PhenX: Host: Biobehavioral measures for tobacco regulatory research.

A working group (WG) of experts from diverse fields related to nicotine and tobacco addiction was constituted to identify constructs and measures for the PhenX (Phenotypes and eXposures) Tobacco Regulatory Research (TRR) Host: Biobehavioral Collection with potential relevance to users of both conventional and newer tobacco products. This paper describes the methods and results the WG used to identify, select, approve and place measures in the PhenX TRR Collection. The WG recognised 13 constructs of importance to guide their categorisation of measures already in the PhenX Toolkit ('complementary measures') and to identify novel or improved measures of special relevance to tobacco regulatory science. In addition to the 22 complementary measures of relevance to tobacco use already in the PhenX Toolkit, the WG identified and recommended nine additional Host: Biobehavioral measures characterising the use, exposure and health outcomes of tobacco products for application to TRR. Of these, five were self-administered or interviewer-administered measures: amount, type and frequency of recent tobacco use; flavor preference in e-cigarette users (adult and youth); pregnancy status and tobacco use; pregnancy status-mother and baby health and withdrawal from tobacco use. The remaining four measures were laboratory-based: cotinine in serum, expired carbon monoxide, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in urine and cue reactivity. Although a number of validated tools are now available in the Host: Biobehavioral Collection, several gaps were identified, including a need to develop and test the identified measures in adolescent samples and to develop or identify measures of nicotine dependence, tolerance and withdrawal associated with newer non-combusted tobacco products.