Strengths of this study include the examination of lung cancer mortality in a large cohort of 188,699 lifelong never-smokers to eliminate potential residual confounding by cigarette smoking status; an extended 26-year follow-up time period (1982–2008) with a total of 1,100 observed lung cancer deaths; detailed prospectively collected individual-level lung cancer risk factor data; and the availability of ecologic measures of residential radon concentrations and sociodemographic characteristics to examine potential confounding by radon and community-level factors.