Tanner NT, et al. – In response to mounting evidence highlighting cigarette smoking as a cause of lung cancer in the 1950s, tobacco manufacturers founded filtered and “lower-tar” cigarettes to mollify consumer attention, knowing they did not really decrease health risks. Perforating airing slots of differing sizes and numbers into the filter to dilute breathed smoke became the best way to decrease tar production. Researchers thus performed a secondary analysis of the National Lung Screening trial to determine the association of cigarette type with lung cancer incidence and death.