Over the past several decades, adenocarcinoma of the lung has been increasing as a fraction of all lung cancer. Examination of the available evidence led the 2014 Report of the Surgeon General to conclude that the increases in the rates of adenocarcinoma among smokers in the U.S. were a result of changes in cigarette design and composition over the past 6 decades. While a causal link to design and composition changes as a whole is clear, the changes that have been implemented over the past several decades are not uniformly applied across all cigarette brands in the current market, raising questions about differences in risks among users of different cigarette brands. Recognition of the increased risks resulting from design and composition changes offers a corollary opportunity to reduce current disease risks by identifying and regulating the specific compositional and design changes that produced the increase in risk.