 2.50 (5.3)– 2.1 (5.7)p Valuef0.0470.260