MedicalResearch.com: What is the background for this study?
Response: Since first entering the U.S. marketplace in 2007, e-cigarettes have been a rapidly evolving product class. Typically, national surveys provide annual, self-reported estimates of e-cigarette use among adults and youth. However, given the dynamic nature of the e-cigarettes landscape, data collected at a sub-annual level can be useful for identifying rapid changes and patterns. For example, retail sales data, which is available at more frequent intervals, such as weekly, can complement annual surveys and help keep a pulse on emerging trends. This study assessed e-cigarette retail sales data in the United States from 2013 through 2017.