For many western nations, the First World War established smoking as a majority behavior among men while women took it up in the late 1920s. The cigarette, as far as we know, did not change much until after the Second World War. The advent of Idelalisib CLL the filter after that war rapidly took over the market, perhaps encouraged by the increasing evidence of the harmfulness of smoking and the hope that filters would reduce the harms. Filters were then promoted as a harm-reduction strategy, even though this has proved to be illusory (U.S. Department of Health and Human Services [USDHHS], 2001). Changes to the tobacco market in the developing world were slower, and in some cases, relatively simple cigarettes are still available at the bottom end of the market in many countries.

Indeed, cottage industry production is still an important in countries like India, especially for the cigarette-like bidi. In the 1960s and 1970s, public health advocates and some health authorities focused their attention on the possibility of reducing the harmfulness of cigarettes. This effort was based on logic that seemed sound at the time. Wynder and Graham (1950) and Doll and Hill (1950) demonstrated a dose response between cigarette consumption and disease. Wynder, Graham, and Croninger (1953) demonstrated a dose response between tobacco tar applied to mouse skin and the tumor response so it was logical to think that a reduction in the number of tar particles applied to the lung would reduce disease potential.

Although this view was relatively simple and restricted to the numeric, nobody believed that the tobacco industry would reduce measured tar in ways that were unrelated to actual human exposures and may have increased the risk of disease. The main means of achieving this improbable outcome was through the use of filter venting (King, Carter, Borland, Chapman, & Gray, 2003; Kozlowski, Frecker, Khouw, & Pope, 1980). The main effect of this is that it resulted in smokers changing the way they puff on cigarettes to ensure they received their target dose of nicotine. The differences in burn rates and the changes in puffing changed both the mix of carcinogens and toxins and the way they are deposited in the lungs. For example, filter vented American blend cigarettes produce higher levels of tobacco-specific nitrosamines (Gray et al., 2000; Hoffmann, Djordjevic, & Hoffmann, 1997). This and the deeper puffing have been linked to an increase in the incidence of adenocarcinoma that has occurred since their introduction (Burns, Anderson, Anacetrapib & Gray, 2011a, 2011b). From the 1960s, at least there have been a great many changes made to the cigarettes sold in many parts of the world (Hoffmann & Hoffmann, 1994; Hoffmann, Hoffmann, & El-Bayoumy, 2001).