摘要：In recent years, a renewed debate has developed around the potential for modified tobacco products to play a role in reducing tobacco-related harm. During the 1960s and 1970s medical experts recommended to smokers who could not quit that they switch to cigarettes with lower tar and nicotine content. At the time, survey data suggested that smokers who switched did not compensate for the reduction in nicotine by increasing their intake. However, public health scientists were hindered in their ability to evaluate the population impact of the reduced tar strategy by a limited understanding of nicotine addiction. Smoking dependence was seen as primarily psychological and social, rather than pharmacological or biological, until the late 1970s, when addiction researchers began to apply experimental techniques from other forms of drug abuse to study smoking behavior. This history has important lessons for current discussions about tobacco harm reduction and regulation of nicotine delivery. OVER THE PAST 10 YEARS, the concept of tobacco harm reduction—reducing the morbidity and mortality from tobacco use without necessarily eliminating exposure to tobacco or nicotine—has drawn increasing attention and discussion among tobacco control scientists and public health professionals. 1 Proponents of harm reduction argue that cigarette smokers who are unable or unwilling to quit may benefit from harm-reduction strategies, similar to approaches used for other forms of drug abuse. 2 Additionally, the Family Smoking Prevention and Tobacco Control Act of 2009 (P.L. 111–131) granted the US Food and Drug Administration authority to regulate tobacco products, including establishing product standards for harmful constituents and nicotine content, with the aim of protecting public health. Internationally, there have been efforts to develop principles and guidelines for the regulation of tobacco products with the aim of reducing toxic exposures. 3 However, the concept of tobacco harm reduction has also generated substantial controversy. 4 Skeptics warn that harm reduction interventions may have unintended adverse consequences, as perceptions that a product is less harmful or “safe” may lead to increased initiation and relapse or a decrease in cessation attempts. 5 Additionally, past efforts at tobacco harm reduction may have done more harm than good. During the 1960s and 1970s scientists and public health officials encouraged cigarette smokers to switch to cigarette brands with lower tar and nicotine content. 6 Decades later, “light” and “ultralight” brands still make up nearly 85% of the cigarettes sold in the United States. 7 But extensive epidemiological data have failed to show any benefit from changes in cigarette design over the past half century. 8 So why did this failed harm-reduction strategy persist over more than two decades and how was it finally overturned? Previous research and investigations based on internal tobacco industry documents have shown how, beginning in the 1960s, cigarette manufacturers manipulated nicotine delivery in their products in ways that would not be detected by machine measurements and that they secretly conducted research demonstrating that smokers modified their nicotine intake when smoking low-tar cigarettes. 9 However, in this article I argue that public health scientists, who were not privy to internal tobacco industry research, were hindered in their ability to evaluate the impact of low-tar cigarettes by a lack of understanding of nicotine addiction and its impact on smoking behavior. Although early reports on the health effects of cigarette smoking during the 1960s described the smoking “habit” and identified a range of psychological and social factors responsible for driving smoking behavior, there was little attention to or understanding of the biological basis of such behaviors. Indeed, the view that smoking dependence was primarily psychological and social prevailed well into the 1980s. 10 This history has important lessons for current tobacco harm-reduction efforts, which continue to focus primarily on product toxicity without sufficiently addressing changes to the addictiveness of the product or smoking behavior.
