This report considers the biological and behavioral mechanisms that may underlie the pathogenicity of tobacco smoke. Many Surgeon General's reports have considered research findings on mechanisms in assessing the biological plausibility of associations observed in epidemiologic studies. Mechanisms of disease are important because they may provide plausibility, which is one of the guideline criteria for assessing evidence on causation. This report specifically reviews the evidence on the potential mechanisms by which smoking causes diseases and considers whether a mechanism is likely to be operative in the production of human disease by tobacco smoke. This evidence is relevant to understanding how smoking causes disease, to identifying those who may be particularly susceptible, and to assessing the potential risks of tobacco products.

This booklet for schools, medical personnel, and parents contains highlights from the 2012 Surgeon General's report on tobacco use among youth and teens (ages 12 through 17) and young adults (ages 18 through 25). The report details the causes and the consequences of tobacco use among youth and young adults by focusing on the social, environmental, advertising, and marketing influences that encourage youth and young adults to initiate and sustain tobacco use. This is the first time tobacco data on young adults as a discrete population have been explored in detail. The report also highlights successful strategies to prevent young people from using tobacco.

Tobacco use by adolescents and young adults poses serious concerns. Nearly all adults who have ever smoked daily first tried a cigarette before 26 years of age. Current cigarette use among adults is highest among persons aged 21 to 25 years. The parts of the brain most responsible for cognitive and psychosocial maturity continue to develop and change through young adulthood, and adolescent brains are uniquely vulnerable to the effects of nicotine. At the request of the U.S. Food and Drug Administration, Public Health Implications of Raising the Minimum Age of Legal Access to Tobacco Products considers the likely public health impact of raising the minimum age for purchasing tobacco products. The report reviews the existing literature on tobacco use patterns, developmental biology and psychology, health effects of tobacco use, and the current landscape regarding youth access laws, including minimum age laws and their enforcement. Based on this literature, the report makes conclusions about the likely effect of raising the minimum age to 19, 21, and 25 years on tobacco use initiation. The report also quantifies the accompanying public health outcomes based on findings from two tobacco use simulation models. According to the report, raising the minimum age of legal access to tobacco products, particularly to ages 21 and 25, will lead to substantial reductions in tobacco use, improve the health of Americans across the lifespan, and save lives. Public Health Implications of Raising the Minimum Age of Legal Access to Tobacco Products will be a valuable reference for federal policy makers and state and local health departments and legislators.

Millions of Americans use e-cigarettes. Despite their popularity, little is known about their health effects. Some suggest that e-cigarettes likely confer lower risk compared to combustible tobacco cigarettes, because they do not expose users to toxicants produced through combustion. Proponents of e-cigarette use also tout the potential benefits of e-cigarettes as devices that could help combustible tobacco cigarette smokers to quit and thereby reduce tobacco-related health risks. Others are concerned about the exposure to potentially toxic substances contained in e-cigarette emissions, especially in individuals who have never used tobacco products such as youth and young adults. Given their relatively recent introduction, there has been little time for a scientific body of evidence to develop on the health effects of e-cigarettes. Public Health Consequences of E-Cigarettes reviews and critically assesses the state of the emerging evidence about e-cigarettes and health. This report makes recommendations for the improvement of this research and highlights gaps that are a priority for future research.