Tobacco and Nicotine Use Among US Adult "Never Smokers" in Wave 4 (2016-2018) of the Population Assessment of Tobacco and Health Study.

The <100 lifetime cigarettes criterion may not capture what many would consider true "never smokers." Relying on the current definition of "never smokers" as a reference group will include a substantial number of those currently and recently using combustible tobacco and thus produce data that may underestimate the relative harm from cigarettes. Prospective longitudinal research is needed to compare how the 100-cigarette lifetime threshold versus other definitions of regular cigarette smoking differ in predictive validity of clinically meaningful outcomes and health harms to determine the optimal criteria to define established cigarette smoking.