| Research Abstract |
To determine the incidence of pulmonary emphysema (PE) and its severity identified by computed tomography (CT) screening for lung cancer.
We reviewed 2,731 cases (1,890 men and 841 women, ranging in age from 21-91 years) who underwent CT scanning. CT findings were judged abnormal if there were areas of low attenuation. Among the men, there were 1592 smokers including ex-smokers and 298 non-smokers. On the other hand, there were 114 female smokers including ex-smokers, and 727 non-smokers. CT findings were classified into normal and four grades (1-4) ; grade 1, mild, to grade 4, severe. In all cases, contiguous 1-cm sections encompassed the entire thorax without using high-resolution reconstruction.
PE was found in 827 of 1.592 (51.9%) male smokers and in 6 of 298 (2.0%) non-smokers. Among women, PE was found in 27 of 114 (23.7%) smokers and in 10 of 727 (1.4%) non-smokers. Among male smokers, the prevalence of PE by grade was : grade 1, n=383 ; grade 2, n=206 ; grade 3, n=154 and grade 4, n=84. Among female smokers, the prevalence of PE by grade was : grade 1, n=17 ; grade 2, n=6 ; grade 3, n=4 and grade 4, n=0. The incidence of PE in men in each age group : less than 30 years, n=8 (of 27, 29.6%) ; 30's, n=33 (of 90, 36.7%), 40's, n=138 (of 294, 46.9%) ; 50's, n=241 (of 507, 47.6%) ; 60's, 231 (of 406, 56.9%) ; and 70's, n=176 (of 268, 65.7%).
PE can be found in young subjects even in those under age 30 years. Although PE can occur in nonsmokers, PE is strongly related to smoking and progresses with age and cumulative cigarette smoking dose. PE was found in more than half of male smokers on average.
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