Yearly progression of low lung attenuation area in low dose CT scan for aymptomatic current smokers with normal lung function or GOLD stage I COPD

TLDR: Measurement of LAA -950 in low-dose CT scan may show individual yearly progression of microscopic emphysema in current smokers with normal lung function or GOLD stage 1 subjects who do not show significant annual changes in lung function.

Abstract: There is still no biomarkers identifying subjects at risk for COPD though the early detection and prevention of COPD is important. The purpose of this study was to investigate if we can identify yearly progression of low lung attenuation area (LAA -950 ) in smokers with normal lung function or GOLD stage 1 COPD. From March 2007 to Oct 2012, initial and annual follow-up low dose CT scans with the measurement of LAA -950 were performed in a total of 86 current smokers (mean age; 48.1 years, mean initial pack years; 27.3±17.98) and 17 non-smokers (mean age; 46.7 years) at our institution. Visceral fat, body fat, BMI, and pulmonary function test (FEV 1 %, FEV 1 /FVC%) were also obtained. Only baseline FEV 1 /FVC% was significantly decreased in smokers compared to non-smokers (mean 77.57±6.59 vs 82.44±4.17, P=0.006) and negatively correlated with smoking pack year (r=-0.355, P=0.001). However, only LAA -950 was significantly increased (mean 7.88±3.93, vs 9.85±5.50, p=0.001) in smokers after one year. BMI (23.88±2.54 vs 23.88±2.56), visceral fat (100.41± 16.81 vs 100.73±19.74), body fat (21.29±3.96 vs 21.64±3.88), FEV 1 % (99.80±12.63 vs 99.33±12.67) and FEV 1 /FVC% (77.57±6.59 vs 77.39±6.47) were not changed (P>0.05) in smokers on the annual follow-up study. There were no significant differences in the paired LAA -950 , BMI, visceral fat, body fat, FEV 1 % and FEV 1 /FVC% in non-smokers on the annual follow-up study. Measurement of LAA -950 in low-dose CT scan may show individual yearly progression of microscopic emphysema in current smokers with normal lung function or GOLD stage 1 subjects who do not show significant annual changes in lung function.