Short-term effect of changes in smoking behaviour on emphysema quantification by CT

TY - JOUR

T1 - Short-term effect of changes in smoking behaviour on emphysema quantification by CT

AU - Ashraf, Haseem

AU - Lo, Pechin Chien Pau

AU - Shaker, Saher Burhan

AU - de Bruijne, Marleen

AU - Dirksen, Asger

AU - Tønnesen, Philip

AU - Dahlbäck, Magnus

AU - Pedersen, Jesper Johannes Holst

PY - 2011/1

Y1 - 2011/1

N2 - Background: The effect of smoking cessation and smoking relapse on lung density was studied using low-dose CT. Methods: Spiral, multidetector, low-dose CT was performed on 726 current and former smokers (>20 pack-years) recruited from a cancer screening trial. Lung density was quantified by calculating the 15th percentile density (PD15), which was adjusted to predicted total lung capacity. Data were analysed by linear regression models. Results: At baseline mean PD15 was 45 g/l in former smokers (n=178) and 55 g/l in current smokers (n=548), representing a difference of 10 g/l (p<0.001). After smoking cessation (n=77) PD15 decreased by 6.2 g/l (p<0.001) in the first year, and by a further 3.6 g/l (p<0.001) in the second year, after which no further change could be detected. Moreover, the first year after relapse to smoking (n=18) PD15 increased by 3.7 g/l (p=0.02). Conclusions: Current smoking status has a major influence on lung density assessed by CT, and the difference in lung density between current and former smokers observed in cross-sectional studies corresponds closely to the change in lung density seen in the years after smoking cessation. Current smoking status, and time since cessation or relapse, should be taken into account when assessing the severity of diseases such as emphysema by CT lung density.

AB - Background: The effect of smoking cessation and smoking relapse on lung density was studied using low-dose CT. Methods: Spiral, multidetector, low-dose CT was performed on 726 current and former smokers (>20 pack-years) recruited from a cancer screening trial. Lung density was quantified by calculating the 15th percentile density (PD15), which was adjusted to predicted total lung capacity. Data were analysed by linear regression models. Results: At baseline mean PD15 was 45 g/l in former smokers (n=178) and 55 g/l in current smokers (n=548), representing a difference of 10 g/l (p<0.001). After smoking cessation (n=77) PD15 decreased by 6.2 g/l (p<0.001) in the first year, and by a further 3.6 g/l (p<0.001) in the second year, after which no further change could be detected. Moreover, the first year after relapse to smoking (n=18) PD15 increased by 3.7 g/l (p=0.02). Conclusions: Current smoking status has a major influence on lung density assessed by CT, and the difference in lung density between current and former smokers observed in cross-sectional studies corresponds closely to the change in lung density seen in the years after smoking cessation. Current smoking status, and time since cessation or relapse, should be taken into account when assessing the severity of diseases such as emphysema by CT lung density.

U2 - 10.1136/thx.2009.132688

DO - 10.1136/thx.2009.132688

M3 - Journal article

C2 - 20978026

SN - 0040-6376

VL - 66

SP - 55

EP - 60

JO - Thorax

JF - Thorax

IS - 1

ER -