Association of Cigarette Type With Lung Cancer Incidence and Mortality

Abstract

In response to increasing evidence implicating cigarette smoking as a cause of lung cancer in the 1950s, tobacco manufacturers introduced filtered and "lower-tar" cigarettes to allay consumer concerns, knowing they did not actually reduce health risks. Puncturing ventilation holes of varying sizes and numbers into the filter to dilute inhaled smoke became the optimum way to reduce tar yield. 1 Despite these changes, smoking remains responsible for 80% to 90% of lung cancer diagnoses and 5-year survival is 18%, highlighting the importance of prevention. 2 Lung cancer screening with low-dose computed tomography has been shown to improve mortality, and tobacco treatment is a required component of effective screening. We investigated the association of filter status, tar level, and menthol flavor with lung cancer outcomes in the National Lung Screening Trial. Methods | This is a secondary data analysis of 14 123 National Lung Screening Trial participants who completed detailed smoking questionnaires. 3 We examined baseline cigarette tar level (regular, light, or ultralight), flavor (unflavored or menthol), and filter status (filtered or unfiltered) and their association with lung cancer diagnosis, mortality, and all-cause mortality. Cox regression models were used to study the influence of cigarette tar level, flavor, and filter on clinical outcomes, controlling for sex, age, race, pack years, nicotine dependence (as measured by the Fagerström Test for Nicotine Dependence), and treatment arm. This study was approved by the Medical University of South Carolina institutional review board. Patient consent was waived because deidentified data were used. Two-sided t testing was conducted as indicated with a P value less than .05 being considered significant. Results | Of 14 123 participants, 7056 (50%) were current smokers , 13 038 (92%) were white, and had a history of smoking an average of 60 pack of cigarettes per year (Table 1). Most individuals (12 488 [88%]) smoked filtered cigarettes, and nearly half smoked light (4660 [33.0%]) or ultralight (1562 [11.1%]) cigarettes. After adjustment, unfiltered cigarette smokers were nearly 40% (hazard ratio, 1.37; 95% CI, 1.10-1.17) more likely to develop lung cancer and nearly twice (hazard ratio, 1.96; 95% CI, 1.46-2.64) as likely to die of lung cancer compared with those who smoked filtered cigarettes. Additionally, all-cause mortality was nearly 30% (hazard ratio, 1.28; 95% CI, 1.09-1.50) higher (Table 2). There was no difference in mortality outcomes between light/ultralight or flavored vs regular cigarette smokers.