Low-angle overthrust faulting, as illustrated by the Cumberland Plateau-Sequatchie Valley fault system

Abstract

<h3>Background</h3> We present the final results of the effect of lung cancer screening with low-dose CT on the smoking habits of participants in a 5-year screening trial. <h3>Methods</h3> The Danish Lung Cancer Screening Trial (DLCST) was a 5-year screening trial that enrolled 4104 subjects; 2052 were randomised to annual low-dose CT (CT group) and 2052 received no intervention (control group). Participants were current and ex-smokers (≥4 weeks abstinence from smoking) with a tobacco consumption of ≥20 pack years. Smoking habits were determined annually. Missing values for smoking status at the final screening round were handled using two different models. <h3>Results</h3> There were no statistically significant differences in annual smoking status between the CT group and control group. Overall the ex-smoker rates (CT + control group) significantly increased from 24% (baseline) to 37% at year 5 of screening (p&lt;0.001). The annual point prevalence quit rate increased from 11% to 24% during the five screening rounds; the ex-smokers’ relapse rate remained stable, around 11%, across the same period. <h3>Conclusions</h3> Screening with low-dose CT had no extra effect on smoking status compared with the control group, but overall the screening programme probably promoted smoking cessation. <h3>Clinical Trial Registration:</h3> The DLCST is registered in Clinical Trials.gov Protocol Registration System (identification no. NCT00496977).