• Electronic Nicotine Delivery Devices
• Non-Cigarette Tobacco Products
• Public Policy

This supplement to Tobacco Control is the product of the State and Community Tobacco Control Research Initiative (SCTC), which consists of seven research projects and a coordinating centre funded through cooperative agreements with the National Institutes of Health, National Cancer Institute (NCI). Research conducted by Initiative members addresses important, understudied aspects of state and community tobacco control policy and media interventions in four areas: secondhand smoke policies; tobacco tax and pricing policies; community and individual behaviour related to tobacco advertising, and mass media actions to counter tobacco advertising; and tobacco industry practices. The Initiative has five interdependent components:

• Multiyear Research Projects, each with several specific aims centred on Initiative-relevant topics.

• Short-term Collaborative Developmental Projects, formed as collaborations among research projects and tobacco control partners to address emerging state and community research needs, and provide opportunities for novel pilot research.

• Working Groups, enabling collaboration among SCTC investigators and relevant partner individuals and organisations to address high-priority gaps in research and practice.

• The NCI, which, in addition to funding the Initiative, contributes to the scientific direction, and evaluates the Initiative process and short-term impact.

• A Coordinating Centre, which serves as an Initiative-wide resource to foster communication and collaboration among components and outside partners, participates in working groups and Initiative evaluation efforts, and facilitates the packaging and dissemination of Initiative research findings.

A full description of the SCTC Initiative is available at (http://sctcresearch.org/PublicHome).

One common objective shared by Initiative components is to conduct research and disseminate findings on topics of high relevance for a wide array of audiences, including: tobacco control programmes; public health practitioners; researchers; and federal, state, and local policy makers. Initiative members engage in strategic partnerships with state and local tobacco control programmes and other voluntary health, advocacy and public health organisations. These partnerships help to assure the relevance of Initiative research, and facilitate rapid adoption of research findings into tobacco control policies and practices.

In 2013, the SCTC steering committee determined that priority audiences share an urgent need for high-quality, relevant research to inform state and community policies and practices related to electronic cigarettes (e-cigarettes) and related electronic nicotine delivery systems (ENDS). Collective SCTC research and dissemination resources and capabilities, guided by close partnerships with the tobacco control community, uniquely positions the Initiative to address questions raised by state and community tobacco control practitioners, advocates and policy makers about ENDS.1 This supplement is a compilation of ENDS research studies conducted by transdisciplinary teams of SCTC investigators and collaborators that collectively address many high-priority research needs relevant to national, state and local tobacco control policies and practices (table 1).

The practice community's immediate need for high-quality scientific data to develop and implement effective policy and programmatic responses to a rapidly evolving ENDS environment was the primary stimulus for this supplement. The papers in this supplement.

• Provide detailed information on ENDS marketing through the internet and social media, and at the point of sale, as well as how tobacco users and non-tobacco users are exposed to, search for, and share ENDS-related information across media platforms,

• Examine the patterns and reasons for e-cigarette use, including information about the impact of electronic cigarette use on vulnerable populations, such as those with mental health conditions.

• Summarise the current state-level ENDS policies.

• Investigate the impact of price and other tobacco control policies on e-cigarette demand.

These papers also contribute to the growing evidence base regarding marketing, use, and impact of ENDS in the USA that supports regulatory actions proposed by the Food and Drug Administration.10

The range of ENDS research topics represented by the papers in this supplement is by no means exhaustive. The topics are necessarily biased towards the areas of focus for the SCTC Research Initiative; for example, high-priority topics, such as issues of harm reduction, product characterisation, health effects and toxicity, are generally not studied within the Initiative despite the research gaps.11 ,12 Moreover, papers published here represent only a portion of the ENDS research being conducted by Initiative investigators, who will continue to publish findings from research on ENDS and other topics relevant to state and community tobacco control.